RSR: Spiders & Termites & Magnets

[The Barbarian]

Barbarian asks:
It turns out it works the way Mendel demonstrated that it does. That is part of evolutionary theory. What specific mechanism, required for evolution of new phyla, is ruled out by DNA?

Natural selection.

Show us that. How do you think natural selection is ruled out by DNA?

 

[Yorzhik]

Show us that. How do you think natural selection is ruled out by DNA?

Because most nucleotide changes, even those on their way to creating a new organ, are not selectable.

 

[The Barbarian]

Barbarian suggests:
Show us that. How do you think natural selection is ruled out by DNA?

Because most nucleotide changes, even those on their way to creating a new organ, are not selectable.

Most mutations are neutral. But as you should know, new organs can be made only by favorable mutations, which are open to natural selection. For example, the evolution of a cecal valve in lizards only occurred by mutation when the selective pressures favored it.

The evolution of specific types of hemoglobin (including an "improved" version in which homozygotes do not become fatally ill, while heterozygotes still have protection from malaria) only occurs in areas where malaria is endemic.

So your argument is demonstrably wrong. It's wrong because evolution only uses those mutations that have a selective value. Keep in mind, that over time, neutral mutations can become favorable or unfavorable, as environment or genomes change.

Anything else?

 

[Yorzhik]

Most mutations are neutral. But as you should know, new organs can be made only by favorable mutations, which are open to natural selection.

Yes, I know. That's why it doesn't work. The vast majority of favorable mutations are not open to natural selection.

For example, the evolution of a cecal valve in lizards only occurred by mutation when the selective pressures favored it.

The evolution of specific types of hemoglobin (including an "improved" version in which homozygotes do not become fatally ill, while heterozygotes still have protection from malaria) only occurs in areas where malaria is endemic.

So your argument is demonstrably wrong. It's wrong because evolution only uses those mutations that have a selective value. Keep in mind, that over time, neutral mutations can become favorable or unfavorable, as environment or genomes change.

There is no doubt a few point mutations can be favorable and selectable. But for evolution to work, it needs to be the norm, and it isn't.

 

[Jukia]

But for evolution to work, it needs to be the norm, and it isn't.

So perhaps evolution works but it only has a pert-time job? What is the norm?