Expert: John Shea - 1/25/2008

Question
I recently had a debate with another girl over evolution. She gave some rude remarks and told me to read up on some anthropology. Our debate was over the biological evolution of humans. Sure humans could continue to evolve on a smaller scale such as wisdom teeth going away completely. Is it possible that we are already evolving on a large scale? We control most aspects of our environment which makes evolution unlikely to happen. Can this control actually be causing many minor changes among the human population? When all these small changes are looked upon as a whole is this biological evolution? (We excluded third world countries from our debate and focused on only developed countries since they can not as easily control all aspects of their environment). Does evolution have to be on a large scale? Populations can consist of small groups such as a singular family tree? Thank you for you help and clarification :)

Answer
Jon
We are still evolving. As long as you have differences in reproduction (some people have a lot, others fewer or none) you are going to have evolution.
Evolutionary change is slow among large populations of big mammals who reproduce slowly (like humans).  So most of the evolutionary change you would see in recent times is related to minor molecular changes (lactose tolerance, color vision, maybe some cognitive disorders).  Because wealthy people in industrialized societies are well-insulated from a lot of selective forces (predators, pathogens) evolutionary change is really a lot more about relaxing selective pressure and increasing variability.  So, for example, there is probably a lot more variation in eyesight nowadays than there was when humans with poor eyesight either starved or became lion food.
For microevolution in western industrial societies -best example of which I can think involves an apparent genetic resistance to HIV that has evolved among some people of NW European descent.  Unless there is a cure for HIV, then these people have a very favorable genetic mutation and may reasonably be expected to spread throughout the species in our evolutionary future.
I hope this helps.  Best reference -Ernst Mayr's book, What is Evolution.
Cheers
John Shea