In reading an interesting article in the New York Times (in part because it quotes my colleague Andrew MacDougall), I came upon this statement that caused a bit of a cough.

“There’s no such thing as natural selection,” Ziska confides. He is not, he hastens to explain, a creationist. He is merely pointing out that the original 19th-century view of evolution, the one presented by Charles Darwin and Alfred Wallace, is obsolete. Their model presented evolution as a process taking place in a nature independent of human interference. That is almost never the situation today — even at sea, where less than 4 percent of the oceans remain unaffected by human activity, according to a recent article in the journal Science. This interference with nature has set the stage for the success of a growing category of weeds, one exemplified by cheatgrass: invasive plant species.

Yes, humans have some impact on a great portion of the globe, but this is nonsense for at least three reasons. One, just because humans are involved does not make something "artificial selection" and therefore disqualify it as natural selection, even within the formulation of Darwin and Wallace which drew a distinction . Artificial selection is the intentional breeding of organisms on the basis of some characteristic (e.g., sleek body shape in dogs or high yield in crops). If we dump waste in the ocean and this creates new selective pressures on marine animals, this hardly counts as artificial selection. From the point of view of the organisms involved, it is simply a change in the environment, and natural selection will then operate as usual. (As a matter of fact, I don't consider "artificial" and "natural" selection to be fundamentally distinct processes anyhow — feel free to discuss in the comment section). Two, we may influence environments generally, but there are, as we speak, gazillions of organisms out there struggling for survival and hunting, parasitising, avoiding, mating with, and otherwise interacting with one another independent of human action. Three, natural selection is still occurring both in human populations and indeed within human bodies (among pathogenic agents, for example).

(Hat tip: John Hawks blog)

At The Panda's Thumb, Nick Matzke has a post about abiogenesis (the origin of life from non-life) and evolution. He, PZ, and others argue that abiogenesis is part of evolutionary biology and that it is a cop-out to deflect challenges about it from anti-evolutionists. Allow me a brief summary of my interpretation.

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Question: Do we need evolutionary biology to understand the origin of life?

Answer: Very probably. Early replicators, once they arise, would undergo evolution. Mutation, natural selection, etc., would have been important before cellular life as we understand it appeared. However, there are components to the issue that predate the occurrence of natural selection, which are more properly understood in terms of organic chemistry than biology. The line is not sharp, though, so keeping evolution out of abiogenesis research is unwise.

Evidence: Whether "cells" (membranes with stuff inside) or replicator molecules (e.g., RNA) appeared first, if there was heritable variation and reproduction and survival that differed among them, then selection would have happened.

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Question: Do we need to understand how life arose to understand the subsequent evolution of cellular life?

Answer: No.

Evidence: We have been studying evolution seriously for 150 years and understand quite a bit about how it happens, yet we don't know how life arose.

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So, Nick and others are correct that we should not say that abiogenesis is independent of evolution. However, if they are implying that abiogenesis is part of — more importantly, a crucial part of — evolutionary theory, then I do not agree. The influence is one-way, and this is the opposite of the way anti-evolutionists perceive it. They argue that if we do not know how life started, then evolution is false. In actuality, knowing how life started has nothing to do with studying how life has evolved since the first complex cells appeared. However, understanding how complex cellular life evolves probably tells us something about how life arose because the same processes are relevant whenever there are variable replicating entities.

In my opinion, it remains a valid and useful argument to point out that uncertainty regarding the origin of life is irrelevant to the factual standing of evolution over the past 3.8 billion years.