The book Darwin Devolves

[shunyadragon]

So evolution would tend to get stuck, even if selective pressure was reversed, it would be difficult for the mutations to reverse.

Source: Darwin Devolves

If they are right, as there is every reason to think, the results throttle Darwinian evolution even further.

© Copyright Original Source

Blessings,
Lee

This total nonsense. Evolution does not rely on mutations in reverse. Again Behe nonsense not meaningful to the science of evolution.

[Roy]

So evolution would tend to get stuck, even if selective pressure was reversed, it would be difficult for the mutations to reverse.

Source: Darwin Devolves

If they are right, as there is every reason to think, the results throttle Darwinian evolution even further.

© Copyright Original Source

Evolution doesn't require that mutations reverse.

[rogue06]

Evolution doesn't require that mutations reverse.

I really have to wonder just where Lee, and Behe, come up with this stuff. It is total nonsense.

[shunyadragon]

In the book Darwin Devolves, Behe mentions work by Thornton that states that evolution doesn't seem to have a reverse:

Source: Thornton

Whether evolution can go back to an ancestral structure just by reversing the selection pressure on function has been a long-standing issue, but one hard to address based on just the history of forms. Bridgham et al. have now physically reconstituted ancient versions of a regulatory protein ... They find that amino acids that were essential in an ancestral protein become neutral in a more recent form, where they are then subject to erosion by genetic drift. This loss deprives natural selection of the necessary raw material with which to reverse the historical substitutions — they are no longer 'adaptive' as they were in the other direction. Evolutionarily speaking, there is no turning back.

Source

© Copyright Original Source

Behe writes:

Source: Darwin Devolves

In fact, they predict that further work “will support a molecular version of Dollo’s Law.” That is, “as evolution proceeds, shifts in protein structure-function relations become increasingly difficult to reverse.” If they are right, as there is every reason to think, the results throttle Darwinian evolution even further.

© Copyright Original Source

Blessings,
Lee

You need to describe specifically why evolution why evolution would require reverse mutations.

[lee_merrill]

Evolution doesn't require that mutations reverse.

You need to describe specifically why evolution why evolution would require reverse mutations.

No it doesn't, but if evolution goes down a path of deleterious mutations, it would then be difficult to reverse those, even if selective pressure is reversed.

Blessings,
Lee

[Roy]

No it doesn't, but if evolution goes down a path of deleterious mutations, it would then be difficult to reverse those, even if selective pressure is reversed.

SO WHAT?

If evolution goes down a path of neutral or beneficial mutations that later prove to be deleterious due to environmental shifts, it still isn't necessary to reverse those mutations. Are you not aware that other mutations may arise that compensate, as has been explained to you multiple times by TheLurch in this very thread? Are you not even aware that species that cannot adapt to changing environments fast enough go extinct?

Once again you show no sign of knowing anything at all about evolution, not even what you could have learnt last week.

Your ignorance is not an argument.

[shunyadragon]

No it doesn't, but if evolution goes down a path of deleterious mutations, it would then be difficult to reverse those, even if selective pressure is reversed.

Blessings,
Lee

Deleterious mutations simply cause organisms to fail to compete, organism dies or fails to reproduce. You know survival of the fittest, or thinning the herd eliminating those not able to compete. There is no need for reverse mutations. Again this line of reasoning simply fails to be meaningful concerning the science of evolution.

Deleterious mutations do not effect the survival of the species, nor evolution, unless, of course, there is a nuclear war, or the sun goes nuclear.

[lee_merrill]

If evolution goes down a path of neutral or beneficial mutations that later prove to be deleterious due to environmental shifts, it still isn't necessary to reverse those mutations. Are you not aware that other mutations may arise that compensate...

Certainly, but the most direct path back to a previous state is to reverse the mutations. That would seem to be easy, but the paper states that this would be difficult.

Blessings,
Lee

[lee_merrill]

Deleterious mutations simply cause organisms to fail to compete, organism dies or fails to reproduce. You know survival of the fittest, or thinning the herd eliminating those not able to compete. There is no need for reverse mutations.

But if selective pressure is reversed, should we expect to see evolution travel in that direction? The surprising answer is, no.

Blessings,
Lee

[shunyadragon]

But if selective pressure is reversed, should we expect to see evolution travel in that direction? The surprising answer is, no.

Blessings,
Lee

The not so surprising answer is none of the above. Selective pressure does not reverse mutation. In fact reverse mutations do not likely exist at all. Natural Genetic drift provides the genetic diversity for evolution. Selective pressure based on changes in the environment and adaptation to new environments. Based on observation of the different ecosystems of our world, the more naturally abundant environments such as tropical rain forests, and shallow temperate to tropical seas have the greatest genetic diversity and the fertile ground for the future evolution of species.

Again, deleterious mutations are dead ends, and lead to the failure of individuals to survive and reproduce, and do not contribute to the evolution of species.




































































just selectively acts on the genetic diversity of the population of the species available at the time.

[rogue06]

No it doesn't, but if evolution goes down a path of deleterious mutations, it would then be difficult to reverse those, even if selective pressure is reversed.

Blessings,
Lee

Why do you think that it would even take such a path when selective pressure would weed them out?

[shunyadragon]

Certainly, but the most direct path back to a previous state is to reverse the mutations. That would seem to be easy, but the paper states that this would be difficult.

Blessings,
Lee

Not just difficult, most likely impossible, because the individuals with deleterious mutations would not survive.

[lee_merrill]

Why do you think that it would even take such a path when selective pressure would weed them out?

Not just difficult, most likely impossible, because the individuals with deleterious mutations would not survive.

Sorry, I should have said mutations which degrade or disable a gene, but which provide a selective advantage.

Blessings,
Lee

[HMS_Beagle]

Sorry, I should have said mutations which degrade or disable a gene, but which provide a selective advantage.

Those are called beneficial mutations, just so you know, and they tend to accumulate.

[Roy]

Certainly, but the most direct path back to a previous state is to reverse the mutations. That would seem to be easy, but the paper states that this would be difficult.

Again, SO WHAT? Evolution doesn't require a return to a previous state.