Evolution and Increased Diversity

Welcome to the fray LucyTheApe.A random event would include mutations, volcanoes, meteors, floods, a change in climate.Seasonal change would not be random.Enjoy.

Neither would floods probably be. Nor volcanoes. Changes in climate aren't random either.

The question about "diversity" is misleading. There was once much more diversity in Perissodactyla then we are observing nowadays. Speking generally the same for all mammalian orders. The question is if evolution has a purpose or not. I say that evolution has a purpose and increasing/decreasing diversity only serves to this purpose.The late Gould wrote once that if Yucatan meteorite hadn't fallen down there would have been Dinosaurus ruling our planet today.I doubt about it. Mammalian family diversity was established before Yucatan meteorite fell down. If it didn't fall the process would go on neverthenless.Maybe the process of origin of maninkind wouldn't have been finished yet in such a case, but it would happen sooner or later anyway.Edited by MartinV, : No reason given.

This statement is true in that there were absolutely mammals hanging out before the end-Cretaceous extinction (regardless of what it did to the non-avian dinosaurs--and despite what you read in books/media...the jury is still out on that one). But the statement ignores the fact that non-avian dinosaurs solidly held sway over the vast majority of terrestrial niches at in the latest Maastrichtian. Gould might well have been wrong about modern dinosaur dominance in the absence of an end-Cretaceous whacking of the dinosaurs, but we can do little more fantasize about what mammalian diversity would look like today if the end-Cretaceous extinction had not occurred.

Hot damn! You're starting to make some sense and have a point. Thank you.That part of evolution is included in the ToE under the sections on natural selection. The environment is what drives changes in diversity, not something inherant to the process of evolving. If the environment is favorable, diversity increases, if it is unfavorable, diversity decreases. Random mutation and selective factor that are not associated with the environment, will not necessarily lead to an increase in diversity and can actually have a decrease. It the effects of the environment that effect the diversity. I'm sorry but its hard when you say things like this: How many times to I have to tell you that I don't think that bidiversity has not increased!?

quote:

---

But the statement ignores the fact that non-avian dinosaurs solidly held sway over the vast majority of terrestrial niches at in the latest Maastrichtian.

---

These "niches" are very confounded. I don't believe that niches play any role in evolution. There has been already discussion here about whales. I would say ancestors of whales lived in the same niches as crocodiles did at the same time (-and now). Because Ambulocetus look like crocodile they obviously compete in the same niche untill Ambulocetus became a whale. Using this example I would like to stress the concept that evolution is pre-programmed process that happened regardles of empty or full niches.The same for mammals. Obviously dinosaurs didn't solidly held sway if they didn't eradicate them. There is no ground to believe that dinosaurus would't gave way to mammals once.Mammalian species were once much more diverse than today. I doubt it was due more empty niches in the distant past.

Could you define what you measn by "after evolution." Was there ever a time on Earth that occurred "after evolution"? What else besides biological evolution, which necessarily involves the environment, could account for biodiversity? Don't understand, RADZ. Are you saying that biodiversity has not occurred on Mars because there was never any life there? I'd have to agree to that! The only thing I can gather from what you are saying is that life alone does not account biological evolution. Well, I can agree to that, because life doesn't exist in a vaccuum.”HM

Isn't that like saying the color of your new car is the result of your choice in the showroom and not the result of the pigmentanation in its paint? I'm gonna strain my brain to get this, Catholic. Are you saying that only environmental factors independednt from biological evolution can account for biodiversity?”HM

Before there was life on Earth there was no evolution. After life emerged and began evolving, is the time "after evolution".Now, some time after that, there was an increase in biodiversity and also Pangea expanded.To say that Pangea expanded because species were evolving is an application of the Post Hoc Ergo Propter Hoc fallacy.There is no reason to think that evolution caused Pangea to expand other than one occured after the other.It is the same with the increase in biodversity. You have documented that it has, in fact, increased, but you have failed to tie the cause to the evolutionary process.Thus the fallacy.The increase in biodiversity is a result of changes in the environment, which also effect evolution. But the process inherant to evolving does not necessarily cause the increase. It is capable, but it isn't necessary.The point about Mars is that there was once life on Mars and now there is none (the ultimate decrease in biodiversity). The process of evolving is the same on Mars as it is on Earth. Mars is an example of how evolution can lead to a decrease in biodiversity, because of thenvironment.

No. I don't see it. How so?Environmental factors drive the increase in biodiversity. Species can evolve independent of environmental factors. Therefore, evolution does not necessarily lead to an increase in biodiversity. No.I'm saying that the evolutionary factors that are indpendent of the environment are capable of decreasing biodiversity. (Even the ones that are dependent on the environment are capable too.)

Martin, question: Would you say the overall increase of biodiversity in Sepkoski's graph shown below is or is not associated with of biological evolution? I can agree that an increase in biodiversity is NOT the automatic outcome of biological evolution. We have plenty of evidence on lesser timescales supporting that claim. But I am saying that on a macroscopic timeframe since the Permian Extinction biological evolution has produced a overall increase in biodiversity. No!”HM

I agree”when lesser timescales are inviolved. And I already have said so. Do you think the macro timescale represented in Sepkoski's graph has any bearing on this issue?”HM

Let me answer too. Yes, the overall increase is associated with biological evolution. Evolution can use the environment for selective pressure to drive the evolution to either an increase or decrease in biodiversity. Holy Shitballs! That's my whole point. That's what I'm trying to get you to understand.It looks like you get it. Correct. And that is due to a favorable environment, not because evolution must lead to an increase in biodiversity.Got it?

Under the right conditions, the timescale is irrelevant. If the environment was favorable for a decrease in biodiversity over very long periods of time, then on the macro timescle, biodiversity would decrease. Yes, it shows that the environment has been favorable to an increase in biodiversity.

Forgive me for being a bit obtuse here, but this is just a hypothetical example to illustrate the fallacy, right?