Forums → WEPR → Macro-Evolution Vs. Micro-Evolution

Thats a truly interesting question, xxREAGANATORxx. I found myself thinking about this one a bit. While I do believe that species do evolve within themselves based on environmental factors, I cannot completely reject the possibility that, given the right circumstances, (or wrong ones), that a species could form relatives that evolve along a separate line, if only for a while.

When you think about it though, a new speices cannot form, no matter the circumstances. It would require the very genetic code of the organism to be altered. This is impossible, seeing as how natrual selection does not form new genes, but instead, causes them to deteriorate over time.

I understand that position completely. However, how would you explain the obvious diversification of the Galapogos islands, or palentological references to cretaceous species and modern birds?

(oh, and be easy on me...I've been out of college for a few years

First of all, there is no relation between modern birds and dinosaurs. For example, birds have avian lungs. Reptiles have what many refer to as bellow lungs. Obivously, these reptiles would have had to go through a series of changes before they developed such an advanced respitory system such as tha avian lung. But the links between the two would not be able to survive, because their respitory system would not be efficient.

And even if those links could survive with a half and half lung system, natural selection would eventually "weed them out" before they could fully develop into the birds we know today.

ok, so you are a creationist. I'm pretty sure that means that you believe that God basically &quotoofed" everything into existence all at once. Even humans, right? And you also say that you believe that no new species of anything can be formed. So... in that case, there would be dinosaurs running around with humans and other animals that are alive today. How would they be able to survive? Wouldn't natural selection have "weeded" many of today's species out?

noted. However, it seems to me that even though the links may not have a sustained existance, could they not live long enough as a reproductive species to allow for such internal systems to develop? What would the timeline for such a system to develop be, especially if environmental conditions were slow to change?

First off, God created eveything in SIX days. Secondly, dinosaurs were wiped out by a disaster (perhaps a worlwide flood). Thats why they are no longer here. Thats also the reason why there are so many dinosaur fossils.

Well strongbow, thats just the thing. Avian lungs allow a bird to breath in oxygen without having to breath out. The oxygen enters the body and travels through tubes, parabronchi, and out in the opposite direction. Bellow lungs require the organism to breath in and out from the same opening.

There really is no intermediate, and if there was, as soon as it was born, the poor animal would struggle to breath if not at all.

There is a lot of evidence supporting a large-scale extinction of a great many species 65 million years ago, including the dinosaurs. That bieng said, there were quite a lot of species that survived whatever it was that happened, (mammals, for example). The diversity of mammalian species is very extensive. It seems to me that they were certainly not all in existence at the same time. While I certainly can agree that the survivors did indeed diversify within their own chain, I find it very hard to believe that all of the mammals found today are micro-evolved completely from mammalian ancestors.

By the way, there would be no need for a reptile to develop an avian lung in the first place, seeing as how it is no more efficient than the bellow lungs. Its only advantage is at higher altitudes were there is less oxygen. These theropods would have no use for such an adaption, since they never leave the ground.

True. However, that is only one difference between reptiles and birds. Reptiles themselves are intermediates between amphibians and mammals, as well as amphibians and birds. They do share some distinct similarities, while maintaining completely separate branches. I suppose my point is that it is not always a requirement that an intermediate species to go extinct. Fossils dating from the Cretaceous have solid evidence of feathers. Humans have what is left of a tail. All would, in my opinion, be evidence of at least some degree of macro-evolution.

I've got to leave. Nice talking with you, you've got some good ideas.

Oh, by the way, those "feathers" really are not feathers at all. They are really just a parallel array of fibers. They lack the hooks and barbs of the modern bird feather.

LOL. I had a lovely time. And by the way, youre speaking of "modern feathers". Intermediates...remember?

Cheers

@xxREAGANATIORxx: You are flat wrong about the difference between micro- and macro-evolution. One does not support evolution and the other doesn't. They are both forms of evolution; the only difference is the time scale.

As Strongbow pointed out, we have evidence of the intermediates between sauropods and avians. We know one evolved from the other for many reasons, not the least of which is bone structure.

There is so much evidence over so many species and time-frames for evolution, that to claim that it's not what occurs is just ignorant. I strongly think you are incorrect about the difference between avian and saurian lungs (how would you know anyways? the fleshy material doesn't get fossilized anyways). Evolution does not mean that a dino gave birth to a chicken. It means that over many successive generations, a population of creatures adapts to it's environment. Two populations of the same species that live in different areas will be subject to different environmental pressures that can easily cause them to evolve into populations that cannot interbreed. You can easily see this when looking at modern domesticated dogs. They derive from the same wolf-like species, but you trying mating a chihuahua and a great dane and let me know how that works for you.

You also have some problems with genetics here. Reproduction does not "degenerate" genes. Evolution works through genetic mutations. Most of these are harmless, some are harmful and tend to cause the organism with that mutation to die off faster, and others are helpful and allow the organism to reproduce more. These helpful mutations then propagate through the population, causing speciation.

*sigh* I love a smart man!

Thank you kanethebrain. You pointed out exactly what I wanted to say without knowing how to say it!