explaining common ancestry

1)How the "common ancestor" got the traits of a human?The answer is simple, it didn't, or at least it is very unlikely that the latest common ancestor of chimps and humans had any particularly unique and characteristic human traits. The point of a common ancestor is not to be a 'missing link', i.e. supposedly half human and half chimp, but rather to be an animal which has all of the features which are common to both humans and chimps, and ideally for the best resolve features common to those two groups alone.So the 'Common ancestor' would not have uniquely human traits, they would be hypothesised to have arisen in the intervening generations as the 'common ancestral' species diverged into 2 distinct human and chimp lineages as seen from this point in time.2) As to how these traits arose during the evolution of the human lineage; The answer has to be the obvious one of mutation and natural selection. Most of the traits which distinguish us from chimps are highly complex polygenic traits the gconstituent genetic components of which are phenomenally hard to unravel.The are some suggestive studies on things such as speech where the gene Foxp2 has been shown to affect the neurological deveopment of systems involved in speech and language (Vargha-Khadem , et al., 2005). Many of the differences we consider most important are likely to be cognitive, the merely morphological differences may be a lot easier to pin down in the long run.TTFN,WK

Not careful enough mein freund, there are a number of animal species whose origins are posited to be rooted in hybridisation and ploidy. Members of the family Pipidae, especially many species of , being a prime example.TTFN,WK

They don't know this, mostly because it is utter rubbish. Given that, as you correctly note, different species cannot breed with each other there can clearly be no such cross-species hybridisation.Of course there are some things that we identify as different species, or even higher taxonomic orders, which can yet produce offspring. But this is to do more with the fact that our grouping of organisms into species has not been traditionally based on testing their interfertility. This never has and never will be the proposed mechanism of human evolution. Do you have a single scrap of evidence to support the idea that it has?TTFN,WK

Ape is not a species. There are many different species in the apes. We can't interbreed with other extant modern species of apes because of genetic/physiological incompatibilities.TTFN,WK