How have human beings ever evolved?
Yes, humans are still evolving and have not met the
hardy-weinberg equilibrium. Although, I do believe our rate of
evolution has been slowed down. The hardy-weinberg theorem states
that allele frequencies will not chance if there is a large
population, mating opportunities are equal, no mutations occur, no
migration occurs, and no natural selection occurs.
We certainly do have a large population (exception to certain
isolated tribes that have not been influenced). This has slowed
evolution because chance effect of genetic is nullified.
It is arguable to say mating opportunities are not always equal;
we have a hierarchy in society where the rich are clearly separated
from the average and poor. We all have a tendency to mate with each
other. Also, our ability to reason (which seperates us from all
other species) has allowed us to make a much more in depth analysis
into what behavioral and physical traits we are attracted to in our
mates (does not strike me as much different then sexual
dimorphism). This implies sexual selection, which is a form of
natural selection.
Think of all the locations where mutations occur (during
replication, transcription, and translation), it is very
unreasonable to think that in the entire human population no type
of mutation ever occurs. It also has been proven that a mutation
occurs, in a large population, in one in every gamete. Therefore,
microevolution is still occurring.
The human race is obviously always migrating to different
countries, and therefore are under different environmental
pressures. A problem however is that we have gotten extremely good
at altering our environment to our standards rather then adapting.
Furthermore, it has been proven that a gene on chromosome 12 in
Africans has 21 different variations (this is one amongst many
differences in allele frequencies between different races).
Therefore, if a North American, who only has 3 variations, mates
with an African, then the allele frequency has changed and again
the hardy-weinberg conditions are not met.