Neb - question......

[Guest HIS girl]

I was watching an animal show the other night and they said that the cheetah was the most ancient of the big cats having survived and thrived for the last 3 million years....

in terms of evolution...wouldn't there be changes in that time frame?

I know you are a Creationist (as am I) but I am asking you since you are the smartest gal on the block here!!!!!

[nebula]

Hey -

I'm not an expert on this, but I'll share what I do know.

Fossil remains of cheetahs have been found in North America. It makes sense that they used to be here because we have antelope which are designed for escaping a fast predator, which we do not have here. (Yes, we have wolves, but their running ability is endurance rather than speed - relatively speaking.)

The cheetahs we have now are genetic equals, as if they were identical twins. For reasons unknown, there must have been what is called a "bottleneck", where all but a few of the species died. The remaining cheetahs managed to breed enough to save the population, but there were too few to keep the genetic diversity (remember learning about genotypes and phenotypes with Punnit Squares?).

So that right there prevents any more changes to occur, even on a small scale.

Unless a one of those infamous beneficial mutations occur which supposedly drive evolution along....

[Guest HIS girl]

Hey -

I'm not an expert on this, but I'll share what I do know.

Fossil remains of cheetahs have been found in North America. It makes sense that they used to be here because we have antelope which are designed for escaping a fast predator, which we do not have here. (Yes, we have wolves, but their running ability is endurance rather than speed - relatively speaking.)

The cheetahs we have now are genetic equals, as if they were identical twins. For reasons unknown, there must have been what is called a "bottleneck", where all but a few of the species died. The remaining cheetahs managed to breed enough to save the population, but there were too few to keep the genetic diversity (remember learning about genotypes and phenotypes with Punnit Squares?).

So that right there prevents any more changes to occur, even on a small scale.

Unless a one of those infamous beneficial mutations occur which supposedly drive evolution along....

Cheetah fossils in N Am? Wow, never heard of that before...

and no I don't remember the term Punnit Squares!!

Was the decline of cheetahs in Nth Am before or after the great African animal shows in ancient Rome in the Colleseum? I know from that alone, some species of African animals were nearly decimated to the point of extinction...just wondering if there was trading going on in Nthe Am at that time for cheetahs....I only put this forth because of what I have heard about trading between Australian Aborigines and Ancient Egyptians, that ancient folk DID get around for trade purposes etc...maybe the American Indians did trade with Romans for cheetahs...hence the decline in Nth Am.?.....who knows?

[nebula]

http://en.wikipedia.org/wiki/Punnett_square

I really don't know, HG.

Scientists date the NA fossils to 100,000 years ago. So ????

[Guest HIS girl]

Oh my goodness!!

I need a brain re-charge..... Native American Indians trading cheetahs?? Um...recheck...how bout ancient Romans just taking the cheetahs free of charge.........................!

[Fez]

Cheetahs survived because they could run faster than "evolution"

Tortoises did because they pulled their heads in and waited for it to go away......

Crocodiles did because they are too mean to accept any change.....

Next time don't ask Neb, ask an expert

[Guest HIS girl]

Cheetahs survived because they could run faster than "evolution"

Tortoises did because they pulled their heads in and waited for it to go away......

Crocodiles did because they are too mean to accept any change.....

Next time don't ask Neb, ask an expert

Einstein, eat your heart out.....!

[MorningGlory]

Cheetahs survived because they could run faster than "evolution"

Tortoises did because they pulled their heads in and waited for it to go away......

Crocodiles did because they are too mean to accept any change.....

Next time don't ask Neb, ask an expert

Einstein, eat your heart out.....!

[nebula]

So that right there prevents any more changes to occur, even on a small scale.

Unless a one of those infamous beneficial mutations occur which supposedly drive evolution along....

Just wondering what the evolutionists think of this?

[nebula]

It is actually very hard, if not impossible in both lab and nature, to go even a single generation without change let alone 3 million years. Each time a cell divides it accumulates mutations; each human zygote has on average about 120 mutations at conception that neither parent had.

So why are cheetahs considered to have the genetics of identical twins? Would not we see even ever so slight changes by now?

In environments that don't change radically or if a particular organism finds a niche that works really well, there is very little selective pressure to change in ways that would look big to us. I don't know if that is what happened with the cheetah, but it is a possibility.

If the environment changed radically, would not the genetic change also have to respond rapidly? If evolution takes thousands to millions of years to change an organism, would not the radically changed environment have an adverse affect on them before they had the chance to adapt?

In reality, small populations can evolve faster. We normally associate mutations with evolution, and while they are the most consistent factor over long periods of time, the biggest factor is gene flow. And the smaller the population the faster gene flow can spread throughout the population (founder effect).

Well, the population can't get any smaller than where the cheetahs are at genetically.

There's evidence that the cheetah had two bottlenecks, the last one being very recent within the last thousand years. So the low genetic diversity may just be from a very recent bottleneck.

That's what I said (except for the two bottleneck parts.)

P.S. Beneficial mutations aren't the only factors that drive evolution. Mutations in general drive evolution along with a host of other factors from the environment.

If change is a result of the environment, would that not more appropriately be called "adaptation" rather than "evolution"?