Evolution worsk like, argh, i can write a 4 page essay on the topic, ill link some youtubes that are better to explain on the bottom of the post....

And evolution does not need two genders, there are lots of life forms on planet earth that can mate with them selfs or replicate without mating and other mechanisms.

The reason our evolution has lead to two genders is pretty simple, what our genes are made up of "wants" to be replicated, and like a current taking the less resistive path our genes "wants" to have a host that is best suited for making more copies (and replicating). With two genders you get a nice mix of different genes (junk DNA and otherwise, but dont be alarmed of the name junk DNA its actually quite usefull) which with natural selection is a really really practical way of trying to make sure you (as in the gene) gets replicated more.

The reason biological compounds works like this is that those biological compounds were the only once that were interested in surviving.

this playlist contains also how evolution works, but i recommend just watching the whole thing, cos YOU are going to learn lots of stuff you might like
http://www.youtube.com/user/potholer...23537556D7AADB