Last week, we watched Evolve: Eyes on the History Channel; tonight, shall we watch the next episode, Evolve: Guts, together? Tune in shortly!
A disgusting beginning: competitive eaters? Bleh. It's a basic introduction to mammalian digestive physiology — I can tell we're going to get lots of Big Vertebrate biology again.
They show a cool machine called Cloaca that simulates human digestion, with vats containing chemicals to act as the various chambers. They don't bother to explain why this machine was built, but it is kind of weirdly interesting.
Once again, they openly say that the complexity of the digestive system evolved — that's rather refreshing.
Yay! They go back to microorganisms 700 million years ago...for 30 seconds. Then we move on to Ediacaran organisms. The evidence shows that they weren't photosynthetic, but were some kind of animal that had to have fed somehow, and probably were passive absorbers of drifting nutrients. They suggest that they were replaced by Cambrian organisms that had guts.
Jellyfish just have a sac, not a tube. Cambrian creatures had a more elaborate feeding system, allowing for sophisticated mobile predators, and we see an arms race. Nice animations of Anomalocaris all over the place!
Zip to the modern day: submersibles discover exotic deep sea worms that live on dead whale bones. They have no mouth or gut, so how do they eat bone? They were drilling in and bringing bacteria with them that broke down the bone, and then the worms absorbed the bacteria.
Hey, they mention bacteria, and talk about how digestive enzymes secreted by bacteria are predecessors, and are necessary for the extraction of food in our own guts.
They also mention fish and specialization of regions in the gut tube! More fish, please! But no, we're going to go straight to tetrapods now, and the promise before the break is dinosaurs. Oh, well.
I'm really pining for more about the actual evolution of guts — and something about development. How can they talk about epithelial tubes without talking about development? Jumping to dinosaurs skips all the interesting stuff. Guts are done by the time you've got dinosaurs.
OK, dinosaurs. Yeah, yeah. They discuss gizzard stones and the relationship of dinosaurs to birds. Were dinosaurs warm-blooded? Their digestion was less croc-like and more bird like, determined by analyzing dinosaur coprolites, including T. rex droppings, which contain fragments of fossilized bone. They contain large quantities of bone, which suggests a croc-like eating pattern. But they also contains fragments of fossilized muscle tissue, which suggests that food passed through rapidly, like a bird. So it was a glutton that also had to eat frequently.
The K/T event meant that these big consumers all starved to death. The lead-in to the next section is all about snakes and mammals.
Snakes! Theyre going to talk about the evolution of feeding strategies (why not use cichlids, though? They'd be better). Oh...because you can show movies of snakes swallowing mice whole.
Nifty x-rays of poor mice dissolving in a snake's gut.
Discussion of the ability of the snake to shut down its gut between meals. Microvilli lining the intestine actually contract while fasting, and increase in length when feeding.
20 million years ago, there was a widespread increase in grasslands that represented a new opportunity ... but was hard to eat because much of it was bound up in cellulose. Ruminants evolved fermentation chambers. They show a surgically fistulated cow that allows researchers to get their hands right into a gut. They use bacteria to help break down tough plant material.
These adaptations promote the growth of herbivores...which leads to the evolution of predators.
Now it's on to humans, of course. They suggest that maybe the key innovation in our ancestors wasn't our brain, but guts: big-toothed, small-brained apes evolved into small-toothed, big-brained humans. A switch in diet to more meat, and the use of tools to 'pre-digest' food allowed us to have smaller guts. Cooking was another huge change that greatly improved the quality of the diet.
They measure the energy required by snakes to digest raw vs. cooked meat. Cooking reduces the cost of digestion by 12.5%. Human guts evolved to be more efficient, liberating more energy for the evolution of the brain.
OK, much like last week's episode, this show's strengths are also its weaknesses. The emphasis on charismatic megafauna may be great for catching the attention of casual viewers, but it leaves out all the important events in the evolution of these structures, and ends up emphasizing late refinements and details. Somehow, we need to get a documentary that brings up more molecules and development and the all-important teeny-tiny creatures, where the major innovations first appeared.
But still, I'm most impressed to see a television show that unapologetically discusses evolution as the only credible explanation for the appearance of these features.
- Log in to post comments
Looking forward to it.
Nobody posted the last one to the usenet. :(
Hooray guts! I'm a developmental neurobiologist, myself, but I think the gut is pretty cool too.
Looking forward to watching it with all of you.
No way, the Twins play the Mariners in 15 minutes!
Tivo is locked and loaded though.
No way, the Twins play the Mariners in 15 minutes!
Grrrrrrrrrrrr. All I get is the Red Sox. Not that there's anything wrong with that (esp now that Manny's gone *ducks*)
Can't wait!!!
the gut is the second brain for sure.... as far as i can tell, there is lots to discovery about the neurohurmonal interface.
No need to duck, Bay's lighting it up.
Also, new comment format PZ?
Craig - I can't get it either. Ane-tenney don't pick it up. :(
If all of you post such great comments as you did on the Comfort radio show it'll be fun anyway. ;) Thanks!
Bunch of fatties :P
I thought we were "Intelligently Designed"? What's all this talk of evolution?? (smirk..)
I'm skipping this one, I'm going to predict lots of dinosaurs...
Go Yankees!!! And anyone else hungry for a burger??
They went right past the little guys :(
Thought for today:If you believe force is justified when you believe you are right, you validate those who use force when they believe you are wrong.
This is a tough one...I'm doing a lot of flipping. The Nat. Geo. Channel has something on life under the Koran, the Science Channel has something on Phoenix, the Mars lander....and I see Cinemax has an alien sex movie at 9:30!
Nobody posted the last one to the usenet. :(
try hre
I expect the next one will be available somewhere too.
just google search on "History channel evolution X torrent"
where "X" is the name of the specific episode, like "eyes".
For anyone interested in the latest from the Phoenix lander, here's today's NASA press phone conference. Neat stuff.
http://www.jpl.nasa.gov/news/phoenix/podcast-phx20080805.php
"... the Ediacarans were trying to .....".
grrrrrr
er, make that:
"History channel evolve X torrent"
that should produce the best results.
try late tomorrow for tonight's episode.
Ewww, guts. Sounds yucky.
What about protostome guts? Or acoelomate or pseudocoelomate guts? They're far more interesting. Bill Nye taught me how my guts work, I don't need it again...
Thanks, but I don't use bittorrent, only usenet.
They send you to Guantanimo for using bittorrent.
Didn't digestion (or metabolism) actually begin before microorganisms...I saw a talk on the reverse Kreb cycle...where like a ball rolling down a hill is an expected outcome due to lower energy...so is reverse Krebs...it results in lower energy states.
Its science lite. But I still stand by my own experience: You get the populace interested in biology (and science in general) with things they can see and imagine and go "Wow that's cool" It's the same reason that the creationists try to hijack dinosaurs whenever they can (say the creation museum). We need to fight them in the hearts and minds of the public.
My field at last -art. The Cloaca machines were produced as art installations; the first one was in a museum in Antwerp, I believe. I shit you not.
@#20
Yeah, but if you get the torrent, they don't get the ratings, so it decreases the chances that they'll greenlight similar programming.
Oh and the Phoenix podcast will probably be interesting to people who understand microbiology.
I don't though... but I still think its interesting (listening right now).
Ratings PZ. Dino ratings.
Well, everybody likes dinosaurs, so gotta give the people what they want. Nothing came before dinosaurs anyway, right?
Cloaca:
http://en.wikipedia.org/wiki/Wim_Delvoye
Thanks SC. I couldn't remember who the artist was. Some wag said this installation proved conceptual art was truly shit.
kindly shut your common sewer up, and become a monotheist.
More fish, please!
ditto!
That freaky cow looked at me weird...
That poor cow...
cow hole!
They send you to Guantanimo for using bittorrent.
I can haz free vacation now?
:p
Some wag said this installation proved conceptual art was truly shit.
*snarl* (with grudging pun credit)
/art history major
Oooh, that segment made my stomach hurt.
?
I'm reeling from the Luxemborgian poop machine and the glass-bottom cow.
The show was good, but I wish they would have spent less time with dinasaurs. Yes, they are interesting, but I thought they were somewhat irrelevant to the program. More invertebrates would have been good.
@ E.V., comment #41
Yeah, I was really confused by that statement, too. I was thinking Poe's Law might apply here but then I realized it's not even clear what the statement is, let alone what was meant.
Good night sweethearts! I gotta make whip cream, to eat with the pie (you pervs), and watch House. Have fun with guts! ;)
I think we may have been the victims of a drive-by trolling.
I agree. It constantly reminds the viewer of the opportunities and innovations that provide the raw materials for natural selection without so much as a nod to the IDiots.
It doesn't really matter to me about the details or the skimming over of the microbiology as long as they get that point across to the casual viewer. Might just convince some laypeople.
any hagfish in this one? I've been facinated with them since Grade 11 marine biology when we actually trapped one of the slimy bastards,
If anyone is looking for a monotheistic god to worship, I'd be happy to be that god.
Screw those hippies with their Trinity. Three gods are lame.
The problem with shows like this is that they don't spend enough time emphasizing the importance of mutation and natural selection. I'm afraid that the casual viewer will watch it and go away thinking that evolution is some magical process.
I just watched it with a paleontology enthusiast. He liked it a great deal, but I was pining for more molecular details. Still, thumbs up from me.
I especially like the brief explanations of the various experiments that were performed. The growing microvilli, the change in CO2 output, and the presence of soft muscle tissue in coprolite were as fascinating as they were relevant to the issues discussed. It's not just telling us what scientists know; it's showing us glimpses of how they know it. More stuff like that, please.
Ediacarans: The Creationists Nighmare! (Designer: "Oops. Scratch that. Start again."}
Yeah. No religious woo-woo. No priests or preachers. No mention of magical creation. Not bad for Idiot America.
Thanks for the breathless, blow-by-blow live-blogging, PZ!
Yeah, I like this series, too.
((I also channel surfed and caught a little SMASH LAB, the Mythbusters-wannabe show; though to their credit, they do go more in depth into the scientific method and experimentation, but this makes for more boring TV than Mythbusters, which is way more fun.))
Staying up to watch new episode of the reality crime show THE FIRST 48 on A&E at Midnight (Central). I'm addicted to that show.
I can't watch it yet as I only have net on my phone now but, did they have an appendix at the end? I love the way stuff like that annoys IDiots.
PS I think the 'common sewer' line was a very obscure quote or something.
What kind of Mandu crap are you talking? Next you'll be telling me Alvis was a Kreb.
[/pop culture free-association]
I think I share the desire for more of the story of the development.
It would be cool to have a television version of Neil Shubin's book.
(That was @24)
The market for TV viewer attention span has got to be a soul-killing aspect to any great story. Evolution chief amongst them.
Imagine, you have six hour (really 6 fifty minute segments each cut into about five sub-segments) where you have a chance to inform the general public about the amazing history, significance and intricate detail of the process of evolution.
I think, as a concept its well done. As a teaching mechanism its obviously lacking. I suppose it shouldn't be analyzed as a teaching mechanism, but more of a device to get the stagnant mind to wonder, and perhaps to investigate the process in greater detail.
Think of it more like a tasteful and edifying version of those Christian tracts one finds lying around in bar bathrooms and bus seats.
Not to bad. The portal in the side of the cow was a bit unsettling. Not so much the hole in its side, but the scientist punching out the cover was a bit disturbing.
I wish they would have made these shows 2 hrs long. One hour is just not enough time to show a few hundred million years of evolution.
Think of it more like a tasteful and edifying version of those Christian tracts one finds lying around in bar bathrooms and bus seats.
In some alternate mirror-image universe, Jack Chick as science popularizer ;) with tract captions such as "You think there is evidence for evolution?!! Get out of my classroom, and go home and read your Bible until you feel sorry enough to apologize to the class for your stupidity!"
I sweat, every time I sit down to have a meal, and I happen to have the TV on, some sort of gore or greusome detail is portrayed on the damn screen.
I had to run it back after my meal to appreciate the visible cow.
But then, if that's the best god can do, I'm not worried...
My original focus in college was telecommunications. Long story short, I became bored of it, and dropped out for a year. I now find biology and evolution in particular far more interesting, and will be going back to school next month to begin my bachelors degree in Bio, but perhaps I need to bring them together... a double-major in telecommunications and evo-devo, maybe? My main motivation nowadays is to help and/or educate people... seems we need better documentaries on the subject, and people like David Attenborough have always been an inspiration to me. I've been thinking I'd be good as either a researcher or professor, but perhaps this would be a better path.
T. Rex droppings: In the beginning was the turd.
#61
Sounds like the John Freshwater classroom...
Perhaps John is a traveler in both dimension and time.
Or perhaps he just an asshead.
I read this blog everyday but this is my first post. Anyway I actually got my girlfriend to watch this(and she is a fence sitting agnostic who is skeptical of both sides) & she enjoyed it and she had many questions about evolution & they were answered. How do I keep her interested?
T. rex droppings, which contain fragments of fossilized bone my arse. I have it on good authority that those fragments were actually coconut shell.
I was very interested in this program but a bit disappointed by the comments on this site.
While I agree that someone of PZ's stature would find this a little lame it is good to remember the general level of the audience. If the goal is to try and explain evolution to someone who does not get it I think they did a good job. If someone was to study this in more depth they would be able to start from this point, but the goal here is surely to get them interested enough to do that.
I do agree though finally to see something with no religion is refreshing.
Please pardon the number of ''ands'', I'm doing this from my phone
Give her something to read that's interesting and easy for a non-scientist to understand.
I know next to nothing about science, but I had no problem understanding and enjoying what Ken Miller said at the Dover trial.
Nowhere near as funny as Paris Hilton's new video:
http://www.funnyordie.com/videos/64ad536a6d
Wow, she almost completely redeems herself in just 1:51.
Ummm Im watching this show right now. Their not going in depth on the transitions of the gut. Dont you think Creationist will jump all over this. I can hear it now. "see see where did all the information come from."
PZ! Here's something just up your alley:
http://www.tonmo.com/forums/attachment.php?attachmentid=1316&d=11256687…
@ 66 - How about a trip to a good museum? Make sure you buy her a nice lunch and pay for the ticket too :)
I didn't get to see this (no tv), but didn't human's evolve large brains before they reduced their tooth size? I mean, I guess they sort of coincide, but i've always understood that as a need to get room for the brain. we had large canines for quite a while after - i don't remember my molar info well enough though...
Give her something to read that's interesting and easy for a non-scientist to understand.
or watch.
I found many of my less science-aware friends enjoyed the NOVA special on the Dover trial quite a bit.
Yes, for sure. The NOVA show about Dover had some good science, and it also had strong evidence for the idea that Christians are lying pigs.
Off topic but extremely good news: Trove of Endangered Gorillas Found in Africa
125,000 gorillas were discovered that nobody before knew about. Wow!
Nothing is better than snakes.
I was waving Shep at the TV, telling him to take his cousin in the X-ray as a good example and eat his damned rat already before we have to send it to college. There's nothing quite like a young adult male ball python with the vapors. I wonder if there's a local dating service for snakes--maybe Craigslist?
I learned a thing or two from that, which can't be taken for granted with TV. But I'm really really tired of macho dinosaurs. Come on, boys, they probably tweeted, and besides, have you ever seen a predator roar before pouncing on prey? Talk about defeating the purpose.
Yeah, though, nice drive-by shots of Burgess Shale citizens.
Yes, for sure. The NOVA show about Dover had some good science, and it also had strong evidence for the idea that Christians are lying pigs.
LOL
indeed it did.
I've used it to actually solidify the atheism of more than one person with the obvious fact that xianity =/ morality.
*evil laugh*
still, though, it did an excellent job of simply and concisely defining the science issues surrounding the case, in a way most of my friends very readily grasped.
It actually surprised me how much they enjoyed the presentation.
Well,it skipped ahead to dinos and modern animals a bit too quickly for my liking but I am so thrilled they are doing a show on evolution that I am not going to complain. I wonder how long it will before before we start seeing IDiots protest about the show and a crazy demand for equal time.
"But still, I'm most impressed to see a television show that unapologetically discusses evolution as the only credible explanation for the appearance of these feature"
Is it really that rare for US telly to unambiguously espouse the virtues of evolution? It's no wonder we don't get many US imported science shows in the UK then.
Wow - evidence of soft muscle tissue in fossilised dino-poo! That is so cool. I am going to have to look that one up: the little kids I know will love it :-)
Has anyone linked to the new Dawkins series 'The Genius of Charles Darwin' yet?
Its on the Dawkins site now as youtube clips and a torrent.
http://tinyurl.com/5mmhxo
It seems so strange to me that an educational TV programme that actually talks about evolution as fact is seen as a rare blessing. When I was a child, evolution was just a given. There was no controversy. Jokes that required a functional understanding of evolution were all over the place in kid's programming.
And I lived in a very conservative / religious country.
How on earth did things get this bad? The pro-fact side has horrendous PR.
BobC #76: "125,000 gorillas were discovered that nobody before knew about. Wow!"
No doubt about it, that is wonderful news in a world where good news has become increasingly scarce.
Unfortunately, many will take it as a justification to breathe a sigh of relief, worry LESS over their plight, and ease off on the sense of urgency (and the financing) in efforts to save them and their habitat.
My children loved the first episode of Evolve. Last week's T-Rex was interesting, but I think the eagle eyes and 29K lenses of the dragonfly captured their attention most. At their age (elementary school) its not the science, its the superlatives.
Professor Myers: The reason the Cloaca machine was made is to produce an unending supply of a chemical called Theobeale, for use as an incapacitant. This chemical is similar to skatole.
Oh, sweet Flying Spaghetti Monster! PZ, you are my hero! Readers, have you noticed, as I just did a minute ago, that the tag lines are now at the top of the posts as I begged so prettily to have done? Now, when a recognized troll posts, all I have to do is scroll down, and poof! it's gone!? Ah, the glory of a low-tech solution!
Tony at #57, that's a great idea! Neil has a great talent for communicating science to reach people at many different levels of scientific literacy, so a TV movie of his book has alot of potential to excite alot of people.
PZ, I think your closing paragraphs nail it on the head.
@#87
...or you could do what many of us do, Lee, and get a killfile for your browser that allows to you block users and hide comments.
Then you don't have to rely on others to do the "work" for you.
Previous commenters are correct, the Cloaca project was an art installation. I actually saw it at the New Museum in NYC. They were having a hilarious problem: The machine is designed for extremely bland and simple diets, but the people running the museum thought it would be fun to have chefs from nearby restaurants fix meals for the machine. It almost immediately developed diarrhea, and they had to cover half of the machine so that "sensitive" viewers wouldn't start hurling.
Three? http://xkcd.com/459/
LOL...this is kind of silly, but the first thing I envisioned when I read "Big Vertebrate" biology in PZ's post was other areas of biology indignantly protesting against the oppression of "Big Vertebrate" ala "Big Oil", "Big Pharma", and of course the creationist's favorite, "Big Science". :^)
#83: The pro-facts side got a little complacent, I think. We thought facts didn't need PR. Why spin something when anyone with eyes to see could just look out and see it?
How naive we were. Sigh. . . .
I don't have a TV at the moment, so I'm hoping to torrent it. But why shouldn't those who can do both? Watch it on TV to get the ratings up, then torrent the digital file for your own records. Shows like these deserve to be seen again and again.
That Nova show about the Dover trial is currently available on the documentary usenet binaries groups.
Those fistulations (fistulae?) scared the shit out of me when I saw them on telly as a kid. I was so worried someone would do that to out cows ...
I thought their "Eyes" show could have had more about actual evolution, but this one really could have used some evolution.
Basically the story was that this or that organism needed to digest something, so it evolved the guts which enabled said digestion. It was too close to the caricature of evolution the IDiots give us, that it's all just "evolution of the gaps." Don't know what happened? Say it evolved.
No, sorry, the point of evolution is that you can address details to a significant extent, and of course you can meaningfully compare anatomy and physiology. They didn't.
Basically this was a natural history show--and good in those terms. The evolution was mostly just thrown in, with the exception of the contrast between Ediacaran fauna and Cambrian fauna.
I want some real evolution. I know they can't address it in the way that Nature would, but they could include important evolutionary events, and a bit of the evidence (genetic, fossil) for it. The series is good, but it could be rather better.
Glen D
http://tinyurl.com/2kxyc7
I agree, Glen (#97). The gut evolution story is such a cool one, and if they could have found a way to introduce the co-evolution story of beneficial bacteria with metazoan guts I would have been in heaven*
(see, e.g. http://www.sciencemag.org/cgi/content/full/320/5883/1647)
Alas, I'm sure the average american viewer would have been inordinately freaked out by the revelation that he or she harbors roughly 1 kg of bacteria in his/her gut tract. The 'Colon Cleanse' woo is already way too prevalent as it is.
I think team HC is probably making the best choices for their target audience, and if laypeople are interested/intrigued by the presentation rather than scared off because it's too 'sciency' or confrontational, I'd say that's a positive outcome, particularly given the other programming on this channel (Vampires????) I wish the History Channel would provide 'for more information' links for the 'Evolve' series, either after the program or on their website. Has anyone found these?
I, too, appreciate that the "Evolve" producers are not pulling any punches about the facts of evolution, but it makes me a little sad--and scared--that this is something to be legitimately joyful over. It's sobering to realize that a program giving equal time to the ID/creationist view *could* be produced and aired by a secular/non-denominational broadcasting company in this day and age. I think we're all so happy about the fact that "Evolve" isn't such a program because we all realize how feasible--and, arguably, "PC" in that insipid American way--it would be.
*in the interest of full disclosure, I fell asleep about 30 minutes in. If my assumptions about the latter half of the program are incorrect in any way, I'm sure I'll hear about it from y'all :)
My boyfriend told me about Cloaca about a year ago. Apparently, people were paying good money to buy pieces of poop that it produced.
I wonder if anyone ever just sent their own poop? *hmmmmmm....*
My boyfriend told me about Cloaca about a year ago. Apparently, people were paying good money to buy pieces of poop that it produced.
WJW. Did they not understand the part about how it exactly reproduces all the processes of the human gut? And so produces actual feces and not some kind of faux-poop? But since it is a machine it must not be as disgusting as "real" poop. And these are probably the same people who think "natural" vitamins are healthier than "artificial" vitamins.
Kate #90
I am an unsophisticaed PC user and did manage to install Firefox to get here when IE fails. However the intricacies of killfiles is beyond me. I would never suggest someone make a modification just for me; that would be selfish and self-centered. But it did occur to me that it would be a useful change allowing EVERYONE to benefit. So to accuse me of trying to get someone to do my work for me is not merely inappropriate, it makes me think that you might be one of those trolls it will be easy to blow by in the future. If I am wrong, I shall be happy to apologize. So, dear readers, is her snark warranted?
I agree. Even I as a non-biologist was disappointed at how much stuff was skipped or glossed over. What about hydra guts? flatworm guts? sea anemone guts? earthworm guts? clam guts? insect guts (totally awesome - they get rebuilt completely during metamorphosis!)? frog guts? squid guts? comparisons of herbivore, carnivore, and omnivore guts among modern related species? enzymes and other cool chemical stuff? And the level of detail in what they did cover was inconsistent, to say the least. For all that it pains me to say it, the result was almost as choppy as something an IDiot might have come up with.
What this series needs in order to cover its subject matter decently is a two-hour episode for each system, but I'm afraid most people don't have the attention span for that. Maybe two one-hour episodes would work. (Turning the entire production over to the Beeb wouldn't hurt either. They'd have a better chance of doing it right, snark snark!).
Oh, and competitive eating is just gross. Why they put that in, I haven't a clue. OTOH, +1 for the animation of something that looked like it might have been Tiktaalik even though they didn't identify it.
Hear, hear! Every time I see a roaring dino, I want to throw something at the TV screen. Luckily I limit myself to yelling instead, otherwise I'd be permanently broke from buying a new TV every other week.
Nope. Anyone feel free to correct me if I'm wrong, but I've been under the impression that roaring is a threat display used either for [1] guarding territory, food, mates, etc. against rivals, or or occasionally [2] faking out predators by making an animal seem fierce and thus give them second thoughts.
#102 -- what about whales? There's evidence that certain cetaceans use concussive blasts of sound to disable their prey (makes a "roar" seem pretty lame by comparison). I'm not aware of any terrestrial equivalents ... but I wouldn't be surprised if there were a few around.
Humans have even been known to temporarily disable other Humans with loud noises; I believe the technology goes by the name of "noise flash diversionary device".
In any case, I like the stuff about how digestion strategies contributed to the evolution of mammals, and primates in particular -- if only for anthropocentric reasons.
#103 -- I suspect that the use of a sonic concussion as a weapon is more effective in water, given the greater density of water, the faster speed of sound, and the fact that many marine organisms have densities similar to the surrounding water.
Then we move on to Ediacaran organisms. The evidence shows that they weren't photosynthetic, but were some kind of animal that had to have fed somehow, and probably were passive absorbers of drifting nutrients. They suggest that they were replaced by Cambrian organisms that had guts.
Ah well, at least they recognised the Ediacarans as metazoans, so I suppose that's a small victory, but the rest is wrong.
There's ample evidence for guts is ediacaran organisms, especially Dickinsonia, Parvanchorina, and especially Kimberella. There is also a trace fossil record through the late Ediacaran Period.
They disappear from the fossil record because of the rise in burrowing activity at the start of the Cambrian, which destroyed the taphonomic enviroment that allowed the ediacarans to be preserved, and they probably survived into the Cambrian alongside "Cambrian" organisms. The is fossil evidence for at least one - Swartpuntia - in the Cambrian.
Some forms were probably passive absorbers of nutrients, but others were considerably more 'complex', for example Pambikalbae
Re: #105
Is there a good recent review on Ediacarans?
I think they should have spent much more time covering the microbial digestion. It might not seem interesting, but throw in some awesome CGI (Expelled even had some) and it could be. But when you understand how cells eat, evolution seems all the more probable (like with most life functions). More cells = Better food collection. It also would help to dispell diet myths. Like eating only meat will help you lose weight. There's a reason we like chocolate cake, people!
Alas, I'm sure the average american viewer would have been inordinately freaked out by the revelation that he or she harbors roughly 1 kg of bacteria in his/her gut tract.
1 kg! That's like 12 lbs, right? Ew! :)
1 kg! That's like 12 lbs, right? Ew! :)
2.2 lbs
(Have to keep up my reputation for ruining jokes by doing "the simple math" that everyone else already understood to be part of the joke) :-)