On the Origin of Feces

[Kai]

We actually have a little bit of recent evidence of current evolution happening:

http://news.nationalgeographic.com/news/2006/07/060714-evolution.html

http://www.pbs.org/wgbh/evolution/library/01/6/l_016_01.html

This gets picked at by the creationists, due to it not being a 'radical' enough change.

That study is really interesting because it validates catastrophic evolution, where extreme pressures cause evolution to occur very rapidly. I've always thought there was a lot of potential in that theory.

I tend to hold with Gould's ideas that evolution is neither completely gradual nor completely catastrophic; evolution is a punctuated equilibrium.

I like that phrase, and yes, it makes perfect sense that it would be. Gradual change punctuated by fits, starts, and dead-ends.

[Shibboleet The Annihilator]

Disappointment Ahead: This is not actually about poop.

I believe Evolution is true. But... I have a question.

Say there's a dinosaur. And millions of years later, his descendants are birds. Okay, fair enough. I can understand why a species might evolve the ability of flight. But why start down that path if it takes millions of years to get there? What practical advantage is a dinosaur with a few sparse feathers? What advantage in natural selection does an animal have that, for example, has evolved feathers but not flight? Do its genes just say "well, that's okay, we're going for flight and we'll get there eventually, for now all we have are feathers..." ?

Evolution is purposeless. There are no goals. There are traits that allow a species to survive and pass on their genes.

The trait may be very stupid. Take something like sexual selection. For example: female birds think a male bird with plumage that is so ridiculous that it actually makes them more vulnerable to predators are more attractive, so the entire species begins to take that trait on. Evolution is does not have an end-game or design. If you're really interested in learning more about this, check out The Blind Watchmaker by Richard Dawkins.

Yes, I realize someone may have already answered this. No, I don't care.

[Kai]

Disappointment Ahead: This is not actually about poop.

I believe Evolution is true. But... I have a question.

Say there's a dinosaur. And millions of years later, his descendants are birds. Okay, fair enough. I can understand why a species might evolve the ability of flight. But why start down that path if it takes millions of years to get there? What practical advantage is a dinosaur with a few sparse feathers? What advantage in natural selection does an animal have that, for example, has evolved feathers but not flight? Do its genes just say "well, that's okay, we're going for flight and we'll get there eventually, for now all we have are feathers..." ?

Evolution is purposeless. There are no goals. There are traits that allow a species to survive and pass on their genes.

The trait may be very stupid. Take something like sexual selection. For example: female birds think a male bird with plumage that is so ridiculous that it actually makes them more vulnerable to predators are more attractive, so the entire species begins to take that trait on. Evolution is does not have an end-game or design. If you're really interested in learning more about this, check out The Blind Watchmaker by Richard Dawkins.

Yes, I realize someone may have already answered this. No, I don't care.


It's not stupid if it works. Take plumage. The obvious plumage makes them more vulnerable to predators, but if the male can survive with that obvious plumage it shows other traits good for avoiding predation.

It's also, as I said already, a matter of adaptation and exaptation.

[tyrannosaurus vex]

Well, after all that, I would just like to say that I find it extremely awesome that birds are actually dinosaurs. I've always thought it was really sad that all the dinosaurs died, but now I know that at least one family of them ended up surviving after all. Sure they're not really the ravenous predators they once were (I guess they're kind of the Russia of evolutionary history that way), and some of them have even become downright cute, but still it's a relief to know that the only class of animal that ever really deserved to exist on this planet isn't completely gone.

[Mesozoic Mister Nigel]

Well, after all that, I would just like to say that I find it extremely awesome that birds are actually dinosaurs. I've always thought it was really sad that all the dinosaurs died, but now I know that at least one family of them ended up surviving after all. Sure they're not really the ravenous predators they once were (I guess they're kind of the Russia of evolutionary history that way), and some of them have even become downright cute, but still it's a relief to know that the only class of animal that ever really deserved to exist on this planet isn't completely gone.

If you've ever had chickens, you might feel differently. Those fuckers will eat anything they can catch. If they had any size on 'em they'd be dangerous as fuck.

[Elder Iptuous]

good thread, Kai!
thx.

[Brotep]

I love that we have people on here with, like, actual expertise in stuff.

[Kai]

Well, after all that, I would just like to say that I find it extremely awesome that birds are actually dinosaurs. I've always thought it was really sad that all the dinosaurs died, but now I know that at least one family of them ended up surviving after all. Sure they're not really the ravenous predators they once were (I guess they're kind of the Russia of evolutionary history that way), and some of them have even become downright cute, but still it's a relief to know that the only class of animal that ever really deserved to exist on this planet isn't completely gone.

Yeah, the class Aves is the last extant lineage of the Theropods, and is sister to a group that includes genera like Utahraptor, Velociraptor, and Deinonychus. Since all the other Theropods are extinct, the closest living relatives of birds are crocodilians. Weird, huh?

[tyrannosaurus vex]

Is there a prevailing hypothesis about whether all modern birds descend from a single therapod, or whether different bird species have lineages that date to different pre-avian dinosaurs?

[Kai]

Is there a prevailing hypothesis about whether all modern birds descend from a single therapod, or whether different bird species have lineages that date to different pre-avian dinosaurs?

Aves seems to be monophyletic, indicating a single common ancestor. There is no evidence to suggest that the group has multiple origins.

[Kai]

Well, after all that, I would just like to say that I find it extremely awesome that birds are actually dinosaurs. I've always thought it was really sad that all the dinosaurs died, but now I know that at least one family of them ended up surviving after all. Sure they're not really the ravenous predators they once were (I guess they're kind of the Russia of evolutionary history that way), and some of them have even become downright cute, but still it's a relief to know that the only class of animal that ever really deserved to exist on this planet isn't completely gone.

If you've ever had chickens, you might feel differently. Those fuckers will eat anything they can catch. If they had any size on 'em they'd be dangerous as fuck.

The only real difference I can see between the earlier Archeopteryx and other basal Avialae is the long tail, and teeth. There are actually some birds still around today that retain the "finger" on the edge of the wing.

Edit: Like the Hoatzin: http://en.wikipedia.org/wiki/Hoatzin

[Elder Iptuous]

Nigel,
there is still hope that we can have chickens with teeth:
http://www.eurekalert.org/pub_releases/2006-02/cp-btm021506.php

[Kai]

It's interesting that, out of all the lineages of Archosaurs that ever existed, only two lineages remain extant, one, aquatic and confined to tropical and subtropical fresh and estuarine waters, the other cosmopolitan, primarily terrestrial, with most species possessing the ability of flight. Strange.

[Doktor Howl]

Crappy world, with crappy "dinosaurs" that don't get any bigger than a bird or a crocodile.

I feel ripped off.

[Kai]

Crappy world, with crappy "dinosaurs" that don't get any bigger than a bird or a crocodile.

I feel ripped off.

Somehow, I don't think a meteor explains this completely.