Rileys Freaky Fridays

Wonderful - I’m in AP Bio and we’re doing this stuff now (in fact, tomorrow I’ve got a test on it.)

Something most people don’t get about the theory of natural selection/evolution is the belief that it is about an individual. The smallest unit of evolution is the population, which may vary in size and genetic differences. So when you think about it that way….

Let’s say that a herd of deer have two alleles for a trait. The recessive version of that trait causes…uh….blindness. So the frequency of the recessive allele, and therefore the appearance of the phenotupe, goes down because the blind deer are usually killed and therefore do not breed.

As natural selection is a measure of an organism’s fitness (the amount of viable offspring it has), it essentially means that the more well adapted an organism is, the more chances it should have to influence the future populations.

So the basic summarization: Natural selection is caused by environmental factors (predators, disease, limited supplies) and therefore affects evolution by “selecting” the individuals best suited for passing on their genetics by surviving.

And as for number two…

As we have little evidence of gradual evolution, we cannot show just how humans evolved from our ancestors. Also, much of our physical adaptations are not advantageous to us (ie, our upright posture - it puts stress on our back and knee joints and causes problems there). An addition to that - the belief that genes are not affected by environment: we did not breed for smaller, duller teeth. Our diet changed and so did we.

I’m not sure exactly how our understanding would be flawed, other than some of the stuff I’ve written already.

Good luck