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Evolution

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MatC
163547.  Fri Apr 06, 2007 4:46 am Reply with quote

Very interesting: so the question could be something like "What changes did Darwin make between the first and second editions of his book on evolution?" The answer: he added evolution to it.

 
Jenny
163603.  Fri Apr 06, 2007 8:29 am Reply with quote

For goodness' sake don't give the bloody creationists any more ammunition!

 
Gray
163611.  Fri Apr 06, 2007 8:43 am Reply with quote

LOL. Don't worry - they don't even have any guns...

 
eggshaped
167153.  Wed Apr 18, 2007 4:33 am Reply with quote

Since humans and chimps branched off the evolutionary tree, chimps have evolved more than humans. At least according to a study in the Proceedings of the National Academy of Sciences.

Quote:
Bakewell, Zhang and a colleague found that substantially more genes in chimps evolved in ways that were beneficial than was the case with human genes.

The results could be due to the fact that over the long term humans have had a smaller effective population size compared with chimps.


linkity link

 
Gray
167185.  Wed Apr 18, 2007 5:22 am Reply with quote

I've been following this quite closely, and most of the reports (retorts) from biologists are complaining that 'more evolved' doesn't really mean anything, other than a nice 'contrary sounding' fact that the media like.

The bottleneck theory is right, though - undoubtedly. We were down to a few hundred thousand at one point, which is why we're all so similar compared to most other mammals. Cheetahs had it far worse: they're all about as closely related to one another as identical twins...

 
Flash
170306.  Sat Apr 28, 2007 3:51 am Reply with quote

What did T-Rex evolve into?

Chickens, apparently. Or perhaps I'm reading too much into this:

Quote:
Scientists from North Carolina State University think they have established the first proper molecular evidence for the hypothesis (that birds are descended from dinosaurs), thanks to the discovery of a small amount of soft tissue preserved in a 68-million-year-old T-rex leg bone unearthed in Montana in 2003. Normally, such tissue is destroyed during the fossilisation process. But in this case scientists were, for the first time, able to extract protein from the remains, and identify it as collagen, a material that gives bone its shape and strength. Further tests revealed the presence of amino acids (protein building-blocks) which, when compared with those of other animals, were found most closely to resemble those in chicken bones.

The Week, 28/4/07

 
Gray
170365.  Sat Apr 28, 2007 9:38 am Reply with quote

T-Rex coudn't have evolved in to chickens because it went extinct, of course.

The DNA comparison shows that they were remarkably similar in certain parts of their genome, though. It's another bit of evidence that shows that birds evolved from what was left of the smaller dinosaur species that didn't get wiped out.

But I bet T-Rex tasted of chicken...

 
Flash
170368.  Sat Apr 28, 2007 9:46 am Reply with quote

It sounded a bit too easy. So they just had a common ancestor, and we know the T-Rex went extinct rather than evolving into something else because it disappears from the fossil record?

 
Jenny
170377.  Sat Apr 28, 2007 10:49 am Reply with quote

Isn't almost everything where the taste is unknown said to 'taste of chicken'? I think this is possibly a tribute to the blandness of factory-farmed chicken.

Incidentally, I can tell you (for I have read it on Conservapedia...) that the young earth creationists are claiming this discovery as evidence that humans and dinosaurs lived at the same time.

 
Gray
170399.  Sat Apr 28, 2007 12:36 pm Reply with quote

Yes, there are no transitional dinosaur fossils whatsoever after 65mya. They were a 'dead end' because they and their food chain were too large to adapt when whatever-it-was-probably-a-meteor made a bit of a mess of the environment.

The little scuttlers did fine, though.

Interesting that the proteins (not the DNA - my mistake) sampled were from collagen on the T-Rex thigh. Must be able to get a good gag out of that.

Here's the breakdown of the analysis:
Quote:
"Out of seven sequences, we had three that matched chicken uniquely and we had another that matched frogs uniquely and another that also matched newt uniquely and a couple of others that matched multiple organisms that include chickens and newts," said John Asara of the Beth Israel Deaconess Medical Centre in Boston, one of the authors of the study.

Dr Asara said the results supported the view that birds evolved from dinosaurs, but added: "If we had more species in the database to compare it to, such as alligator or crocodile, which have not been sequenced yet, we may also find matches to those species. Based on this study, it looks like chickens might be the closest amongst all species that are present in today's genome databases."

http://www.guardian.co.uk/science/story/0,,2056218,00.html

 
eggshaped
170403.  Sat Apr 28, 2007 1:02 pm Reply with quote

IIRC anything which has a similar evolutionary path to chicken tastes of chicken. I read a fascinating paper about this a couple of months ago.

Tarantula tastes of prawns.

 
Flash
170407.  Sat Apr 28, 2007 2:07 pm Reply with quote

But the suggestion does seem to be that "birds evolved from dinosaurs", ie that the dinos didn't so much die out as morph.

 
Gray
170456.  Sun Apr 29, 2007 3:51 am Reply with quote

'Morphing' is just another word for evolution, and that takes millions of years - tens of millions. It's almost certain that birds evolved from 'dinosaurs', but they didn't evolve from the big famous ones like T-Rex.

The archaeopteryx fossil - which appears to be halfway between a small dinosaur and a bird - is about 150 million years old, so that's probably one of the strains that made it by surviving the K-T extinction, and then spent a while evolving into birds. But the other branch was a complete dead end. You can see from this phylogeny what evolved from what. Everything on that tree is now extinct except for the very last twig - Aves.

Paleontology is all very sketchy, because there's not that much to go on. Have a look here for a pretty frank discussion of what we think we know...

 
MatC
170733.  Mon Apr 30, 2007 4:54 am Reply with quote

Jenny wrote:
Isn't almost everything where the taste is unknown said to 'taste of chicken'? I think this is possibly a tribute to the blandness of factory-farmed chicken.


That's an interesting idea. I am just about old enough to remember when chicken was a treat meat, eaten a few times a year, before factory farming made (a version of) it into a daily bread. Was that the 1970s? If so, does the belief that everything unknown tastes of chicken date from around then? I think that whole "tastes of chicken" business would be worth pursuing.

Incidentally, there is a vegetable equivalent: all unknown, forgotten, "wild", and the like, edible plants are invariably "used in place of spinach," according to everything you read. Obscure herbs, edible weeds, that sort of thing - stuff that nobody eats unless they're starving and it's the 17th century - they are always "spinach substitutes." Thing is, I've never met anyone who eats enough spinach to really need back-up supplies.

 
eggshaped
195434.  Fri Jul 27, 2007 8:23 am Reply with quote

Quote:
These talking machines are going to ruin the artistic development of music in this country. When I was a boy...in front of every house in the summer evenings, you would find young people together singing the songs of the day or old songs. Today you hear these infernal machines going night and day. We will not have a vocal chord left. The vocal chord will be eliminated by a process of evolution, as was the tail of man when he came from the ape.


John Phillip Sousa

 

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