Biogeography
Category archives for Biogeography
Triassic Life on Land: I love this book
Posted by Greg Laden on July 28, 2010 The Triassic is old. This book is new. That is a hard to beat combination.
How geology affects your dog’s demeanor and the view from your back yard
Posted by Greg Laden on July 5, 2010 Does your back yard slope up, away from your house, or does it slope down? The likelihood that your yard slopes one way or the other … statistically … depends in large part on what region you live in. (Here I’ll be speaking mainly of the US, but the principle applies broadly.) If you live…
Pink Iguanas and Disappearing Islands
Posted by Greg Laden on January 6, 2009 It turns out that a recently discovered population of land iguanas on the Galapagos is probably a new species that represents the basal (original) form of Galapagos land iguana. Moreover, this iguana is found in an unexpected place, according to a paper just coming out in the Proceedings of the National Academy of Sciences (PNAS).…
Neanderthals at the end of their days
Posted by Greg Laden on December 13, 2008 What was Neanderthal-Modern Human interaction really like? Fifty four teeth (some of which are fragments) and nine other bones dating to about 40-43,000 years ago represent the “most recent, and largest, sample of southern Iberian late Neanderthals currently known.” These and some closely related remains may indicate that these Middle Paleolithic holdouts were kissing cousins…
Allen’s Rule, Phenotypic Plasticity, and The Nature of Evolution
Posted by Greg Laden on December 5, 2008 Allen’s Rule. One of those things you learn in graduate school along with Bergmann’s Rule and Cope’s Rule. It is all about body size. Cope’s Rule … which is a rule of thumb and not an absolute … says that over time the species in a given lineage tend to be larger and larger. Bergmann’s…
The Scientific, Political, Social, and Pedagogical Context for the claim that “Race does not exist.”
Posted by Greg Laden on November 29, 2008 These days, many people say that race is largely a social construct; while it may have a place in describing the population genetics of some species, is not particularly applicable to humans. I’m one of those people. The race concept is generally inapplicable or at best misleading when used as it often is with our…
The Flores Hominid and the Evolution of the Shoulder
Posted by Greg Laden on October 22, 2008 Homo floresiensis more widely known as the “Hobbit,” may have had arms that were very different from those of modern humans. A paper in the current issue of the Journal of Human Evolution explores the anatomy of H. floresiensis. To explore this we first have to understand the concept of “Humeral torsion.” Humeral torsion is…
Cultural Evolution from Mosquitos to Worm Grunting
Posted by Greg Laden on October 13, 2008 A very good day of grunting worms. Credit: Ken Catania So-called Gene-Culture Co-Evolution can be very obvious and direct or it can be very subtle and complex. In almost all cases, the details defy the usual presumptions people make about the utility of culture, the nature of human-managed knowledge, race, and technology. I would like…
Re-examining the cause of speciation and species diversity in the tropics
Posted by Greg Laden on July 29, 2008 Did Past Climate Changes Promote Speciation in the Amazon? Any time you’ve got a whopping big river like the Amazon (or a mountain chain like the Andes, or an ocean, or whatever), you’ve gotta figure that it will be a biogeographical barrier. Depending on the kind of organisms, big rivers, high mountains, oceans, forests, deserts,…
Why the Hobbits of Flores Were Probably Not Broken People
Posted by Greg Laden on March 6, 2008 There is a new paper out suggesting that the Flores hominids, known as Hobbits, were “human endemic cretins.” From the abstract of this paper: … We hypothesize that these individuals are myxoedematous endemic (ME) cretins, part of an inland population of (mostly unaffected) Homo sapiens. ME cretins are born without a functioning thyroid; their congenital…
Very Large Parks are the Wave of the Future
Posted by Greg Laden on February 28, 2008 Across Africa, and to some extent Asia, existing large parks and preserves are being combined into very large parks in order to serve several important functions. One is to make the parks so large that there will be interior areas that are impractical for most poaching or other encroachment. Another is to allow movement of…
Darwin and the Voyage: 11 ~ Elephants and Horses
Posted by Greg Laden on February 22, 2008 In 1833, Darwin spent a fair amount of time on the East Coast of South America, including in the Pampas, where he had access to abundant fossil material. Here I’d like to examine his writings about some of the megafauna, including Toxodon, Mastodon, and horses, and his further considerations of biogeography and evolution.
Darwin and the Voyage: 10 ~ Rheas and the Birth of Evolutionary Theory
Posted by Greg Laden on February 20, 2008 Everyone knows about Darwin’s Finches, of the Galapagos Islands. But of course, Darwin made observations of birds throughout his travels on The Beagle. Here, I present a number of passages from The Voyage that include some of these observations.
The Potato and Human Evolution
Posted by Greg Laden on February 19, 2008 Fallback foods are the foods that an organism eats when it can’t find the good stuff. It has been suggested that adaptive changes in fallback food strategies can leave a more distinct mark on the morphology of an organism, including in the fossil record, than changes in preferred food strategies. This assertion is based on…
Darwin and the Voyage: 09 ~ Fossil Quadrupeds
Posted by Greg Laden on February 18, 2008 Charles Darwin wrote a book called Geological Observations on South America. Since Fitzroy needed to carry out intensive and extensive coastal mapping in South America, and Darwin was, at heart, a geologist more than anything else (at least during the Beagle’s voyage), this meant that Darwin would become the world’s expert on South American geology.…
Darwin and the Voyage: 06 ~ Bugs
Posted by Greg Laden on February 10, 2008 When reading the Voyage, it is impossible to miss the observation that much of the time Darwin was engaged in adolescent boy behavior: Pulling the heads off insects, noting how long they would wiggle after cut in half, closely examining the ooze and guts, occupied much of his time. Obviously, careful observation and a strong…
Are We In The Anthropocene? No.
Posted by Greg Laden on January 31, 2008 Proposals to give the latter part of the present geological period (the Holocene) a new name … the Anthropocene … are misguided, scientifically invalid, and obnoxious. However, there is a use for a term that is closely related to “Anthropocene” and I propose that we adopt that term instead.
Hybrids of Blind Fish Can See
Posted by Greg Laden on January 27, 2008 The loss of sight in cave dwelling species is widely known. We presume that since sight in utter darkness has no fitness value, the mutation of a gene critical to the development of the sense of sight is not selected against. Over time, any population living in darkness will eventually experience experience such mutations, and…
Did Humans or Climate Change Cause the Extinctions of Pleistocene Eurasian Megafauna?
Posted by Greg Laden on January 25, 2008  Did humans wipe out the Pleistocene megafauna? This is a question that can be asked separately for each area of the world colonized by Homo sapiens. It is also a question that engenders sometimes heated debate. A new paper coming out in the Journal of Human Evolution concludes that many Pleistocene megafauna managed to…
After the End Permian Mass Extinction
Posted by Greg Laden on January 23, 2008 The end-Permian mass extinction event was the big daddy of all the known mass extinction events. Life on the planet Earth was almost entirely wiped out. A new paper explores the post-extinction recovery of ecological systems.
Genome Size, Adaptations, Constraints, Exaptations, Aptations, and so on…
Posted by Greg Laden on January 18, 2008 There is a discussion on the internet about Junk DNA, that includes a discussion at Sandwalk (Larry Moran’s blog) … I made a comment there about genome size that was responded to by T.R. Gregory. I started to write my response in Larry’s Little Box, but realized that it would not fit. So it is…
Avalon and the origin of multicellular life
Posted by Greg Laden on January 3, 2008 New research published in Science on the origins of multicellular life reveals an interesting pattern. The Cambrian Explosion may have been samosamo.
The Bahamas Yield Amazing Fossil Finds
Posted by Greg Laden on December 21, 2007 Plant and animal fossils recently discovered from an island in the Bahamas tell a story of habitat change and human involvement in local extinction.
The Flores Hominid and the Evolution of the Shoulder
Posted by Greg Laden on December 19, 2007 Homo floresiensis more widely known as the “Hobbit,” may have had arms that were very different from those of modern humans. A paper in the current issue of the Journal of Human Evolution explores the anatomy of H. floresiensis. To explore this we first have to understand the concept of “Humeral torsion.” Humeral torsion is…
Where The Cooties Go To Die
Posted by Greg Laden on December 18, 2007 OK, so you are vacuuming the house, and along the way, you suck up a couple of spiders, some spier eggs, a beetle or two, and as the cat or dog walks by, you figure you’re probably sucking up some fleas and flea eggs, and so on and so forth. SO you know all these…
Scientists Investigate Gorilla Biogeography
Posted by Greg Laden on December 13, 2007 The Central African Rainforest (as distinct from the West African Rain Forest) spans an area from the Atlantic coast to nearly Lake Victoria in Uganda and Tanzania. In fairly recent times (the mid Holocene) this forest was probably continuous all the way to Victoria, and probably extended farther north and south than one might imagine…
Human Evolutionary Rate Study
Posted by Greg Laden on December 11, 2007 There seems to be some interesting things going on with the recently reported study of rates of evolution in humans. We are getting reports of a wide range of rather startling conclusions being touted by the researchers who wrote this paper. These conclusions typically come from press releases, and then are regurgitated by press outlets,…
Darwin’s Dust
Posted by Greg Laden on December 4, 2007 All I have is the press release, but it’s fun: Cosmopolitan microbes — hitchhikers on Darwin’s dust Scientists have analysed aerial dust samples collected by Charles Darwin and confirmed that microbes can travel across continents without the need for planes or trains – rather bacteria and fungi hitch-hike by attaching to dust particles. In a…
Modern Humans and Neanderthals: Did they “do it?”
Posted by Greg Laden on November 18, 2007 Or, to be less crude, did modern humans, having already evolved in Africa, interbreed with the local Europeans who were Neanderthals, and if so, did they produce fertile offspring … and, did this happen in sufficient degree to have mattered at all to the genetics of later (but not necessarily living) people?
Crocs Afar
Posted by Greg Laden on November 15, 2007 Repost from gregladen.com One day, about six thousand years ago (or more like 15 thousand … the timing of this is disputed) a volcano in the vicinity of Mwea, Uganda blasted a huge volume of stuff into the air, covering the surrounding landscape and choking off most of the life forms living in a nearby…
, which is now available for the 
