Evolution

[Chemeyes]

I'm get the survival of the fittest and adapting to changes in environmental conditions etc but I really can't get my head around the development of internal organs and blood vessels etc. What would have driven the development of the liver for example, at one point it wouldn't have been there and then whoosh there it is, it's like there is some kind of consciousness that necessitated the need for those functions? And sexual reproduction, what drove the need to mix up genes and establish variation and then for such a complex system of eggs and sperm and the process of combining them? It all seems too intelligent for the intelligent design corner and far too complex and logical for the evolutionists. is there any evidence showing development of these complex functions?

[Mosaic]

Given the immense amount of time during which evolutionary development has taken place, any number of alternatives could have developed. So the current system of mammalian reproduction is the result of innumerable steps in variation. Bear in mind that mammalian reproduction is only one fraction of all the reproductive systems present in terrestrial organisms. Most organisms don't have a liver but the tetrapods they're descended from had already inherited a digestive system from much earlier organisms. None of how we are now was inevitable - we're just a very very long-term example of how choices made at one point in time affect the future.