Here’s a key excerpt from an interview with Lynn Margulis
Francisco Ayala is presenting at the “evolutionary mechanisms session” in Rome. He was trained in Catholicism, Spanish-style, as a Dominican. We were in California at a meeting with Whiteheadian philosopher John Cobb. At that meeting Ayala agreed with me when I stated that this doctrinaire neo-Darwinism is dead. He was a practitioner of neo-Darwinism but advances in molecular genetics, evolution, ecology, biochemistry, and other news had led him to agree that neo-Darwinism’s now dead.
The components of evolution (I don’t think any scientist disagrees) that exist because there’s so much data for them are: (1) the tendency for exponential growth of all populations — that is growth beyond a finite world; and (2) since the environment can’t sustain them, there’s an elimination process of natural selection.
The point of contention in science is here:
(3) Where does novelty that’s heritable come from? What is the source of evolutionary innovation? Especially positive inherited innovation, where does it come from?
It is here that the neo-Darwinist knee-jerk reaction kicks in. “By random mutations that accumulate so much that you have a new lineage.” This final contention, their mistake in my view, is really the basis of nearly all our disagreement.
Everybody agrees: Heritable variation exists, it can be measured. Everybody agrees, as Darwin said, it’s heritable variation “that’s important to us” because variation is inherited. Everyone agrees “descent with modification” can be demonstrated. And furthermore, because of molecular biology, everybody agrees that all life on Earth today is related through common ancestry, as Darwin showed.
Everybody agrees with ultimate common ancestry of Earth’s life, because the DNA, RNA messenger, transfer RNA, membrane-bounded cell constituents (lipids, the phospholipids) that we share – they’re all virtually identical in all life today, it’s all one single lineage. So that part of Darwinism – that we’re all related by common ancestry –no scientist disagrees with.
The real disagreement about what the neo-Darwinists tout, for which there’s very little evidence, if any, is that random mutations accumulate and when they accumulate enough, new species originate. The source of purposeful inherited novelty in evolution, the underlying reason the new species appear, is not random mutation rather it is symbiogenesis, the acquisition of foreign genomes.