Evolution Requires Reduction in Genetic Diversity

One cannot get a pure bred line of dog and maintain diversity ... this is true. If you keep breeding for a specific trait, you will eventually destroy the genetic line through inevitable inbreeding.
But you also cannot equate evolution with the breeding of dogs for specific traits. Although it shows how selection proves evolution, it's not how things happen in the "real world".
Selective breeding of dogs or other domestic animals is not "survival of the fittest". It is unnatural selection of traits desired by the owners. Most modern dogs would not survive in the wild, and would not be able to pass on their genes.Evolution DOES cause diversity, due to the environmental conditions that cause different survival traits to surface and be passed on. Only when on group evolves too far to "mingle" with other offshoots of teh parent species does a "new" species develop.

Okay, maybe I am out of my depth. I am not a genetic scientist. So, the following flight of thought is based on what I've read and how I processed it.
A parent gives it's offspring a genetic advantage, and that offspring becomes a parent. It produces offspring of it's own that strengthen the trait. which continues until a new genetic advantage arises. However, the offspring have separated and there are now several offspring spread over a greater area. The genetic advantages given to successive generations will differ from one area to the next, creating greater variation. The more variation in environment, the more variation will arise in genetic advantage.
Generations later, offspring cross paths. If they have not genetically changed enough, they will still be able to breed, refreshing the gene pool. If they've changed too much, they are now separate and "new" species that cannot breed across the genetic gap.
If you continue to expand this ... genetic diversity grows, it doesn't shrink.Where does this logic fail?

"Where does the genetic advantage come from?"
There is a new "mutation" in each and every offspring. When two parents genes combine into a new creature, that creature is different than either parent.
Say the parents had strayed from the group and were now in an area that had more cliffs and mountainous terrain. This particular offspring just happens to have better foot pads than the parents, and can avoid dangers, find food, impress new mates better. This offspring transmits it's foot pads to more offspring, strengthening the trait. Only those who have the more appropriate foot pads continue the species. True, there might be some genetic inbreeding, while the group is isolated, but it need not continue to failure.As long as this group interacts with another before they get too divergent, the overall species will inherit the foot pads over time. Genetic diversity grows.The Earth is large enough to allow both isolation and reintegration with no problems.

Should I have said, "Now I see YOUR confusion?" ToE doesn't appear to be a fantasy to me.
You are basing your genetic advantage on a "response" to environment. But, it's a change from the parents, only, unless it proves to be an advantage. Every "child" is born with slight "mutations" from the parent, not all of which are advantages. Those mutations which are advantageous live on. Maybe the ones who ended up in the mountainous terrain were better suited to it BEFORE they migrated.Your own argument seems to be proof of evolution, since the same DNA is present throughout the biosphere. Your arguments against evolutionary progression are based on a limited number of alleles and genetic stagnation. The limited number though, is in the billions. If each alleles can be responsible for a mutation, then the possible combinations are in the hundreds of trillions. We might be headed for genetic stagnation ... but the Earth will cease to be habitable before we do.

In one way, and one way only, I have to agree that Faith is correct about genetic stagnation and inbreeding. It will cause inferior specimens of the species and obvious loss of mental capabilities. In the wild, these inferior specimens are weeded out by natural selection. In the human population, these inferior specimens end up in government.

Now I am confused, too.
Are you arguing for evolution or against it?
Because it looks like you're agreeing that there is proof of dwindling genetic diversity, which according to your statements proves evolution.

I read this and can't help but think of the insect world. Genetic changes have created such a vast array of insects, many of which are (in many cases) MUCH more complicated than mammals and other vertebrates. A good example is the lightning bug. No mammal has developed bio luminescent capabilities.
But the VAST number of insect species within a family, like the beetles, proves that different species can, and do, arise from parent populations. Not only arise, but thrive, adapt and modify into even more offspring populations that become unrecognizable from the ""grandparent" populations.

You keep speaking of this lack of genetic material, or running out of alleles. But you're dealing with a set of combinations that is virtually limitless. The combination of different genes from two parents give rise to an offspring with a "new" set of genes. It renews the possible alleles combinations. True, some carry on, those that reinforce positive reactions to current environments, but the genome is capable of renewed changes.
Every succeeding generation has as many possibilities for change as the parents did ... diversity continues.

As long as that group of people are confined to that island, you are correct. BUT ... if the rest of the world's population was wiped out, and the islanders got off the island, they would repopulate the Earth. And those that repopulate the tropical regions will evolve differently than those that repopulate the other parts of the world. In a few generations, they will look differently. After a few more generations, the Earth's population might look much as it does today.AND ... if some of the original islanders stayed on the island and refused to mingle with the rest of the world, they might eventually be unable to breed with anyone except other islanders and two species of humans will exist. Homo-Islandus and Homo-therestofus.

You keep asking this. Genetic change in inevitable when half each of two parents' genes make the genes of the offspring. The changes that benefit the offspring in the drive to reproduce are carried on. The changes that inhibit reproduction aren't.
The genetic changes aren't a response to the environment, the environment weeds out unproductive changes.

Alleles are not a one time and done code. Basically, they are on/off switches. This means that any set of alleles can be switched on or off, and any group of alleles have several combinations based on which ones are on and which ones are off.
Just as an example, use computer code: (from inet2000.com) There are billions of genes. The number of alleles combinations is almost infinite. The fact that the parents only give HALF of their DNA to the offspring refreshes the alleles possibilities. There is no "dead end" because the "system" is:
1) Partially reset in each generation.
2) Virtually infinite even if it didn't reset.

ToE does not happen over night. You use the Cheetah as an example. It evolved to chase down prey that was too fast for other cats. Thus putting in a survival niche that allowed it's continued survival. This took tens of thousands of years. They face extinction now because the environmental changes are happening too fast for genetic changes to prove beneficial or not.
ToE is exactly why some "bodies" do survive.

From an earlier post: And: YES, yes, yes !!!
The adaptation is NOT a response to the environment. It is an accidental perturbation in the "new" genes of the offspring. But the first cat that had extra speed was able to bring down available game by itself better than the previous generation and "impressed" a mate and reproduced. This happened again and again through many generations. What we see now is just the "newest model" of the Cheetah line. Slimmer, faster cats were just more capable and reproduced.Genetic adaptation IS an accident. It's NOT a "choice". If that "accident" is beneficial, it propagates through successive generations because it HELPS reproduction.
Nothing in this process though is "irreversible" and does not lead to genetic dead ends. Edited by mikechell, : No reason given.

Thank you for the correction, although it was unnecessary. The number I posted was directly quoted off the site I was on ... I just deleted the math in between.My point was that only 128 variables of on/off allow for almost unimaginable number of variations. The proportional increase of variations based on the gene and alleles numbers is virtually infinite. Even if each genetic change that led to a new species was permanent (which it isn't), there is infinitesimal diminishing of the possibility of future changes within the lifespan of planet Earth.But you pointed out that your correction wasn't about the point I was trying to make. I just realized that ... but I am too lazy to erase what I typed in above.Edited by mikechell, : lack of earlier observation.

I wrote this a few posts back ... doesn't get much simpler than this.