Life Sciences en Don't Teach Your Kids to Attack the Planet <span>Don&#039;t Teach Your Kids to Attack the Planet</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><p>Life has been growing on Earth for about 4 billion years, and during that time there have been a handful of mass extinctions that have wiped out a large percentage of complex lifeforms.  Asteroid impact, volcanic eruption, climate change, anoxia, and poison have dispatched untold numbers of once-successful species to total oblivion or a few lucky fossils.  Species also die off regularly for much less spectacular reasons, and altogether <a title="Wikipedia" href="" target="_blank" rel="noopener noreferrer">about 98% of documented species</a> no longer exist.</p> <p>Cry me a river, you say, without all that death there would have been no gap for vertebrates, for mammals, for primates, for humanity to emerge.  The tyrannosaurus-less world we awoke to find ourselves on had regained an incredible array of plant, animal, fungal, and microbial diversity, exploiting and even celebrating every ecological niche on the planet.  Our ancestors, a small population of soft, slow-moving meatbags, lifted their hands from the ground and set about smashing, shaping, shooting, burning, cutting and consuming their way to the top.  Although human tribes spread to inhabit every continent except Antarctica, the limits of the world remained unknown, no less to tribal cultures than to pre-Columbian Europe.  There was always the promise of more land, more meat, and more resources for the taking—perhaps not within easy reach, but somewhere near the horizon.</p> <p>Even after Europe discovered the "new" world, attitudes of conquest and dominion were rarely given second thought.  Manifest destiny drove United States citizens from sea to shining sea, eradicating all kinds of biodiversity along the way.  We not only disregarded the finity of plants and animals, but of a remarkably diverse race of peoples who lived in equilibrium with a world they recognized as precious. But after the West was won, the global balance of power shifted very quickly.  Industry, technology, and medicine led to unprecedented health and fecundity.  Global population exploded exponentially.  There was nowhere left to go.</p> <p>Now it is humanity that strives toward limitlessness while the world seems to dwindle, inexorably, under our feet.  Like a dark cloud of volcanic ash circling the globe, we stifle and kill species on a massive scale in not much less sudden a fashion.  Even when we keep our hands clean, we contribute to global warming, pollution, and deforestation just by maintaining a modern lifestyle.  We are a mass extinction event, and we are still unfolding.</p> <p>But as we know, mass extinctions are not the end of the world, and on the contrary, they offer new beginnings for life on Earth.  Whether humanity remains a part of that life remains to be seen.  Complex, intelligent life has evolved from rudimentary beginnings before and can do so again.  And as one of the largest biomasses on the planet, humanity could speciate in the wake of ecological collapse and fragmentation.  How we evolve could surpass our wildest dreams.</p> <p>But I like being human, and I consider our world a beautiful place, one worth savoring and not throwing away.  Unlike any natural disaster we have the gift of agency and choice, of intelligence, foresight, and decision.  We are coming to terms with a small world that is getting smaller, and we will surely react and adapt to this knowledge as best we can.  But no outcome is inevitable.  All action and inaction will have an impact.  If we want to remain who we believe ourselves to be, we must choose to respect life, to value and foster diversity, to just take it easy once in a while, to control our primal appetites, and to change our very nature.  Only by choosing to change, rather than having to change, can we truly stay human.</p> <p><em>Reposted from August 13, 2013</em></p> </div> <span><a title="View user profile." href="/author/milhayser">milhayser</a></span> <span>Tue, 10/17/2017 - 06:43</span> <div class="field field--name-field-blog-categories field--type-entity-reference field--label-inline"> <div class="field--label">Categories</div> <div class="field--items"> <div class="field--item"><a href="/channel/life-sciences" hreflang="en">Life Sciences</a></div> </div> </div> Tue, 17 Oct 2017 10:43:48 +0000 milhayser 69288 at The Great Pacific Invasion <span>The Great Pacific Invasion</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><p>When the big tsunami hit Japan in 2011, many objects were washed out to sea. This flotsam provided for a giant "rafting event." A rafting event is when animals, plants, etc. float across an otherwise uncrossable body of water and end up alive on the other side. With this particular event, I don't think very many terrestrial life forms crossed the Pacific, but a lot of littoral -- shore dwelling and near shore -- animals and plants did. </p> <p>Even though the Pacific ocean is one big puddle and you would think that any organism anywhere in it could just go to any other part of the ocean, like in the movie Finding Nemo, that simply isn't true, and many organisms, most, don't migrate at all and don't disperse that far. </p> <p>This video gives an overview of the dispersal of Japanese marine life forms across the pacific.</p> <iframe width="560" height="315" src="" frameborder="0" allowfullscreen=""></iframe><p> One might assume that this sort of rafting event happens all the time, or at least, every century or so when there is a tsunami. Partly true. But the flotsam that flotsamized the Pacific this time around included a lot of stuff that did not, could not, rot, and had generally more chance of making it all the way before floating.</p> <p>And, of course, this is all being <a href="">studied by scientists</a> because it is an amazing opportunity. From the abstract of a paper just out:</p> <blockquote><p>The 2011 East Japan earthquake generated a massive tsunami that launched an extraordinary transoceanic biological rafting event with no known historical precedent. We document 289 living Japanese coastal marine species from 16 phyla transported over 6 years on objects that traveled thousands of kilometers across the Pacific Ocean to the shores of North America and Hawai‘i. Most of this dispersal occurred on nonbiodegradable objects, resulting in the longest documented transoceanic survival and dispersal of coastal species by rafting. Expanding shoreline infrastructure has increased global sources of plastic materials available for biotic colonization and also interacts with climate change–induced storms of increasing severity to eject debris into the oceans. In turn, increased ocean rafting may intensify species invasions.</p></blockquote> <p>Carlton, James, et. al 2017. Tsunami-driven rafting: Transoceanic species dispersal and implications for marine biogeography. <a href="">Science 357:6358(1402-2406)</a></p> </div> <span><a title="View user profile." href="/author/gregladen">gregladen</a></span> <span>Thu, 09/28/2017 - 10:30</span> <div class="field field--name-field-blog-categories field--type-entity-reference field--label-inline"> <div class="field--label">Categories</div> <div class="field--items"> <div class="field--item"><a href="/channel/life-sciences" hreflang="en">Life Sciences</a></div> </div> </div> Thu, 28 Sep 2017 14:30:49 +0000 gregladen 34541 at Attempts to save Houston's bats <span>Attempts to save Houston&#039;s bats</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><p><a class="irc_mil i3597 ifOHA3TJ761c-zixyDjKkw5M" tabindex="0" href=";rct=j&amp;q=&amp;esrc=s&amp;source=images&amp;cd=&amp;cad=rja&amp;uact=8&amp;ved=0ahUKEwj25dSTmf7VAhWILmMKHZOGCasQjRwIBw&amp;;psig=AFQjCNEeRSC_m-3lrB1qYN2xreNm8JwG0A&amp;ust=1504156335317525" target="_blank" rel="noopener noreferrer" data-ved="0ahUKEwj25dSTmf7VAhWILmMKHZOGCasQjRwIBw" data-noload="" data-cthref="/url?sa=i&amp;rct=j&amp;q=&amp;esrc=s&amp;source=images&amp;cd=&amp;cad=rja&amp;uact=8&amp;ved=0ahUKEwj25dSTmf7VAhWILmMKHZOGCasQjRwIBw&amp;;psig=AFQjCNEeRSC_m-3lrB1qYN2xreNm8JwG0A&amp;ust=1504156335317525" data-ctbtn="2"><img class="irc_mi" src="" alt="Image result for mexican free-tailed bat wikimedia" width="473" height="315" /></a></p> <div id="main" data-jiis="cc"> <div id="cnt" class="big"> <div id="rcnt"> <div class="col"> <div id="center_col"> <div id="res" class="med"> <div id="search" data-jiis="uc" data-jibp="h"> <div data-ved="0ahUKEwjVv7qRmf7VAhUB-mMKHaU3B4IQGggj"> <div id="ires" data-async-context="query:mexican%20free-tailed%20bat%20wikimedia"> <div id="rso"> <div id="isr_mc"> <div id="irc_bg" class="irc_bg irc_land"> <div id="_YTc"> <div id="irc_cc"> <div class="irc_c i8187 immersive-container" data-item-id="SY5QRsTkV2-LQM:" data-ved="0ahUKEwj25dSTmf7VAhWILmMKHZOGCasQ-z8IEg" data-hveid="18"> <div class="irc_t i30052" data-ved="0ahUKEwj25dSTmf7VAhWILmMKHZOGCasQ5OoBCBM" data-hveid="19" data-noload=""> <div class="irc_mic r-ifOHA3TJ761c"> <div class="irc_mimg irc_hic ifOHA3TJ761c-lvVgf-rIiHk">By U.S. Fish and Wildlife Service Headquarters [CC BY 2.0 (<a href=""></a>) or Public domain], via Wikimedia Commons</div> </div> </div> <div class="irc_mimg irc_hic ifOHA3TJ761c-lvVgf-rIiHk"></div> </div> </div> </div> </div> </div> </div> </div> </div> </div> </div> </div> </div> </div> </div> </div> <p>Got bugs? Get a bat. As many species of bats are insectivores, they help keep insect populations in check. Hurricane Harvey has been devastating to people, animals and property. So it probably comes as no surprise that there are many volunteers dedicating their time to saving animals displaced by Hurricane Harvey as well. From squirrels, cats and dogs guessed it...bats. It turns out that bats are not very good swimmers.  The <a href="">Waugh Bridge</a> is home to a population of roughly 250,000 Mexican free-tailed bats that became stranded with the rising floodwaters. Witnessing dead and struggling bats in the waters, volunteers worked hard to try to rescue as many bats as possible using any means available including umbrellas, branches, tennis rackets, nets, etc.</p> <p>Each night these bats consume about 2.5 tons of insects. In the aftermath of the flood, insects like mosquitoes are expected to proliferate along with the diseases they carry. With such large appetites, existence without bats would be pretty buggy.</p> <p><strong>Source:</strong></p> <p><a href="">CBS News</a></p> </div> <span><a title="View user profile." href="/author/dr-dolittle">dr. dolittle</a></span> <span>Tue, 08/29/2017 - 19:26</span> <div class="field field--name-field-blog-categories field--type-entity-reference field--label-inline"> <div class="field--label">Categories</div> <div class="field--items"> <div class="field--item"><a href="/channel/life-sciences" hreflang="en">Life Sciences</a></div> </div> </div> Tue, 29 Aug 2017 23:26:07 +0000 dr. dolittle 150517 at Comments of the Week #174: from growing black holes to nuclear bombs <span>Comments of the Week #174: from growing black holes to nuclear bombs</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><blockquote><p>“It will shine still brighter when night is about you. May it be a light to you in dark places, when all other lights go out.” ―Galadriel, LOTR, J.R.R. Tolkien</p></blockquote> <p>Well, we've been anticipating it for months (or years), but this is our very first time meeting up since the total solar eclipse here at <a href="">Starts With A Bang!</a> Did you get to see it? Was it as spectacular for you as it was for me? I'm already looking forward to 2024, but you can look forward to a podcast coming this next week from me on just how spectacular it was! (With a judicious dose of physics and astrophysics, of course.) <a href="">Patreon supporters</a>, of course, can get it right now; no waiting! With that said, let's move on to the scientific stories we covered this past week:</p> <ul><li><a href="" target="_blank" rel="noopener noreferrer">Do black holes grow faster than they evaporate?</a> (for Ask Ethan),</li> <li><a href="" target="_blank" rel="noopener noreferrer">The hottest stars in the Universe are all missing one key ingredient</a> (for Mostly Mute Monday),</li> <li><a href="" target="_blank" rel="noopener noreferrer">Ten Surprises For Scientists And Skywatchers During The Total Solar Eclipse</a>,</li> <li><a href="" target="_blank" rel="noopener noreferrer">Beyond black holes: could LIGO have detected merging neutron stars for the first time?</a>,</li> <li><a href="" target="_blank" rel="noopener noreferrer">Afraid of aliens? The science doesn't back you up</a>, and</li> <li><a href="" target="_blank" rel="noopener noreferrer">Science knows if a nation is testing nuclear bombs</a>.</li> </ul><p>I seriously can't believe that the publication of my latest book, <a href="">Treknology</a>, is almost upon us. And -- if you didn't catch it -- I actually had <a href="">my first op-ed, cowritten with Alex Berezow, appear in the Wall Street Journal</a>! This year's going to end with a bang, too, I can feel it! And now that we've covered all that, let's dive right into what you had to say for our <a href="">comments of the week</a>!</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/07/TSE_2016_srd.jpg"><img class="size-medium wp-image-36392" src="/files/startswithabang/files/2017/07/TSE_2016_srd-600x606.jpg" alt="" width="600" height="606" /></a> 32 images of the 2016 eclipse were combined in order to produce this composite, showcasing not only the corona and the plasma loops above the photosphere with stars in the background, but also with the Moon's surface illuminated by Earthshine. Image credit: Don Sabers, Ron Royer, Miloslav Druckmuller. </div> <p>From <a href="">Ragtag Media</a> on a good way to celebrate the eclipse: "If’s you want a great souvenir to pass on, the US postal service is selling some cool eclipse stamps:<br /><a href="" rel="nofollow"></a>"</p></blockquote> <p>I agree with Ragtag here. I bought a couple of sheets of these and they're wonderful. They look, to be honest, like Miloslav Druckmuller's photos (above), and I've already sent a few off to some lucky folks. Now that I've seen one for the first time, I'm a true believer in their magnificence, and I can't wait for the next one!</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/08/starlightDeflectionFig3.jpg"><img class="size-medium wp-image-36525" src="/files/startswithabang/files/2017/08/starlightDeflectionFig3-600x565.jpg" alt="" width="600" height="565" /></a> The Newtonian and Einsteinian predictions for gravitational deflection of a distant radio source during the Earth's orbital period (1 year) due to the Sun. The black dots are 2015 data. Image credit: The deflection of light induced by the Sun's gravitational field and measured with geodetic VLBI; O. Titov, A. Girdiuk (2015). </div> <p>From <a href="">Anonymous Coward</a> on confirming relativity without waiting for an eclipse: "Thanks Ethan, for the indirect link. That picture and its caption was a big enough clue for me to find the paper by Titov and Girdiuk: “The deflection of light induced by the Sun’s gravitational field and measured with geodetic VLBI.” I’d heard about the radio measurements of light deflection from the sun but didn’t know of any primary sources."</p></blockquote> <p>It is incredible how much amazing, quality science has gone on with regards to confirming relativity. In addition to light-bending by the Sun, we do have confirmation of gravitational redshift, the Shapiro time delay, the precession of not just Mercury's orbit but also Venus', Earth's, and Mars' orbits, the Lens-Thirring effect, geodetic precession, strong and weak gravitational lensing, the Sachs-Wolfe and Integrated Sachs-Wolfe effect, and many others, not the least of which is the direct detection of gravitational waves by LIGO. General relativity is extraordinarily well-confirmed by a whole slew of independent lines of evidence -- Govert's book <em><a href="">Ripples In Spacetime</a></em> that I <a href="">reviewed just recently</a> -- does a wonderful job recounting many of the confirmations. The radio VLBI observations are a good, recent one that I'm happy I can point you towards. Interestingly, many people have worked to take observations, independently, good enough to confirm the original Eddington experiment this past Monday. I'll let you know if I come across any robust results.</p> <div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2016/03/25848795491_10c9cfe4f2_k.jpg"><img class="size-medium wp-image-34381" src="/files/startswithabang/files/2016/03/25848795491_10c9cfe4f2_k-600x617.jpg" alt="" width="600" height="617" /></a> Image credit: photograph by Frank Tuttle of King Triton and Ursula the sea witch from the Little Mermaid at MidSouthCon 34. </div> <blockquote><p>From <a href="">Steve Blackband</a> on who am I: "BTW is the guy in the grey beard and crown you?"</p></blockquote> <p>Updated annually since 2009 with each new Halloween photo. If you missed any, they've been:</p> <ul><li>2016: King Triton,</li> <li>2015: Axe Cop,</li> <li>2014: Man-o-taur,</li> <li>2013: Rainbow Dash,</li> <li>2012: Zangief,</li> <li>2011: Wolverine,</li> <li>2010: Macho Man Randy Savage,</li> <li>2009: Pharaoh Ramses.</li> </ul><p>Keep speculating as to what 2017 might hold!</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/08/Illustration_of_a_black_hole_and_its_surrounding_disk-1200x960.jpg"><img class="size-medium wp-image-36519" src="/files/startswithabang/files/2017/08/Illustration_of_a_black_hole_and_its_surrounding_disk-1200x960-600x479.jpg" alt="" width="600" height="479" /></a> As a black hole shrinks in mass and radius, the Hawking radiation emanating from it becomes greater and greater in temperature and power. Once the decay rate exceeds the growth rate, Hawking radiation only increases in temperature and power. Image credit: NASA. </div> <p>From <a href="">Omega Centauri</a> on what Hawking radiation is made of: "Since we have a primordial neutrino background at IIRC 1.75K, do black holes also emit Hawking like neutrino radiation? Or does finite rest mass largely suppress this?"</p></blockquote> <p>We normally think of Hawking radiation as being radiation (photons) only, and to a first approximation, that's very likely correct. Why? Because we don't have enough power in the radiation to -- as you intuit -- create any particles with non-zero rest mass. Even the rest mass of a neutrino, at the low end at around 10^-6 eV/c^2, is far too great to be created by any black holes that exist today. (The CNB is around 1.95 K, FYI, but falling into gravitational wells leads to greater velocity than that temperature would imply.)</p> <p>Give it enough time, though; when the mass of a black holes shrinks to a small enough value so that the temperature of Hawking radiation is above the neutrino rest mass energy, or above a few tens of Kelvin, and you'll start making neutrinos, then electron/positron pairs, and then the really heavy stuff in the last few seconds. What's interesting is that we're still not sure what sort of gravitational waves come out at the event horizon, as we don't have the quantum theory of gravity necessary to go there. Too bad, because gravitons are massless, too!</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/06/LIGOsound.jpg"><img class="size-medium wp-image-36276" src="/files/startswithabang/files/2017/06/LIGOsound-600x451.jpg" alt="The 30-ish solar mass binary black holes first observed by LIGO are likely from the merger of direct collapse black holes. But a new publication challenges the analysis of the LIGO collaboration, and the very existence of these mergers. Image credit: LIGO, NSF, A. Simonnet (SSU)." width="600" height="451" /></a> The 30-ish solar mass binary black holes first observed by LIGO are likely from the merger of direct collapse black holes. But a new publication challenges the analysis of the LIGO collaboration, and the very existence of these mergers. Image credit: LIGO, NSF, A. Simonnet (SSU). </div> <p>From <a href="">Michael Mooney</a> on an intended insult that's actually a compliment: "Ethan consistently makes statements as established facts even though they are theoretical, without empirical evidence and surrounded by debate in the world of physics."</p></blockquote> <p>Yes, you're very welcome. What you are talking about is called "theoretical physics," in the sense that we have theories which accurately describe the Universe, which in turn we can use to make predictions about new phenomena that haven't yet been observed. It is the best, most straightforward use of theoretical physics, and also my favorite: it's what I built the start of my career on. It's why we were able to predict gravitational waves, including their properties and waveforms, before we had ever detected them. It's why a whole slew of science is able to be done at all.</p> <p>Someday, like many others before you, you may come to appreciate it.</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/05/1-JfanY_MplBJ_FX1N0I2StQ-1200x675.jpg"><img class="size-medium wp-image-36161" src="/files/startswithabang/files/2017/05/1-JfanY_MplBJ_FX1N0I2StQ-1200x675-600x337.jpg" alt="" width="600" height="337" /></a> Hawking radiation is what inevitably results from the predictions of quantum physics in the curved spacetime surrounding a black hole's event horizon. Image credit: E. Siegel. </div> <p>From <a href="">klac</a> on what a black hole's event horizon looks like: "Is the “surface” of the event horizon smooth or roiling? If the latter, does this affect the evaporation rate?"</p></blockquote> <p>Smooth, down to the quantum gravity scale. At the scale at which it is imperfect, there will be imperfections in the spectrum of Hawking radiation. If Hawking radiation is ever detectable, the fluctuations will be another 30-something orders of magnitude below that in scale. Good luck.</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/08/WR_31a.jpg"><img class="size-medium wp-image-36522" src="/files/startswithabang/files/2017/08/WR_31a-600x450.jpg" alt="This Wolf–Rayet star is known as WR 31a, located about 30 000 light-years away in the constellation of Carina. The outer nebula is expelled hydrogen and helium, while the central star burns at over 100,000 K. Image credit: ESA/Hubble &amp; NASA; Acknowledgement: Judy Schmidt." width="600" height="450" /></a> This Wolf–Rayet star is known as WR 31a, located about 30 000 light-years away in the constellation of Carina. The outer nebula is expelled hydrogen and helium, while the central star burns at over 100,000 K. Image credit: ESA/Hubble &amp; NASA; Acknowledgement: Judy Schmidt. </div> <p>From <a href="">John</a> on Wolf-Rayet stars: "These Wolf-Rayet stars would make for a pretty inhospitable Solar System!"</p></blockquote> <p>Oh, yes! That is an extremely good point; here are just a few reasons why:</p> <ul><li>They only live for maybe a few million years before they end their lives,</li> <li>They change in luminosity by a factor of many over that time,</li> <li>They blow off many solar masses worth of plasma across any planets present,</li> <li>They are unstable, flaring stars,</li> <li>And their spectra are such that they ought to strip the atmospheres off of any potentially habitable world that ever existed around them.</li> </ul><p>I would say that makes for "pretty inhospitable" indeed.</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2016/06/Oxford_-_Worcester_College_-_garden_tree_sunbeam.jpg"><img class="size-medium wp-image-34760" src="/files/startswithabang/files/2016/06/Oxford_-_Worcester_College_-_garden_tree_sunbeam-600x450.jpg" alt="" width="600" height="450" /></a> Sunbeams shining through the trees at Oxford, by Wikimedia Commons user Remi Mathis, under a c.c.a.-by-s.a.-3.0 license. </div> <p>From <a href="">CFT</a> on the solar eclipse: "I can get the effect of a complete solar eclipse every time I walk under a leafy tree or enter my house. I call it ‘shade’."</p></blockquote> <p>Walking under a shady tree is to a total solar eclipse what fanning yourself with a folded sheet of paper is to skydiving for the first time. Never seen a total solar eclipse? I highly recommend it; it just might change your outlook on life a little bit.</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/08/960x0.jpg"><img class="size-medium wp-image-36549" src="/files/startswithabang/files/2017/08/960x0-600x517.jpg" alt="" width="600" height="517" /></a> A shot of the Sun's corona at the moment of totality, during the Great American Eclipse of August 21, 2017, at Casper Collage Wyoming. Image credit: Gene Blevins/AFP/Getty Images. </div> <p>From <a href="">Sinisa Lazarek</a> on eclipse surprises: "Reading your article it’s clear that you had a blast and that you’re still under emotional experience of it. ? I’m glad and happy that you had good weather and that it was great.<br /> But can’t really understand why points 1, 2, 6 and 9 are surprising, especially for scientists."</p></blockquote> <p>Well, the first one (that it didn't get dark all at once) surprised me, because the Sun is really, really bright, and a penumbral shadow is kind of (no offense to the inanimate objects in the Solar System) garbage compared to the umbral shadow when it falls on the Moon. When total eclipses happen under cloudy conditions -- which is how the people I know experienced the 1979 eclipse -- it does get dark all at once. So that's why #1 surprised me.</p> <p>The second one, as to the size and brightness of the corona, I had only seen photos. Sure, some photos are long-exposure to bring out the detail in the outer corona, but I had expected to see a much smaller corona, akin to what the photo at the very top of the page showed, than what was actually visible to my eye. There's no way to really know these things for sure, that cannot be preserved on film, until you've experienced it for yourself. Being a scientist has very little to do with the human experience you feel with your own body. In more than a theoretical sense alone, we all need to live.</p> <div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/08/solar_disk.png"><img class="size-full wp-image-36550" src="/files/startswithabang/files/2017/08/solar_disk.png" alt="" width="600" height="422" /></a> The eclipsed Sun, the visible corona, and the surrounding sky, as blown-up by me multiple times over the original image referenced. Image credit: Joe Sexton / Jesse Angle. </div> <blockquote><p>From <a href="">Pawel</a> on why the Moon's shadow is so black: "But the question is – why the Moon seems so black during totality? The rest of the sky, beyond the Sun’s corona, is bright because of the light refracted in the atmosphere. Since the Moon is far beyond the atmosphere, shouldn’t it be washed away by the refracted light and appear the same color as the rest of the sky?"</p></blockquote> <p>Optics never fails to disappoint with how interesting it is. Here's a fun thing for you to do: draw yourself a to-scale diagram (it's tough!) of the Sun, the Moon, and the Earth. Now, extend the Sun's radius by, oh, let's say about 40%, just for giggles. Draw those same lines you'd draw for the Corona's shadow -- both umbral and penumbral -- that you'd draw for the Sun's shadow.</p> <p>If you do, you'll see how much <em>less</em> coronal light gets through at the Moon's center than at the surrounding environs. That's the biggest reason why the Moon's disk appears dark in comparison to the region outside the Moon's disk, even when you're away from the visible corona itself.</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/08/eclipse-1200x667.jpg"><img class="size-medium wp-image-36551" src="/files/startswithabang/files/2017/08/eclipse-1200x667-600x333.jpg" alt="" width="600" height="333" /></a> A simulated picture of the sky as it might have appeared during the total solar eclipse of August 21st. Regulus (next to the Sun), Mars (top) and Mercury (bottom) may all be visible with clear skies and favorable conditions. Image credit: E. Siegel / Stellarium. </div> <p>From <a href="">Steve Blackband</a> on whether he saw Mars or not: "BTW I was starring hard, but I was pretty sure I saw Mars, close to and to the left of the sun, at about 11 o-clock. Am I deluded?"</p></blockquote> <p>No, but if it was to the <em>left</em> (east?) of the Sun, it was probably Mercury. If it was to the <em>right</em> (west) of the Sun, it could have been Mars. If it was either of those, they should have been about 12 degrees (throw heavy metal horns with your index and pinkie fingers, held at arm's length) off from the Sun. If it was much more than that, it was probably Jupiter (to the left) or Venus (bright, to the right), while if it was only about 1 degree off from the Sun, that was probably Regulus.</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/07/Total-solar-eclipse-illustration.jpg"><img class="size-medium wp-image-36430" src="/files/startswithabang/files/2017/07/Total-solar-eclipse-illustration-600x450.jpg" alt="" width="600" height="450" /></a> An illustration of the Sun-Moon-Earth configuration setting up a total solar eclipse. The Earth's non-flatness means that the Moon's shadow gets elongated when it's close to the edge of the Earth. Image credit: Starry Night education software. </div> <p>From <a href="">PJ</a> on eclipse mania: "Welcome to the club, Ethan. You seem to show the signs. More, more! Next eclipse, please! At least the next one will see you better prepared now you have first hand experience of the event."</p></blockquote> <p>2024, totality in the USA, and it should be more than twice as long as what I got to see. (Waco, TX, gets 4:15 of totality, while in Mexico they get to over 4:30.) If I get really ambitious, there's always the 2027 eclipse, just shy of my 50th birthday, which will go over the Iberian Peninsula and then peak near Luxor, Egypt. Maximum totality there is over 6 minutes, and should be among the most spectacularly dark eclipses of the 21st century.</p> <p>Yes, PJ, I've had my first taste and now... well, you know how I teach electric potential energy in college? Bringing in electric charges is like the crack dealer: the first one's free, but the second one costs you, and then subsequent ones cost more and more... and you'll pay it if you want it bad enough!</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/03/merger.jpg"><img class="size-medium wp-image-35936" src="/files/startswithabang/files/2017/03/merger-600x301.jpg" alt="" width="600" height="301" /></a> As two neutron stars orbit each other, Einstein's theory of general relativity predicts orbital decay, and the emission of gravitational radiation. Image credit: NASA (L), Max Planck Institute for Radio Astronomy / Michael Kramer. </div> <p>From <a href="">Omega Centauri</a> on the possible types of gravitational wave signals: "I presume expected signals, gravity-wave, optical/X-ray, etc. have been worked out for the different sorts of compact object merger events.<br /> BH v BH<br /> BH v NS<br /> BH v WD<br /> NS v NS<br /> NS v WD"</p></blockquote> <p>Well, here's the thing: the above signal that you see works for all objects as long as they're spherical and not in physical contact with one another. But white dwarfs, about the size of Earth, touch each other (or whatever they're orbiting) way before something like LIGO would be sensitive to them. LIGO will not see white dwarfs.</p> <p>On the other hand, BH-BH mergers, BH-NS mergers, and NS-NS mergers have all been very thoroughly modeled. NS-NS mergers, in particular, are expected to produce gamma-ray bursts and leave the signatures I described to you in the article from this week. Are they correct, these predicted signatures? I have a feeling there will be a lot more to come on this topic as the coming weeks unfold...</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2015/01/1-18-Brightness-Distance.jpg"><img class="size-medium wp-image-32321" src="/files/startswithabang/files/2015/01/1-18-Brightness-Distance-600x295.jpg" alt="" width="600" height="295" /></a> The brightness/distance relation for light, which is not the same as for gravitational waves. Image credit: E. Siegel. </div> <p>From <a href="">Klavs Hansen</a> on the unbearable lack-of-lossiness in gravitational wave astronomy: "A factor ten reduction in energy means that the event needs to be a factor ten closer to be detected?"</p></blockquote> <p>Yup. And it isn't obvious. Light, an electromagnetic effect, is a form of dipole radiation. If you go twice as far away, the brightness dims to one-fourth the original; if you're ten times as far away, the brightness is 1/100th. But gravitational radiation is <em>quadrupolar</em> radiation, not dipole radiation. It doesn't fall off as 1/r^2, but rather as 1/r. If you're ten times as far away, the magnitude is only 1/10th as great. This is good, because that radiation is so weak! It also means, if you wanted to visually detect what was going on with the original merging black holes that LIGO found, they'd need to have merged from within our Solar System, instead of over a billion light years away. There is no good non-technical explanation of this effect that I've yet figured out that's actually still correct.</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/08/8298924277_f2f7634ca2_b.jpg"><img class="size-medium wp-image-36537" src="/files/startswithabang/files/2017/08/8298924277_f2f7634ca2_b-600x400.jpg" alt="" width="600" height="400" /></a> Our fear of aliens, and their potential hostility towards humanity, has driven much of our public sentiment and presentation of extraterrestrial life. Image credit: plaits / flickr. </div> <p>From <a href="">eric</a> on disagreeing about alien intents: "Consider the species on Earth with reasonably sized brains. most of them can communicate (albeit not like we do). All of them are more closely related to humans in brain structure, instinct, and emotional desires than any alien we will ever meet – hands down, no contest. And yet <i>practically none of them show any interest in wanting to communicate with humans</i>."</p></blockquote> <p>Huh. I suppose we've met different intelligent animals. Dogs, cats, dolphins, monkeys, Orang Utans... I've met <em>lots</em> of animals that not only want to communicate with humans in general (and me in particular), but that want us to play with them. Play is one of the highest forms of communication, IMO, so... my experience doesn't mirror yours, I suppose.</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/08/Atomic_cloud_over_Nagasaki_from_Koyagi-jima.jpg"><img class="size-medium wp-image-36543" src="/files/startswithabang/files/2017/08/Atomic_cloud_over_Nagasaki_from_Koyagi-jima-600x464.jpg" alt="The cloud from the atomic bomb over Nagasaki from Koyagi-jima in 1945 was one of the first nuclear detonations to take place on this world. After decades of peace, North Korea is detonating bombs again. Credit: Hiromichi Matsuda." width="600" height="464" /></a> The cloud from the atomic bomb over Nagasaki from Koyagi-jima in 1945 was one of the first nuclear detonations to take place on this world. After decades of peace, North Korea is detonating bombs again. Credit: Hiromichi Matsuda. </div> <p>And finally, from <a href="">Elle H.C.</a> on the nuclear frontier and mass-energy conversion: "Is nuclear energy the last barrier where mass can be turned into energy, no sub-atomic conversion to worry about, anyone have a crystal ball to foresee ‘the future’?"</p></blockquote> <p>Oh no, not at all. You see, even chemical transitions, where electrons hop from one energy level to another, get their energy from mass-energy conversion. It's just 5-6 orders of magnitude less efficient. But in the other direction, matter-antimatter annihilation (or, in the case of boson-boson interaction, pure annihilation with no distinction between matter and antimatter) is 100% efficient, about 2-3 orders of magnitude better than nuclear energy. It's pretty incredible what we've achieved, but there are reminders that nature is both more subtle than we give it credit for and also capable of being more spectacular than anything we've ever yet made come true.</p> <p>Have a wonderful week, and we'll be back here tomorrow with more outstanding science on Starts With A Bang!</p> </div> <span><a title="View user profile." href="/author/esiegel">esiegel</a></span> <span>Sun, 08/27/2017 - 03:37</span> <div class="field field--name-field-blog-categories field--type-entity-reference field--label-inline"> <div class="field--label">Categories</div> <div class="field--items"> <div class="field--item"><a href="/channel/life-sciences" hreflang="en">Life Sciences</a></div> </div> </div> Sun, 27 Aug 2017 07:37:38 +0000 esiegel 37080 at Starting from scratch, creating a complete pox virus <span>Starting from scratch, creating a complete pox virus</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><p>People talk about resurrecting the Mammoth, the Dodo, the Quagga, or the Tasmanian devil, or any number of extinct (or mostly extinct) creatures. I'm all for that. I suggest removing cattle farming in Nebraska, Wyoming, Montana and adjoining areas of Canada, and repopulating the region with extinct megafauna. That would just be cool. </p> <p>There are difficulties with this, including figuring out exactly how to piece together the genome for the extinct animal, how to get a good level of genetic diversity in the neo-founding population, and how to raise the critter up from a zygote. For all these reasons, I've always thought we should start by resurrecting something that already exists. We normally do this sort of dry run or practice run with things we do. In baseball, golf, and other ball sports, athletes take pre-swings. We went "to" the moon a couple of times before landing "on" the moon. Etc. So, let's start by resurrecting a fruit fly, them maybe a chicken, then a dog. That sort of thing.</p> <p>A potentially important public health concern is the re-emergence, one way or another, of small pox or something like small pox. In order to manage that, we would like to see more research involving vaccines. An ideal way to carry out vaccine research without risking the release of full blown small pox (which may or may not be frozen somewhere) on the population is to create a small pox virus (small pox is a virus) from scratch, using a known genetic code. In so doing, the parts of the virus that allow it to spread could be denatured, and the parts of the virus that allow research for vaccines or cures could be left in place. </p> <p>In essence, creating such a Frankensteinian life form is like resurrecting an extinct species. And, some Canadian scientists stole my idea and went ahead and resurrected a non-extinct species in order to test out the plausibility of the method. The research is not published and likely won't be, because it would be too easily misused by nefarious actors. But, the results were discussed at <a href="">a meeting</a> several months ago, and now there is something new about it in <a href="">Science</a>:</p> <blockquote><p>Eradicating smallpox, one of the deadliest diseases in history, took humanity decades and cost billions of dollars. Bringing the scourge back would probably take a small scientific team with little specialized knowledge half a year and cost about $100,000.</p> <p>That’s one conclusion from an unusual and as-yet unpublished experiment performed last year by Canadian researchers. A group led by virologist David Evans of the University of Alberta in Edmonton, Canada, says it has synthesized the horsepox virus, a relative of smallpox, from genetic pieces ordered in the mail. ...</p></blockquote> <p>The story is also covered by the<a href=";wpisrc=al_alert-hse&amp;wpmk=1"> Washington Post</a>. </p> <p>And, here is a previously released press release:</p> <blockquote><p><strong>Tonix Pharmaceuticals Announces Demonstrated Vaccine Activity in First-Ever Synthesized Chimeric Horsepox Virus</strong></p> <p><em>Pre-Clinical Smallpox-Preventing Vaccine Candidate TNX-801 May Qualify for Priority Review Voucher if FDA-Approved Under Provisions in the 21st Century Cures Act</em></p> <p><strong>NEW YORK, March 02, 2017 (GLOBE NEWSWIRE) --</strong> Tonix Pharmaceuticals Holding Corp. (Nasdaq:TNXP) (Tonix), a company that is developing innovative pharmaceutical products to address public health challenges, working with researchers from the University of Alberta, a leading Canadian research university, today announced the successful synthesis of a potential smallpox-preventing vaccine. This vaccine candidate, TNX-801, is a live form of horsepox virus (HPXV) that has been demonstrated to have protective vaccine activity in mice. </p> <p>“Presently, the safety concern of existing smallpox-preventing vaccines outweigh the potential benefit to provide immunization of first responders or the general public. By developing TNX-801 as a horsepox vaccine to prevent smallpox infection, we hope to have a safer vaccine to protect against smallpox than is currently available,” stated Seth Lederman, M.D., president and chief executive officer of Tonix. “Vaccines are a critical component of the infrastructure of global public health. Vaccination protects those who are vaccinated and also those who are not vaccinated, by decreasing the risk of contagion.” </p> <p>“Our goal is to improve on current methods that protect the public from possible viral outbreaks,” said Professor David Evans, Ph.D., FCAHS, Professor and Vice-Dean (Research), Faculty of Medicine and Dentistry at the University of Alberta, in Edmonton, Alberta, Canada, and principal investigator of the TNX-801 research project. </p> <p>HPXV was synthesized by Professor Evans and Research Associate Ryan Noyce, Ph.D., at the University of Alberta, with Dr. Lederman as co-investigator of the research and co-inventor of the TNX-801 patent. Under their research and development agreement, Tonix wholly owns the synthesized HPXV virus stock and related sequences. Professor Evans and Dr. Noyce also demonstrated that HPXV has protective vaccine activity in mice, using a model of lethal vaccinia infection. Vaccine manufacturing activities have been initiated by Tonix to support further nonclinical testing of TNX-801. </p> <p>Dr. Lederman stated, “Our research collaboration is dedicated to creating tools and innovative products that better protect public health.” </p> <p>About Horsepox (HPXV) and Smallpox </p> <p>Horsepox, an equine disease caused by a virus and characterized by eruptions in the mouth and on the skin, is believed to be eradicated. No true HPXV outbreaks have been reported since 1976, at which time the United States Department of Agriculture obtained the viral sample used for the sequence published in 2006 that allowed the synthesis of TNX-801. In 1798, Dr. Edward Jenner, English physician and scientist, speculated that smallpox is a human version of pox diseases in animals. Jenner had a strong suspicion that his vaccine began as a pox disease in horses and went on to show that it could be used to vaccinate against smallpox. Smallpox was eradicated as a result, and no cases of naturally occurring smallpox have been reported since 1977. Jenner’s vaccine appears to have evolved considerably in the vaccinia stocks maintained in different countries around the world, since vaccinia was mostly selected for growth and production. Being able to provide safe and effective smallpox-preventing vaccines remains important and necessary for addressing and protecting public health. </p> <p>About the Material Threat Medical Countermeasures Provisions in the 21st Century Cures Act </p> <p>In 2016, the 21st Century Cures Act (Act) was signed into law to support ongoing biomedical innovation. One part of the Act, Section 3086, is aimed at “Encouraging Treatments for Agents that Present a National Security Threat.” This section of the Act created a new priority review voucher program for “material threat medical countermeasures.” The Act defines such countermeasures as drugs or vaccines intended to treat biological, chemical, radiological, or nuclear agents that present a national security threat, or to treat harm from a condition that may be caused by administering a drug or biological product against such an agent. The priority review vouchers are awarded at the time of FDA approval and are fully transferrable and may be sold to other companies to be used for priority review of any New Drug Application (NDA) or Biologic Licensing Application (BLA). </p> <p>About Tonix Pharmaceuticals Holding Corp. </p> <p>Tonix is developing innovative pharmaceutical products to address public health challenges, with TNX-102 SL in Phase 3 development for posttraumatic stress disorder (PTSD). TNX-102 SL is designed for bedtime use and is believed to improve overall PTSD symptoms by improving sleep quality in PTSD patients. PTSD is a serious condition characterized by chronic disability, inadequate treatment options especially for military-related PTSD and overall high utilization of healthcare services creating significant economic burden. TNX-102 SL was recently granted Breakthrough Therapy designation by the FDA for the treatment of PTSD. Other development efforts include TNX-601, a clinical candidate at Pre-IND (Investigational New Drug) application stage, designed for daytime use for the treatment of PTSD, and TNX-801, a potential smallpox-preventing vaccine. </p> <p>*TNX-102 SL (cyclobenzaprine HCl sublingual tablets) is an investigational new drug and has not been approved for any indication. </p> <p>This press release and further information about Tonix can be found at <a href=""></a>. </p> <p>Forward Looking Statements </p> <p>Certain statements in this press release are forward-looking within the meaning of the Private Securities Litigation Reform Act of 1995. These statements may be identified by the use of forward-looking words such as “anticipate,” “believe,” “forecast,” “estimate,” “expect,” and “intend,” among others. These forward-looking statements are based on Tonix's current expectations and actual results could differ materially. There are a number of factors that could cause actual events to differ materially from those indicated by such forward-looking statements. These factors include, but are not limited to, substantial competition; our need for additional financing; uncertainties of patent protection and litigation; uncertainties of government or third party payor reimbursement; limited research and development efforts and dependence upon third parties; and risks related to failure to obtain FDA clearances or approvals and noncompliance with FDA regulations. As with any pharmaceutical under development, there are significant risks in the development, regulatory approval and commercialization of new products. Tonix does not undertake an obligation to update or revise any forward-looking statement. Investors should read the risk factors set forth in the Annual Report on Form 10-K for the year ended December 31, 2015, as filed with the Securities and Exchange Commission (the “SEC”) on March 3, 2016, and future periodic reports filed with the SEC on or after the date hereof. All of Tonix's forward-looking statements are expressly qualified by all such risk factors and other cautionary statements. The information set forth herein speaks only as of the date hereof.</p></blockquote> </div> <span><a title="View user profile." href="/author/gregladen">gregladen</a></span> <span>Fri, 07/07/2017 - 05:06</span> <div class="field field--name-field-blog-categories field--type-entity-reference field--label-inline"> <div class="field--label">Categories</div> <div class="field--items"> <div class="field--item"><a href="/channel/life-sciences" hreflang="en">Life Sciences</a></div> </div> </div> Fri, 07 Jul 2017 09:06:04 +0000 gregladen 34452 at Affluence Without Abundance <span>Affluence Without Abundance</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><p>My father in law is an excellent amateur mixologist. I don't drink alcohol very often, but we're all up at the cabins, so last night I had a paper plane. And I believe this is what led to a night of strange and extensive dreams, and in my dreams was my recently deceased PhD adviser, Irv DeVore. (Irv was not dead in the dream.) DeVore is famous for having initiated, with Richard Lee, the first scientific study of extant living foragers, and they worked with the Ju/'Honasi of Botswana/Namibia/South Africa. </p> <p>So, it was strange to have the lingering dream on my mind as I opened the latest Science magazine to see a review, by Alan Barnard, of a recent and interesting book on those people: <a target="_blank" href=";camp=1789&amp;creative=9325&amp;creativeASIN=1632865726&amp;linkCode=as2&amp;tag=grlasbl0a-20&amp;linkId=5450d853d8b299e3638c8219f85e9443">Affluence Without Abundance: The Disappearing World of the Bushmen</a><img src="//;l=am2&amp;o=1&amp;a=1632865726" width="1" height="1" border="0" alt="" style="border:none !important; margin:0px !important;" />.</p> <blockquote><p>A vibrant portrait of the “original affluent society”--the Bushmen of southern Africa--by the anthropologist who has spent much of the last twenty-five years documenting their encounter with modernity.</p> <p>If the success of a civilization is measured by its endurance over time, then the Bushmen of the Kalahari are by far the most successful in human history. A hunting and gathering people who made a good living by working only as much as needed to exist in harmony with their hostile desert environment, the Bushmen have lived in southern Africa since the evolution of our species nearly two hundred thousand years ago.</p> <p>In Affluence Without Abundance, anthropologist James Suzman vividly brings to life a proud and private people, introducing unforgettable members of their tribe, and telling the story of the collision between the modern global economy and the oldest hunting and gathering society on earth. In rendering an intimate picture of a people coping with radical change, it asks profound questions about how we now think about matters such as work, wealth, equality, contentment, and even time. Not since Elizabeth Marshall Thomas's The Harmless People in 1959 has anyone provided a more intimate or insightful account of the Bushmen or of what we might learn about ourselves from our shared history as hunter-gatherers.</p></blockquote> <p>Barnard says:</p> <blockquote><p>The book is full of illuminating observations from the Bushmen themselves. In one passage, for example, Suzman relates an encounter with ≠Oma, one of the resettlement community's most established residents, who once served as a foreman when Skoonheid was still a working farm: “If you are foreman,” ≠Oma tells Suzman, “then you are the eyes and the ears of the baas [boss] on the farm. You are the chief of the workers and are in charge when the baas is away.” Despite better pay and greater social standing among the white farm owners, ≠Oma never entirely succeeded in securing the respect and deference he demanded from his fellow Ju/'hoansi. Today's Bushmen are part of two worlds, one guided by the group's traditional commitment to egalitarianism and the other based on subjugation.</p> <p>In general, anthropological commentary is kept to a minimum, but Suzman's descriptions are full of insight. “To them everything in the world is natural and everything cultural in the human world is also cultural in the animal world, and ‘wild’ space is also domestic space,” he writes, for example, in chapter 7. “So while Ju/'hoansi consider the litter to be an irritation, few see it as pollution—at least in the way the tourists do.”</p> <p>Suzman's frequent reflexivity (e.g., “I never hunted with /I!ae. I was too clumsy, loud, and slow.”) makes the book far more interesting than typical accounts full of statistical detail, academic references, and the like. The book offers few references, and details are limited to those that make for good reading. There are, however, several useful (albeit simple) maps of the areas described and a brief explanation of how to pronounce clicks.</p></blockquote> <p>The review is <a href="">here</a>, but I'm not sure if you can see it without a subscription.</p> </div> <span><a title="View user profile." href="/author/gregladen">gregladen</a></span> <span>Mon, 07/03/2017 - 05:07</span> <div class="field field--name-field-blog-categories field--type-entity-reference field--label-inline"> <div class="field--label">Categories</div> <div class="field--items"> <div class="field--item"><a href="/channel/life-sciences" hreflang="en">Life Sciences</a></div> </div> </div> Mon, 03 Jul 2017 09:07:36 +0000 gregladen 34444 at Comments of the Week #166: from expanding faster than light to periodic mass extinctions <span>Comments of the Week #166: from expanding faster than light to periodic mass extinctions</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><blockquote><p>“Already in my original paper I stressed the circumstance that I was unable to give a logical reason for the exclusion principle or to deduce it from more general assumptions. I had always the feeling, and I still have it today, that this is a deficiency.” -Wolfgang Pauli</p></blockquote> <p>There's never a shortage of scientific topics to explore and take interest in here at <a href="">Starts With A Bang!</a> While we have our usual slew of articles, controversies, opinions and more this week, I'm also so pleased to share <a href="">a new podcast</a> with you! This month, thanks to our <a href="" target="_blank" rel="noopener noreferrer">Patreon supporters</a>, we took on a very bold topic, the one of our very existence. Believe it or not, there's one quantum rule that makes it all possible, and that's <a href="">the Pauli exclusion principle</a>!</p> <p></p><center> <iframe src=";auto_play=false&amp;hide_related=false&amp;show_comments=true&amp;show_user=true&amp;show_reposts=false&amp;visual=true" width="100%" height="450" frameborder="no" scrolling="no"></iframe><p></p></center>So have a listen to 20 minutes of incredible science goodness, and then take a look back at everything we've covered this past week, including: <ul><li><a href="" target="_blank" rel="noopener noreferrer">Can the Universe ever expand faster than the speed of light?</a> (for Ask Ethan),</li> <li><a href="" target="_blank" rel="noopener noreferrer">Three spectacular nebulae caught together, revealing stunning details about star birth</a> (for Mostly Mute Monday),</li> <li><a href="" target="_blank" rel="noopener noreferrer">From wartime devastation to academic discrimination, Cecile DeWitt-Morette overcame it all</a> (a retrospective by Paul Halpern),</li> <li><a href="" target="_blank" rel="noopener noreferrer">Goodbye, Planet Nine! New and better data disfavors a giant world beyond Neptune</a>,</li> <li><a href="" target="_blank" rel="noopener noreferrer">LIGO's successor approved; will discover incredible new sources of gravitational waves</a>, and</li> <li><a href="" target="_blank" rel="noopener noreferrer">Are mass exinctions periodic, and are we due for one?</a></li> </ul><p>With everything we've covered, you've had plenty to say, and I want to address as much of it as possible! Come join us for this edition of our <a href="">comments of the week</a>!</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/06/BlackHoleArtZoomOut.medium.jpg"><img class="size-medium wp-image-36221" src="/files/startswithabang/files/2017/06/BlackHoleArtZoomOut.medium-600x223.jpg" alt="Although we've seen black holes directly merging three separate times in the Universe, we know many more exist. Here's where they must be. Image credit: LIGO/Caltech/MIT/Sonoma State (Aurore Simonnet)." width="600" height="223" /></a> Although we've seen black holes directly merging three separate times in the Universe, we know many more exist. Here's where they must be. Image credit: LIGO/Caltech/MIT/Sonoma State (Aurore Simonnet). </div> <p>From <a href="">Paul Dekous</a> on criticism of LIGO: "To my knowledge it is the first ‘official’ criticism so it’s not like they have to use their time to fight of any other criticism, at least they could have said; “sure, now is a bad time, but you’ll get a response in a month or two”."</p></blockquote> <p>There are a lot of reasons to be skeptical of what someone is doing, but it's vital to not be overly skeptical. This is not the same situation as faster-than-light neutrinos, as the BICEP2 results, or even as WMAP claiming insanely early reionization. If the Danish group is right, it means that the LIGO detections are still there, and still robust, but at a lower significance. It also means that there is a component to the LIGO noise that they haven't correctly accounted for, and that might be problematic.</p> <p>That's best-case-scenario for the Danish group. The other major (and favored) scenario is that it is the Danes that are wrong. This has courted enough controversy that this time I will likely write a piece myself this week on LIGO, its criticism, and what it all means.</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/03/Htautau1-1200x675.jpg"><img class="size-medium wp-image-35938" src="/files/startswithabang/files/2017/03/Htautau1-1200x675-600x338.jpg" alt="A Higgs boson event as seen in the Compact Muon Solenoid detector at the Large Hadron Collider. This one high-energy collision illustrates the power of energy conversion, which always exists in the form of particles. Image credit: CERN / CMS Collaboration." width="600" height="338" /></a> A Higgs boson event as seen in the Compact Muon Solenoid detector at the Large Hadron Collider. This one high-energy collision illustrates the power of energy conversion, which always exists in the form of particles. Image credit: CERN / CMS Collaboration. </div> <p>From <a href="">Elle H.C.</a> on a strange phenomenon from CERN: "Well I was always curious if collisions at the LHC could cause tiny vibrations in SpaceTime and shake up surrounding matter with the risk of disrupting protons, like how you can shake and break a glass from a distance, with a speaker with a strong enough amplitude."</p></blockquote> <p>I have never heard of this theory. How would it work within the Standard Model and/or General Relativity? I, myself, am not aware of any physically consistent scenario that has this sort of consequence arising from the LHC. I brought up Hitchens' razor this week -- what can be asserted without evidence can be dismissed without evidence -- and I am curious whether that applies here?</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/06/Single_dish.jpg"><img class="size-medium wp-image-36263" src="/files/startswithabang/files/2017/06/Single_dish-600x560.jpg" alt="" width="600" height="560" /></a> A single dish that's currently part of the MeerKAT array will be incorporated into the Square Kilometer Array, along with around 4,000 other equivalent dishes. Image credit: SKA Africa Technical Newsletter, 1 (2016). </div> <p>From <a href="">Frank</a> on how telescopes create images: "I never understood how radio telescopes create images."</p></blockquote> <p>How is a radio telescope different from any other telescope? When a signal arrives, you only need to deduce just a few pieces of information about that signal:</p> <ul><li>How much energy was in the signal,</li> <li>What the measured frequency of that signal was,</li> <li>And where on the sky that signal was located.</li> </ul><p>That's it. The first one can tell you the "apparent brightness," the second tells you a combination of the rest-frame frequency and the cosmic redshift, and the third one tells you angular position. So point your telescopes, they reflect and focus the waves to a point, and we assign a color/magnitude to that particular position dependent on how we choose to visualize/represent the radio signals.</p> <p>It's really no different than how we "color the Universe" in any other light. I strongly recommend, in that vein, if you want to learn more in general, that you read the book <a href="">Coloring The Universe by Arcand, Watzke and Rector</a>, which I <a href="">reviewed in a bit of depth</a> around a year ago here.</p> <div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/06/Island_of_Stability_derived_from_Zagrebaev.png"><img class="size-medium wp-image-36282" src="/files/startswithabang/files/2017/06/Island_of_Stability_derived_from_Zagrebaev-600x272.png" alt="" width="600" height="272" /></a> The theoretical 'island of stability' (circled) in nuclear physics. </div> <blockquote><p>From <a href="">eric</a> on the nuclear physics phenomenon of the island of stability: "A word of caution for the layfolk: “stability” is a relative term. It’s entirely possible that the nuclear shell effects Ethan talks about increases the stability of the isotopes in the ‘island of stability’ by a factor of 1,000 or even 1,000,000. But that may mean increasing their expected half-lives from nanoseconds to milliseconds. AFAIK nobody int the business expects these elements to be truly stable or even stable enough to allow us to build up macroscopic supplies of them as we do the actinides. But hey, we won’t know for sure unless/until we produce them."</p></blockquote> <p>This is a really good point. When we talk about nuclear physics, we're dealing with tremendously complicated systems where the strong nuclear force and electromagnetic force -- and even the weak force -- are all at play in extremely large composite systems. A single proton has three valence quarks; these nuclei in question have over 250 nucleons each, with around 800 valence quarks alone, all in a single quantum system. We can predict that these various isotopes of particular nuclei will be <em>more stable</em> than the ones surrounding them on the periodic table, but exactly how much needs to be determined experimentally.</p> <p>And that is still, apparently, quite a ways away.</p> <div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/06/redshifts.gif"><img class="size-medium wp-image-36278" src="/files/startswithabang/files/2017/06/redshifts-600x548.gif" alt="" width="600" height="548" /></a> The farther a galaxy is, the faster it expands away from us, and the more its light gets redshifted, necessitating that we look at longer and longer wavelengths. Beyond a certain distance, galaxies become unreachable by anything we emit today, even at the speed of light. Image credit: Larry McNish, RASC Calgary. </div> <blockquote><p>From <a href="">Frank Bennett</a> on whether the Universe can expand faster than light: "I think you need to show, as you have in other articles, that the effect is a purely geometric consequence of the expansion."</p></blockquote> <p>It's quite difficult to show that for a single object. When you measure the light from, say, a distant galaxy, you can measure the same things I talked about when the other Frank asked about how radio telescopes create images, including the wavelength and distribution of light from that object. Some of that redshift will be due to the stretching of spacetime; some of that redshift will be due to "peculiar velocity," or the motion of the object itself relative to its local frame-of-reference.</p> <p>The only way to know how much is one type versus the other is to measure a large variety of objects at a variety of distances; you'll wind up with a picture of the overall expansion of the Universe and another picture, superimposed atop it, of the local effects of gravity pushing and pushing individual galaxies at speeds of tens, hundreds or even thousands of km/s relative to the overall Hubble flow. But on large scales, that geometric effect is easily seen, and extraordinarily prominent.</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2016/12/FERMIphoton_race_full.jpg"><img class="size-medium wp-image-35541" src="/files/startswithabang/files/2016/12/FERMIphoton_race_full-600x405.jpg" alt="" width="600" height="405" /></a> In this illustration, one photon (purple) carries a million times the energy of another (yellow). Fermi data on two photons from a gamma-ray burst fail to show any travel delay, showing the speed of light's constancy across energy. Image credit: NASA/Sonoma State University/Aurore Simonnet. </div> <p>From <a href="">Pentacho Valev</a> on what the constancy of the speed of light means: "Any correct interpretation of the Doppler effect implies that the speed of light varies with the speed of the observer."</p></blockquote> <p>Not quite, and I have read many of your comments to attempt to see where I think you're making a mistake. You're saying, basically, that:</p> <ul><li>You measure a frequency for your light.</li> <li>Frequency is the speed at which the pulses move divided by the distance between the pulses.</li> <li>A moving observer sees a different frequency than a stationary observer.</li> </ul><p>And therefore, you conclude, that the speed at which the pulses move must be different for different observers, and hence the speed of light is constant. That's what I <em>think</em> your reasoning is.</p> <p>But what Einstein's theory says is that the speed at which the pulses move is <strong>always the speed of light in a vacuum for any type of light or any observer</strong>. So what's changing, for different observers, is twofold: the distance between the pulses, which you have right, by the fact of length contraction, but also the way that each observer measures time, due to the effect of time dilation, which is not encoded anywhere in your plain-English descriptions but which matters nonetheless. That is how the speed of light remains constant for all observers.</p> <p>Read this a few times and think about it for a while, and see if you don't rethink how you've conceived of this problem.</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/06/2cf52b2594e613239ce3c9f851943073.jpg"><img class="size-medium wp-image-36290" src="/files/startswithabang/files/2017/06/2cf52b2594e613239ce3c9f851943073-600x414.jpg" alt="Cecile DeWitt-Morette at her desk in her office in R.L. Moore Hall. Image credit: University of Texas at Austin, News and Information Service / L. Murphy." width="600" height="414" /></a> Cecile DeWitt-Morette at her desk in her office in R.L. Moore Hall. Image credit: University of Texas at Austin, News and Information Service / L. Murphy. </div> <p>A classic Ethan vs. Denier moment <a href="">as related by Denier</a> this past week on the topic of Cecile DeWitt-Morette: "<em>Ethan</em>: When you have rules that treat men and women equally in theory, but the practical application of the rules leads to unequal <b>results</b>, that’s a classic example of a rule that doesn’t work.<br /><em>Denier</em>: No Ethan. Bad!<br /> When the practical application of rules leads to unequal <b>opportunity</b>, that’s a classic example of a rule that doesn’t work. The insistence of equality of outcome is a nightmarishly illiberal idea."</p></blockquote> <p>So there's <a href="">a lot more to Denier's comment(s)</a> that you're welcome to read, but the crux of this is very difficult, because I don't inherently disagree with the premise here. Unequal opportunity is bad; if everyone has equal opportunity and we see unequal results, that's not inherently bad. In fact, that would be, ideally, what a true meritocracy would look like.</p> <p>The problem arises when we get into the practical applications. How do you measure whether the opportunity is equal or unequal? Is that something that's even possible? The original rules of UNC appeared to be equal, right? That if one spouse was faculty, then anti-nepotism rules just prohibited the other one from becoming faculty. But practically, most qualified male/female couples had the male member be older and more career-advanced when hired, which effectively barred the female member from access to a full professorship. You will notice that <a href="">UNC's rules <em>and goals </em>are very, very different now</a>.</p> <p>The best argument I ever read about this issue <a href="">was written by David Souter</a>, when he spoke at Harvard in 2010 on the topic of Plessy vs. Ferguson. It's incredibly nuanced, talking about the different questions one was asking about the topics of what equal/unequal opportunity means: does it mean equal facilities, equal access, equal results, etc.? And while the answer to the question of race and segregation and barring access is a no-brainer today, he does a good job of getting into the heads of judges circa the late 19th century. So you can argue about opportunity vs. results, but when you see unequal results, boy, does it strongly suggest the presence of unequal opportunity.</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/06/18558574_10154321265940194_4293925206857578202_o.jpg"><img class="size-medium wp-image-36292" src="/files/startswithabang/files/2017/06/18558574_10154321265940194_4293925206857578202_o-600x393.jpg" alt="" width="600" height="393" /></a> Cécile DeWitt-Morette (on ladder) and colleagues, circa 1973, give a temporary observatory that will be used in Mauritania a dry run in a UT campus parking lot. Image credit: University of Texas at Austin. </div> <p>From <a href="">Elle H.C.</a> on what Cecile DeWitt-Morette actually faced: "Some comments here are distasteful, and all this because she dared to speak up about some inequality along the way.<br /> What do you want, that she just had kept it quiet and only talked about how good life has been to her?"</p></blockquote> <p>You can read <a href="">an entire history of the event</a> in an interview that the American Institute of Physics did with Bryce and Cecile when both were still alive. You are, of course, free to think whatever you like about it, but this is what they have to say in their own words. Here are some relevant parts:</p> <blockquote><p>Bryce: "But in the meantime, the people at Chapel Hill has persuaded me to consider putting this thing in Chapel Hill. And I was assured by the department there that it would be bona fide and it wouldn't be run by Bahnson. Chapel Hill is a beautiful place, and I was wanting to get out of Livermore for an academic position, so we went there, both of us, as visiting research professors. After a few years I was given a regular professorship and Cecile was demoted to a lecturer."</p> <p>Cecile: "Without being told it was a demotion. "Oh, it will be so much better for you." And that's the part I didn't like, the hypocrisy of letting me believe that it was better. And in the French context, it could have been better, so I took it for granted."</p></blockquote> <p>Cecile was, no doubt, an opportunist, like a great many other people. And she demanded good things for herself, like many others. Should she just have settled for whatever was offered to her? I would again point to the changes in <a href="">how spousal hiring is done at UNC</a> and across academia as evidence that her decisions helped affect some tremendous positive change.</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/06/Earth_and_Super-Earth.jpg"><img class="size-medium wp-image-36294" src="/files/startswithabang/files/2017/06/Earth_and_Super-Earth-600x360.jpg" alt="" width="600" height="360" /></a> In theory, Planet Nine would likely be similar to the exoplanet 55 Cancri e, which is approximately twice the Earth's radius, but eight times the Earth's mass. This new study, however, disfavors the existence of such a world in our outer Solar System entirely. Image credit: NASA/JPL-Caltech/R. Hurt (SSC). </div> <p>From <a href="">John</a> on the demise of the evidence for Planet Nine: "The falsifiability of the Planet Nine theory made it Science. The observations made it unlikely. Sic transit gloria mundi novem."</p></blockquote> <p>I liked Planet Nine as an idea, even though I was skeptical. There are other, indirect pieces of evidence that have come out against Planet Nine, largely based on the observations of TNOs in the outer solar system, but I thought it was most important to highlight the fact that Batygin and Brown's original dataset that motivated it in the first place is now looking... shall we say, woefully insufficient.</p> <p>Also, I can never see "sic transit gloria" without thinking about Max Fischer anymore.</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/06/Artist_s_impression_of_the_three_LISA_spacecraft.jpg"><img class="size-medium wp-image-36300" src="/files/startswithabang/files/2017/06/Artist_s_impression_of_the_three_LISA_spacecraft-600x392.jpg" alt="An artist's impression of the three LISA spacecraft shows that the ripples in space generated by longer-period gravitational wave sources should provide an interesting new window on the Universe. Image credit: EADS Astrium." width="600" height="392" /></a> An artist's impression of the three LISA spacecraft shows that the ripples in space generated by longer-period gravitational wave sources should provide an interesting new window on the Universe. Image credit: EADS Astrium. </div> <p>From <a href="">Steve Blackband</a> on LIGO, LISA and noise: "How is this affected, if at all, by your recent post that casts doubts on the LIGO observations and suggests that all they saw was noise?"</p></blockquote> <p>First off, no one (serious) is suggesting that "all LIGO saw was noise" at all. People are suggesting that LIGO is seeing correlations in noise that shouldn't be there, and that may pose an issue for the robustness and reliability of the signals, which still show up even with that correlated noise.</p> <p>But what's awesome about LISA is that the overwhelming majority of sources-of-noise that LIGO must contend with disappear for LISA. LISA will have the vacuum of space to contend with, rather than the best vacuum we can make inside a long chamber here on Earth. LISA will be in orbit around Earth, and will lose all the sources of noise from the Earth's ground. Thermal noise will be at a minimum due to active and/or passive cooling on the spacecraft. (I'm not sure that's been finalized.)</p> <p>One of the best parts of LISA, that I tried hard to emphasize, is how <em>non</em>-noisy it will be compared to LIGO. And if there is this mysterious noise correlation, that will be incredibly interesting, and perhaps will lead to -- if not new physics -- at least new advances in understanding the sources of a new type of interferometer noise.</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2016/08/1-U1TKSOmpfiu_JRkSDzPquA.jpeg"><img class="size-medium wp-image-34964" src="/files/startswithabang/files/2016/08/1-U1TKSOmpfiu_JRkSDzPquA-600x440.jpeg" alt="" width="600" height="440" /></a> Special relativity (dotted) and general relativity (solid) predictions for distances in the expanding Universe. Definitively, only GR’s predictions match what we observe. Image credit: Wikimedia Commons user Redshiftimprove. </div> <p>From <a href="">Sinisa Lazarek</a> on dealing with relativity/Einstein deniers: "And then at the end of the day, when scientists call you cranks, you feel in your arrogance/ignorance that there is some conspiracy that no one is allowed to question GR/SR, when it’s not the case. There are hundreds of valid scientific papers out there with valid arguments on how to build/change something beyond GR. Questioning GR doesn’t make you cranks… HOW YOU question GR makes you cranks."</p></blockquote> <p>What do you do when you're presented with something that doesn't make sense to you? You think about it, you listen to it, and yet it just defies common sense. You know, in your gut, that it can't be right. What do you do?</p> <p>We all get that knee-jerk reaction, the one that says, "that's gotta be wrong!" I had it yesterday; a friend of mine was telling me about kissing bugs, and that they bite your lips and put something into your blood that just lays there, dormant, for a decade or more, and then you develop symptoms and die. And I had that reaction, and said that it sounded like those made-up animals that Australians tell tourists about to trick them, like 'drop bears' and 'circle snakes.' (And yes, I know 'rock melons' are real; thanks Australia.) But what did I do? Did I just talk about how that can't be right, and tell what I knew to argue the point? Or did I look it up, and learn that kissing bugs are a common name for the insect that transmits the protist that causes Chagas' Disease?</p> <p>My point is that it's easy to rely on common-sense and decry something that runs counter to that as an obvious falsehood. But life isn't obvious, and in particular, science isn't obvious. In fact, the fact that science isn't obvious is why it's so hard, why it takes so much training, and why the knowledge it takes to engage in it is so specialized. If it were obvious, we wouldn't need to be scientists to make the advances we've made. Think about this the next time someone advocates "common sense" solutions to our problems. Do you want common sense? Or do you want hard work, science, and evidence? Think about it, because if you're willing to put in the hard work, you can learn it all for yourself.</p> <blockquote><div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/06/Planetoid_crashing_into_primordial_Earth-1200x908.jpg"><img class="size-medium wp-image-36304" src="/files/startswithabang/files/2017/06/Planetoid_crashing_into_primordial_Earth-1200x908-600x454.jpg" alt="A large, rapidly moving mass that strikes the Earth would be certainly capable of causing a mass extinction event. However, such a theory would require strong evidence of periodic impacts, which Earth doesn't seem to have. Image credit: Don Davis / NASA." width="600" height="454" /></a> A large, rapidly moving mass that strikes the Earth would be certainly capable of causing a mass extinction event. However, such a theory would require strong evidence of periodic impacts, which Earth doesn't seem to have. Image credit: Don Davis / NASA. </div> <p>From <a href="">Denier</a> on my opinion about our ability to introspect: "Were the last few words just a throw-away bit with truthiness feel used only to provide punctuation to the end of your piece? Or is there an epistemological school you are drawing from for that statement? Do you think that as a species we don’t do collective introspection well?"</p></blockquote> <p>What I said, in particular that led to this question was: <strong>For the foreseeable future, the Earth isn’t at increased risk of a natural disaster coming from the Universe. Instead, <b>it looks like our greatest danger is posed by the one place we all dread to look: at ourselves</b>.</strong></p> <p>It isn't about introspection that I was getting at, but rather the <a href="">well-documented</a> <a href="">fact</a> that humans are quite bad at evaluating risks. In particular, we're very bad at evaluating low-probability high-consequence risks, and almost always overstate those in our minds, compared to higher-probability risks. The idea of a catastrophic impact -- the focus of my entire piece -- is one such example of a low-probability high-consequence event, and it's one that humanity really frets about. The idea that the LHC would create a black hole and then that the black hole would destroy the Earth was another. And yet, actual problems like the deadliness of mosquito-borne diseases or simply the flu are just brushed off.</p> <p>It is our ability to fret about phantom problems and exceedingly unlikely scenarios while failing to mitigate actual, ongoing, tangible dilemmas that frustrate me.</p> <div style="width: 610px;display:block;margin:0 auto;"><a href="/files/startswithabang/files/2017/06/Brown-Dwarfs.jpg"><img class="size-medium wp-image-36307" src="/files/startswithabang/files/2017/06/Brown-Dwarfs-600x601.jpg" alt="" width="600" height="601" /></a> These are the two brown dwarfs that make up Luhman 16, and they may eventually merge together to create a star. Image credit: NASA/JPL/Gemini Observatory/AURA/NSF. </div> <blockquote><p>And finally, from <a href="">Jose Pacheco</a> on brown dwarfs: "One thing’s for sure, Brown Dwarf. You’ll never be bright enough to make Dad Star proud."</p></blockquote> <p>But this isn't because of a failing on either the brown dwarf's part or of another star that ever existed in the Universe; it's because all the other stars -- parent stars, sibling stars, etc. -- likely will no longer exist by time the brown dwarf merges with another to become a true star. The rate of decay is slow; gravitational radiation carries away mere Watts of energy for this brown dwarf system. But give it enough time, like all the time the Universe has left, and eventually this orbital decay will make a star. No matter how long-gone your progenitors are, you still shine bright, all the same.</p> </div> <span><a title="View user profile." href="/author/esiegel">esiegel</a></span> <span>Sun, 06/25/2017 - 09:11</span> <div class="field field--name-field-blog-categories field--type-entity-reference field--label-inline"> <div class="field--label">Categories</div> <div class="field--items"> <div class="field--item"><a href="/channel/life-sciences" hreflang="en">Life Sciences</a></div> </div> </div> Sun, 25 Jun 2017 13:11:29 +0000 esiegel 37016 at Odd Ancient South African Human "Ancestor" Is Young <span>Odd Ancient South African Human &quot;Ancestor&quot; Is Young</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><p>You've heard of <em>Homo naledi</em>, the strange "human ancestor" (really, a cousin) found a while back in South Africa. There were many skeletal remains in a cave, in the kind of shape you'd expect if they had crawled into the cave and died there, not much disturbed. They look enough like other members of our genus, <em>Homo</em>, to be called <em>Homo</em>, but if we assume that increase in brain size is the hallmark of our species, they seem to be an early grade.</p> <p>Over the last ten years, we have come to appreciate the fact that our genus may have differentiated into multiple species that did not have a large brain after all, and <em>Homo naledi</em> is one of the reasons we think that. And, just as the "Hobbit" of Indonesia (flores) has recently been re-dated to be a bit older than people thought, <em>Homo naledi</em> is now dated to be a bit later than people may have thought.</p> <div style="width: 620px;display:block;margin:0 auto;"><a href="/files/gregladen/files/2017/05/Lesedi_08.jpg"><img src="" alt="Schematic of the Rising Star cave system. Picture: Marina Elliott/Wits University" width="610" height="385" class="size-large wp-image-24059" /></a> Schematic of the Rising Star cave system. Picture: Marina Elliott/Wits University </div> <p>For me, this is an "I told you so" moment. First, I understand, as do most of my colleagues (but not all), that a regular change over time in a trait in one lineage does not magically cause a parallel change in another lineage (though the co-evolution of a single trait in a similar direction along parallel lineages is certainly possible.) So, there was no reason to require that all later period hominins be like all other later period hominins in those later-emerging traits. Also, since no one has ever adequately explained what the heck our big brains are for, I don't subscribe to the presumption that all evolution will always evolve the big brain just because our own big brains insist that they are really cool. So, a late small brained hominin in our genus but existing long after the split with us is actually somewhat expected. </p> <p>Then, there is my sense of age based on the things I've seen in the area's caves.</p> <div style="width: 310px;float:right;"><a href="/files/gregladen/files/2017/05/Screen-Shot-2017-05-09-at-10.45.29-AM.png"><img src="" alt="Geologist Dr Hannah Hilbert-Wolf studying difficult to reach flowstones in a small side passage in the Dinaledi Chamber. Picture: Wits University" width="300" height="430" class="size-medium wp-image-24060" /></a> Geologist Dr Hannah Hilbert-Wolf studying difficult to reach flowstones in a small side passage in the Dinaledi Chamber. Picture: Wits University </div> <p>Some time ago, Lee Berger took me around some of the cave he had poking around in (long before this hominin was discovered) and showed me several animals that had crawled into the caves, probably looking for water during an arid period (this is already a fairly dry area). They had died in place and become mummified. In other caves, I've seen similar things, like a troop of baboons that somehow got into a cave with no known entrance and died, as well as bats that died in situ and mummified against the rock they died on. </p> <p>On another occasion, Ron Clarke, another anthropologist working in the area, showed me the famous "Little Foot" which is a fossil that represents that mummy-to-stone transition, while mostly sitting on the surface of the floor(ish) of a very deep and inaccessible cave. Meanwhile, I'd been working with my friend and colleague Francis Thackeray, and he demonstrated to me how many of the diverse bits and pieces we find of australopithecines are actually probably part of individual skeletons, but discovered and excavated at very different times. These are creatures that got in the cave somehow, and were only somewhat disarticulated after death. </p> <p>The whole "crawled into the cave" mode of entering the fossil record, and its presumed variant, "fell to one's death in the cave" is different from the previously presumed process of "leopard kills you, drags you onto a tree branch hanging over a cave entrance and your bones fall into the cave" means of becoming a fossil. It is of course possible, even likely, that both of these processes occurred at various times and places. </p> <p><em>Homo naledi</em>, according to Lee Berger, may represent a third way of getting into one of these famous caves. He suggests that the hominins themselves dragged the dead bodies of each other into the caves, as a form of treatment of the dead. That is a spectacularly controversial claim, of course, since with a small brain how can you have a god, and without a god, how can you have ritual or burial? Of course, elephants treat their dead specially sometimes, and their brain is right where it is supposed to be on the famous mouse-to-elephant curve of brain size. And, I'd bet a dozen donuts that even though <em>Homo naledi</em> has a small brain compared to, say, yours or mine, it is probably a good measure above that comparative curve. It was a primate, after all.</p> <div style="width: 310px;float:left;"><a href="/files/gregladen/files/2017/05/Screen-Shot-2017-05-09-at-10.46.25-AM.png"><img src="" alt="left to right: Marina Elliott, Maropeng Ramalepa and Mpume Hlophe. Picture: Wits University/Wayne Crichton" width="300" height="236" class="size-medium wp-image-24061" /></a> left to right: Marina Elliott, Maropeng Ramalepa and Mpume Hlophe. Picture: Wits University/Wayne Crichton </div> <p>But I digress in several directions, lets get to the point. The site of Rising Star Cave, South Africa, where <em>Homo naledi</em> was discovered, is now dated. These things are always subject to revision and updating, but for now, it seems like we have a pretty good estimate of the age of this incredible site.</p> <p>The site dates to some time between about 414,000 years ago and 236,000 years ago. That means that the site overlaps with the approximate age of the earliest, probably, modern humans. Here are the details from the abstract of the<a href=""> paper, published this morning</a>:</p> <blockquote><p>New ages for flowstone, sediments and fossil bones from the Dinaledi Chamber are presented. We combined optically stimulated luminescence dating of sediments with U-Th and palaeomagnetic analyses of flowstones to establish that all sediments containing Homo naledi fossils can be allocated to a single stratigraphic entity (sub-unit 3b), interpreted to be deposited between 236 ka and 414 ka. This result has been confirmed independently by dating three H. naledi teeth with combined U-series and electron spin resonance (US-ESR) dating. Two dating scenarios for the fossils were tested by varying the assumed levels of 222Rn loss in the encasing sediments: a maximum age scenario provides an average age for the two least altered fossil teeth of 253 +82/–70 ka, whilst a minimum age scenario yields an average age of 200 +70/–61 ka. We consider the maximum age scenario to more closely reflect conditions in the cave, and therefore, the true age of the fossils. By combining the US-ESR maximum age estimate obtained from the teeth, with the U-Th age for the oldest flowstone overlying Homo naledi fossils, we have constrained the depositional age of Homo naledi to a period between 236 ka and 335 ka. These age results demonstrate that a morphologically primitive hominin, Homo naledi, survived into the later parts of the Pleistocene in Africa, and indicate a much younger age for the Homo naledi fossils than have previously been hypothesized based on their morphology.</p></blockquote> <div style="width: 310px;float:right;"><a href="/files/gregladen/files/2017/05/Screen-Shot-2017-05-09-at-10.49.47-AM.png"><img src="" alt="&quot;Neo&quot; skull of Homo naledi from the Lesedi Chamber. Photo credit: Wits University/John Hawks" width="300" height="388" class="size-medium wp-image-24063" /></a> "Neo" skull of Homo naledi from the Lesedi Chamber. Photo credit: Wits University/John Hawks </div> <p>In addition to this date, it is reported that there are more fossil remains, from another cave called Lesedi Chamber. <a href="">Here is the paper</a> for that, which reports "... Further exploration led to the discovery of hominin material, now comprising 131 hominin specimens, within a second chamber, the Lesedi Chamber. The Lesedi Chamber is far separated from the Dinaledi Chamber within the Rising Star cave system, and represents a second depositional context for hominin remains. In each of three collection areas within the Lesedi Chamber, diagnostic skeletal material allows a clear attribution to <em>H. naledi</em>. Both adult and immature material is present. The hominin remains represent at least three individuals based upon duplication of elements, but more individuals are likely present based upon the spatial context. The most significant specimen is the near-complete cranium of a large individual, designated LES1, with an endocranial volume of approximately 610 ml and associated postcranial remains. The Lesedi Chamber skeletal sample extends our knowledge of the morphology and variation of <em>H. naledi</em>, and evidence of <em>H. naledi</em> from both recovery localities shows a consistent pattern of differentiation from other hominin species."</p> <p>Since both articles are OpenAccess, you can see them for yourself. Kudos to the authors for publishing in an OpenAccess journal.</p> <p>And now, back to my original digression. One gets a sense of how landscapes and land forms develop, and while this can be misleading, it is not entirely absurd to postulate rough comparative ages for things you can see based on other things you've seen. I had assumed from the way they were described originally that the Rising Star hominins would not be millions of years old. Even though Bigfoot (found by Clarke) was millions of years old and essentially on the surface (of a deeply buried unfilled chamber) I guessed that over a million-year time scale, the Rising Star material would either become diagenetically inviable as fossils or buried in sediment, or both. But over hundreds of thousands of years? That was plausible to me. In fact, I figured the remains to possibly have been even younger, and if a date half the age as suggested was calculated, I would not have been surprised. </p> <p>The evolution of our thinking about human evolution went through a period when we threw out all of our old conceptions about a gradual ape to human process, replacing that with a linear evolutionary pattern with things happening in what was then a surprising order, with many human traits emerging one at a time long before brains got big. There was some diversity observed then, but the next phase of our thinking involved understanding a dramatic diverstiy of pre <em>Homo</em> (the genus) life forms followed by the essential erasure of variation with the rise of <em>Homo erectus </em>and the like. Over the last decade and a half, we are now realizing that while the later members of our genus probably did cause, or at least, were associated with, a general decrease in that early diversity, later diversity arose anyway, and there were more different kinds of hominids, very different in some cases, late into our history. Word on the street is that we can expect to learn about even more diversity in coming years.</p> <p>_______________________________________________________________________<br /> Paul HGM Dirks, Eric M Roberts, Hannah Hilbert-Wolf, Jan D Kramers, John Hawks, Anthony Dosseto, Mathieu Duval, Marina Elliott, Mary Evans, Rainer Grün, John Hellstrom, Andy IR Herries, Renaud Joannes-Boyau, Tebogo V Makhubela, Christa J Placzek, Jessie Robbins, Carl Spandler, Jelle Wiersma, Jon Woodhead, Lee R Berger. 2017. The age of Homo naledi and associated sediments in the Rising Star Cave, South Africa. May 2017. <a href="">eLife</a>. </p> <p>Related books:</p> <p><a target="_blank" href=";camp=1789&amp;creative=9325&amp;creativeASIN=1426218117&amp;linkCode=as2&amp;tag=grlasbl0a-20&amp;linkId=fc6e4d3e3b9a24626553346ace614402">Almost Human: The Astonishing Tale of Homo naledi and the Discovery That Changed Our Human Story</a><img src="//;l=am2&amp;o=1&amp;a=1426218117" width="1" height="1" border="0" alt="" style="border:none !important; margin:0px !important;" /></p> <p><a target="_blank" href=";camp=1789&amp;creative=9325&amp;creativeASIN=1770070656&amp;linkCode=as2&amp;tag=grlasbl0a-20&amp;linkId=857e83a67b535e598d4de60b6900882e">Field Guide to the Cradle of Humankind: Sterkfontein, Swartkrans, Kromdraai &amp; Environs World Heritage Site</a><img src="//;l=am2&amp;o=1&amp;a=1770070656" width="1" height="1" border="0" alt="" style="border:none !important; margin:0px !important;" /></p> <p><a target="_blank" href=";camp=1789&amp;creative=9325&amp;creativeASIN=0471568376&amp;linkCode=as2&amp;tag=grlasbl0a-20&amp;linkId=e1083d0166bb03fd91c0506f7247857d">From Apes to Angels: Essays in Anthropology in Honor of Phillip V. Tobias</a><img src="//;l=am2&amp;o=1&amp;a=0471568376" width="1" height="1" border="0" alt="" style="border:none !important; margin:0px !important;" /></p> </div> <span><a title="View user profile." href="/author/gregladen">gregladen</a></span> <span>Tue, 05/09/2017 - 05:07</span> <div class="field field--name-field-blog-categories field--type-entity-reference field--label-inline"> <div class="field--label">Categories</div> <div class="field--items"> <div class="field--item"><a href="/channel/life-sciences" hreflang="en">Life Sciences</a></div> </div> </div> Tue, 09 May 2017 09:07:48 +0000 gregladen 34383 at Why I ate a Pangolin <span>Why I ate a Pangolin</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><p>The Lese people practice swidden horticulture in the Ituri Forest, Congo (formerly Zaire). Living in the same area are the Efe people, sometimes known as Pygmies (but that may be an inappropriate term). The Efe and Lese share a culture, in a sense, but are distinct entities within that culture, as distinct as any people living integrated by side by side ever are. The Efe are hunter-gatherers, but the gathering of wild food part of that is largely supplanted by a traditional system of tacit exchange between Efe women and Lese farmers, whereby the Efe provide labor and the farmers provide food. The Efe men also work on the farms sometimes, but their contribution to the family’s diet is more typically from foraged goods, including plants but mostly animals, and during a particular season of the year, the products of honey bee nests. </p> <p>For several years, in the 1980s and early 90s, I lived in Zaire (now Congo) for several months out of each year (generally between May and January, roughly), and for much of that time I was in the Ituri with the Lese and Efe. During that time, I spent much of the time in the forest with the Efe (very few of the researches on that long term multidisciplinary project did that -- most spent their time with the Lese for various reasons). </p> <p>To go from our study site to the grocery store (which was not really a grocery store because they did not exist in that part of Zaire, but a city with markets) was about a week’s trip or more. Only a few days of that was driving, the rest fixing the broken truck, doing the shopping, etc. So, one did this infrequently. There was no local market during my time there, though one opened up 10 clicks away for a while, at which one might or might not be able to buy a chicken or a yam, if you showed up early.</p> <p>I (and this pertains to most of my colleagues as well, only a few of us would be at the site at a time) would buy sacks of rice and beans and other long term food items in the city, and carefully curate them at the base camp, a small village constructed of wattle and daub leaf-roofed huts and outhouses. When I went to the forest just to live with or observe the Efe, I would bring the exact amount of food I would need to survive if all I did was feed myself. This way my presence would not affect the Efe’s food budget. But, this is a sharing culture and it would have been very bad for me to just eat that food. I feely shared my food with my fellow camp members, and they shared their food, and my food was almost exactly the same as their local food (rice was grown there) except I would have beans and they are not local. Otherwise, the same. </p> <p>This meant that I ate what they ate. </p> <p>Other times, I would hire Efe and maybe one Lese to go with me to the forest to carry out research. I’d be careful to hire them for limited amounts of time to not disrupt their lives too much, but there was very little difference between them working for me and, say, getting honey during honey season. I would only ask them to work with me for a few hours a day and they would otherwise forage. On these trips, I brought more food, for them, because our geographic location and the work we were doing interfered with their normal food getting activities, so I made up for that. But still, during these times we ate plenty of forest foods.</p> <p>So, what do the Efe (and their Lese compatriot) eat?</p> <p>Locally, the plant diet is insufficient nutritionally, and often, children are undernourished. There is a hunger season during which the plants from the forest and gardens are rare or absent at the same time, and this is often the death season. No one dies form starving, really (though that apparently can happen) but they have another dangerous disease, and the lack of food may put an ill individual over the top. During one bad hungers season, a small family attempted mass suicide, and mostly succeeded. </p> <p>Locally, there is no beef, or as is the case a couple of hundred clicks away in most directions, commercially harvested fish. They have goats but the are ceremonial and seem to be never eaten. The Lese have chickens, a few, and they are eaten now and then. The wild animal foods they eat are incredibly important. Without that, they would be in very bad shape. </p> <p>The most common animals they eat, as in day to day and mundane, are a form of antelope called the Blue Duiker, and monkeys, usually Mangabeys. During a certain season they eat a fair umber of another animal, like but not exactly a duiker, called a water Cheverotain. But since food supply is so unpredictable, they are always on the lookout, and they eat everything. A song bird or bat that flies too close may be batted down with a machete, a Honey Badger that stumbles up on a group of resting Efe may be chased own, an Elephant Shrew that happens on a camp will be dispatched by an archer and cooked up. The only time I ever saw the Efe not go after an animal that happened to show up is when a small herd of elephants came along, and the Efe made a lot of noise to chase them off, while at the same time making plans to hide in the nearby hide-from-the-elephant trees (yes, they have them.) And snakes. Something odd going on there with snakes (see below). </p> <p>One of the focal points of my research was to look at how animals reacted to the Efe’s presence, and it is striking. Since the Efe will kill and eat almost anything they encounter, most of the animals are very careful to avoid the Efe, and even the Efe’s habitually used trails. </p> <p>There is a certain amount of elephant hunting. Pygmies, generally, are the African elephant hunters, and apparently, have been so for a very long time. The importance of elephant is very under-appreciated by most experts. The data show that most of the food the Efe eat is plant food, and animal food makes up a percentage of their diet typical for tropical or subtropical African hunter gatherers. But those data never include elephant. I’ve estimated that the total amount of elephant meat they eat over medium periods of time, left to their own, is about the same as all the other meat combined. This happens because when someone does kill an elephant (a rare event compared to the daily killing of a duiker or other more common mammal), everyone from everywhere shows up and gorges on that meat for a few weeks. </p> <p>So, even though most researchers would classify elephant as uncommon in their diet and therefor not a major contributor to the diet, they’ve simply got that wrong. It is a big deal. </p> <p>Beyond that, the range of animals is huge, because the number of species native to the area is huge. Oddly, the Efe I was with (and these were more than one distinct group) didn’t seem to eat snakes, tough I know that others do. These Efe also often have a particular species of snake as their totem animal, and you don’t eat your totem animal. So, maybe that is the reason. </p> <p>Because Efe live the life they live, one without the privilege of access to unlimited supplies of cattle flesh, swine meat, domestic birds, and commercially caught or raised fish, they have a wide dietary niche. Because they live in a remote part of the African rain forest, this list includes a lot of animals many may have never even heard of, or that most regard as exotic, though they are very common there. They live a life where the plant foods often fail them, and collectively do not provide a sufficiently nutritious diet, so they do not have the privilege of eschewing meat, and in fact, perhaps with the knowledge that meat is the real hunger-killer in their environment, they prefer to spend as much time as they can chewing meat. </p> <p>And I spent a lot of time sharing their culture and ecology with them, and in so doing, had the privilege of getting much closer to truly experiencing another culture than most ever get. Close enough, in fact, to know that I wasn’t even close, and knowing that is a privilege the dilettante missionary or subscriber to National Geo can not have. </p> </div> <span><a title="View user profile." href="/author/gregladen">gregladen</a></span> <span>Fri, 04/28/2017 - 03:17</span> <div class="field field--name-field-blog-categories field--type-entity-reference field--label-inline"> <div class="field--label">Categories</div> <div class="field--items"> <div class="field--item"><a href="/channel/life-sciences" hreflang="en">Life Sciences</a></div> </div> </div> Fri, 28 Apr 2017 07:17:46 +0000 gregladen 34365 at I like this book so much I've read it 3 times: Neotropical Companion <span>I like this book so much I&#039;ve read it 3 times: Neotropical Companion</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><p>The Neotropical Companion by John Kricher came out years ago, in the late 80s if I recall correctly. I've got a copy of it around somewhere. </p> <p><a href="/files/gregladen/files/2017/03/Screen-Shot-2017-03-24-at-1.48.31-PM.png"><img src="/files/gregladen/files/2017/03/Screen-Shot-2017-03-24-at-1.48.31-PM.png" alt="Screen Shot 2017-03-24 at 1.48.31 PM" width="315" height="324" class="alignright size-full wp-image-23853" /></a>I loved that book because it did a great job integrating all the things in one place: animals, plants, habitats, evolution, etc. Even though I was working in the paleotropics at the time, I found it informative. </p> <p>Then, more recently, I got a revised version of the same book. I've got it around somewhere. It is from the 1990s, I think. Great book, same idea as the first one, but with more in it, and a somewhat larger format. This dates to after my fieldwork in the rainforests, but overlapped with visits to arid regions in the tropics, though again, I'm paleo and the book is neo, but still great. </p> <p>Then, I got a new copy of f Kircher's book, <a target="_blank" href=";camp=1789&amp;creative=9325&amp;creativeASIN=0691115257&amp;linkCode=as2&amp;tag=grlasbl0a-20&amp;linkId=7b11c29a337488f7006a48ae58fe3780">The New Neotropical Companion</a><img src="//;l=am2&amp;o=1&amp;a=0691115257" width="1" height="1" border="0" alt="" style="border:none !important; margin:0px !important;" />. I got this one in the future! (Not quite published yet, but I think you can actually get it <a target="_blank" href=";camp=1789&amp;creative=9325&amp;creativeASIN=0691115257&amp;linkCode=as2&amp;tag=grlasbl0a-20&amp;linkId=1a3c77e378cef001069d1178f035a4bd">now</a><img src="//;l=am2&amp;o=1&amp;a=0691115257" width="1" height="1" border="0" alt="" style="border:none !important; margin:0px !important;" />. </p> <p><a href="/files/gregladen/files/2017/03/Screen-Shot-2017-03-24-at-1.48.36-PM.png"><img src="/files/gregladen/files/2017/03/Screen-Shot-2017-03-24-at-1.48.36-PM.png" alt="Screen Shot 2017-03-24 at 1.48.36 PM" width="312" height="320" class="alignleft size-full wp-image-23854" /></a>This is a serious book. To a large extent, the intended audience is folks who plan to travel in the neotropics and want a strong background in areas of evolutionary biology and conservation. But the book is very high level in terms of the material covered, the range of facts and scope of theoretical work brought to bear, and so on. It is easy to read, even engaging to read, but it is very very rich in content. </p> <p>So, the book includes information on traveling, and seeing nature on your trip. But then it includes all that information on the nature itself. It is not a small book, not a field guide format (as the first version was), but it is worth lugging around if you are doing some serious visiting.</p> <p><a href="/files/gregladen/files/2017/03/Screen-Shot-2017-03-24-at-1.49.10-PM.png"><img src="/files/gregladen/files/2017/03/Screen-Shot-2017-03-24-at-1.49.10-PM.png" alt="Screen Shot 2017-03-24 at 1.49.10 PM" width="310" height="543" class="alignright size-full wp-image-23855" /></a>Or, if you are simply a student of the tropics, evolutionary biology, or nature (not and, but or, on all of that) this book will be an excellent addition to your library.</p> <p>And, it should be in school libraries, and on the shelves of biology teachers. There are many well developed examples of wildlife and evolution in here, that can be expand on with further literature review (and the book provides a handle on that) for developing in class projects. </p> <p>I've put the table of contents below. As you can see, the book is well organized and covers a lot of material. Also, it is a well produced (as is typical for this publisher, Princeton) and nice looking. </p> <p>The author, John Kricher, is a biology professor at Wheaton. He's also written: <a target="_blank" href=";camp=1789&amp;creative=9325&amp;creativeASIN=069112633X&amp;linkCode=as2&amp;tag=grlasbl0a-20&amp;linkId=71e6b81406952ef71a04d8a42043f5a6">Galápagos: A Natural History</a><img src="//;l=am2&amp;o=1&amp;a=069112633X" width="1" height="1" border="0" alt="" style="border:none !important; margin:0px !important;" />, <a target="_blank" href=";camp=1789&amp;creative=9325&amp;creativeASIN=0691115133&amp;linkCode=as2&amp;tag=grlasbl0a-20&amp;linkId=fe4094e91ab890be8769a03e345fe3b6">Tropical Ecology</a><img src="//;l=am2&amp;o=1&amp;a=0691115133" width="1" height="1" border="0" alt="" style="border:none !important; margin:0px !important;" />, <a target="_blank" href=";camp=1789&amp;creative=9325&amp;creativeASIN=0395928966&amp;linkCode=as2&amp;tag=grlasbl0a-20&amp;linkId=f379cac04c0e28973703b01edfe32d9e">A Field Guide to California and Pacific Northwest Forests (Peterson Field Guides)</a><img src="//;l=am2&amp;o=1&amp;a=0395928966" width="1" height="1" border="0" alt="" style="border:none !important; margin:0px !important;" />, <a target="_blank" href=";camp=1789&amp;creative=9325&amp;creativeASIN=B008VQS1UG&amp;linkCode=as2&amp;tag=grlasbl0a-20&amp;linkId=28da5b7d0cd5254e4dcbd5e3f435c2ca">By John Kricher - The Balance of Nature: Ecology's Enduring Myth</a><img src="//;l=am2&amp;o=1&amp;a=B008VQS1UG" width="1" height="1" border="0" alt="" style="border:none !important; margin:0px !important;" />, and a couple of book on tape thingies such as <a target="_blank" href=";camp=1789&amp;creative=9325&amp;creativeASIN=B001JHT8E2&amp;linkCode=as2&amp;tag=grlasbl0a-20&amp;linkId=be01c2790bcf45ad875fae4513b1de63">Ecological Planet - An Introduction to Earth's Major Ecosystems: The Modern Scholar</a><img src="//;l=am2&amp;o=1&amp;a=B001JHT8E2" width="1" height="1" border="0" alt="" style="border:none !important; margin:0px !important;" /> (well, not really tape, of course).</p> <p><a href="/files/gregladen/files/2017/03/Screen-Shot-2017-03-24-at-2.03.37-PM.png"><img src="/files/gregladen/files/2017/03/Screen-Shot-2017-03-24-at-2.03.37-PM.png" alt="Screen Shot 2017-03-24 at 2.03.37 PM" width="272" height="360" class="alignright size-full wp-image-23856" /></a>TABLE OF CONTENTS:</p> <p>Preface 9<br /> Acknowledgments 11<br /> How to Use This Book 12<br /> 1 Welcome to the Torrid Zone 15<br /> 2 Why It Is Hot, Humid, and Rainy in the Tropics 29<br /> 3 Rain Forest: The Realm of the Plants 39<br /> 4 Finding Animals in Rain Forest 58<br /> 5 Sun Plus Rain Equals Rain Forest 73<br /> 6 Essential Dirt: Soils and Cycling 81<br /> 7 If a Tree Falls . . . Rain Forest Disturbance Dynamics 95<br /> 8 Evolutionary Cornucopia 113<br /> 9 Why Are There So Many Species? 134<br /> 10 Tropical Intimacy: Mutualism and Coevolution 155<br /> 11 Evolutionary Arms Races: More Coevolution, More Complexity 181<br /> 12 Cruising the Rivers to the Sea 205<br /> 13 Scaling the Andes 235<br /> 14 Don't Miss the Savannas and Dry Forests 250<br /> 15 Neotropical Birds: The Bustling Crowd 262<br /> 16 From Monkeys to Tarantulas: Endless Eccentricities 319<br /> 17 Human Ecology in the Tropics 365<br /> 18 The Future of the Neotropics 377<br /> Appendix Words of Caution: Be Sure to Read This 389<br /> Further Reading 392<br /> Index 417</p> </div> <span><a title="View user profile." href="/author/gregladen">gregladen</a></span> <span>Fri, 03/24/2017 - 09:04</span> <div class="field field--name-field-blog-categories field--type-entity-reference field--label-inline"> <div class="field--label">Categories</div> <div class="field--items"> <div class="field--item"><a href="/channel/life-sciences" hreflang="en">Life Sciences</a></div> </div> </div> Fri, 24 Mar 2017 13:04:13 +0000 gregladen 34320 at