posted on Jul, 29 2009 @ 12:22 PM
reply to post by ChemBreather
In point of fact, it's inaccurate to say it lost it's legs. If you look at a whale skeleton you can see bones that use to be legs and now are not.
They are completely internal and have likely been given a handful of other functions since they became vestigial.
They may look different but looks are only skin deep.
There are only three parts to evolution. Mutation, Natural Selection, Speciation.
As for the first, the majority of mutations are completely benign because they occur in the Junk DNA (90% of human DNA) which no longer does anything
(vestigial). The majority of the rest are bad, yet some make is fitter in our environment than others.
Natural selection comes in here and determines the frequency of these genes. The fitter and more adaptable become more common as the populations
Speciation begins to occur when there is so much genetic diversity in a population that individuals at the extremes become no longer genetically
compatible. Slowly over time the population begins to drift genetically to either extremes and eventually both groups become genetically isolated and
you have two knew species. Dogs are going through this now where some breeds can reproduce with others. Donkeys and Horses have already gone through
this and now only produce infertile offspring.