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Tuesday, February 28, 2012

Exam Question #5

Did you try and answer Exam Question #1, Exam Question #2, Exam Question #3 or Exam Question #4? Were they too hard? Try this one.
Steven Pinker is an evolutionary psychologist at Harvard. He wrote ...
Are we still evolving? Biologically, probably not much. Evolution has no momentum, so we will not turn into the creepy bloat-heads of science fiction. The modern human condition is not conducive to real evolution either. We infest the whole habitable and not-so-habitable earth, migrate at will, and zigzag from lifestyle to lifestyle. This makes us a nebulous, moving target for natural selection.
What definition of evolution do you think he has in mind? Is he correct?


  1. He has only selection as the result of the vicissitudes of the environment in mind, and he's right as far as that is concerned.

    He does not address the fact that the reproductive patterns have changed dramatically in the last century and will continue to do so with increased urbanization, as well as the effects of genetic drift and sexual selection.

  2. I don't know the answer, but I wish I did. Questions like this one make me wish I were an undergraduate biology student. What publication is this quote in? I just started reading Pinker's latest: The Better Angels of Our Nature: Why Violence Has Declined. It is slow going (for me anyway), but I am enjoying reading it and I am learning so much

  3. There is still differential reproductive success, therefore, it is very likely that there is evolution occurring. He seems to be using an adaptationist definition of evolution. But then, he is an evolutionary psychologist...

  4. Like anonymous above said, he likely defines evolution as only selection.
    I am not sure it means anything to say he is correct or not, but evolution is almost universally defined as change in allelic frequency within populations, and using that definition, then ofcourse humans are still evolving.

  5. Species do help to make their environment, and their impact on their environment can have an impact on some selective pressures that would otherwise be more prominent. But there are other species that "infest the whole habitable and not-so-habitable earth,(and) migrate at will". Evolution has not stopped (or slowed) for viruses or bacteria; indeed, the evidence is quite to the contrary.

    Pinker spends an inordinate amount of his time focusing on a relatively small (but important) number of traits that originate from the organ between human ears. Selection may very well play a more prominent role in many central mental/linguistic/creativity traits in humans. But Selection is but one of the routes by which humans evolve. Our lifestyle, and our specific method of global mobility, would not have much impact on other types of evolutionary processes, such as macro-evolution (aren't we increasing a certain type of macro-evolutionary pressure with our culling impact on bio-diversity?) and genetic drift.

    Wouldn't a more global and diverse lifestyle actually increase co-evolutionary pressure, in both a qualitative and quantitative sense? And wouldn't an increase in the diversity of environments to which humans are exposed actually increase, at least at the margins, the selective pressure on some groups of humans?