[jjw1414]

Yes, Lamarck is alive and well. I frequently hear colleagues in biology with years of experience making lazy statements such as, "Humans evolved to walk because..." as if evolution is a conscious act. In many cases, these people are using the term evolution as shorthand for, "Random mutations gave rise to new gene variants (alleles), and over numerous generations, natural selection leads to an increase in the prevalence of beneficial variants, specifically those that provide a reproductive advantage. The genetic variants that combined to enable bipedal locomotion provided such an advantage to the human population". Evolution is a passive, natural process driven by genetic variation, environmental changes, and the differential reproductive success of individuals with advantageous traits. This in turn results in population changes. Evolution doesn't involve a conscious choice or direction. Evolution is the result of the cumulative effects of these factors over long periods of time.

[dekhn]

While I generally agree with you, is it really "lazy" to say "humans evolved to walk to"? Usually in the context, it's not being used to claim there is some sort of intent or purpose, but rather to shortcut the (rather verbose) description you gave.

Also I can think of some counterpoints to yours: the people who bred teosinte into corn (or any wild grain into a domesticated one) appear to be making conscious choices or direction- that is, they used their intelligence and reasoning from observed examples of pairings to conclude that they could make improved specimens based on selective breeding (without knowing about random mutations of natural selection!).

And if we start to modify human germline then would also be an example of evolution with conscious choice or direction (assuming the modifications became fixed in the population).

[Sharlin]

Even in math, the most exact of all fields of study, people in practice are being nonrigorous and ambiguous and take shortcuts all the time. That’s just how communication works, because it would be incredibly grating and inefficient to try to be 100% unambiguous when everybody already knows what you mean.

[hoseja]

Social, memetic evolution is at least partially Lamarckian.