Great "why?"s of evolution. We know what happened in evolution - about how cells formed, became eukaryotes. then clumped together, became vertebrates (fish,) amphibians and reptiles, who evolved into mammals and birds. But... why??? What was the point of coming out of water? What caused these events? Why did a nucleus evolve? Why did cells begin to clump together into multicellular life? If an exoskeleton is for protection against predators, why did an endoskeleton evolve? Why did insects evolve? Why did fish crawl out of water? What was the point? Why did reptiles become mammals? If Homo Sapiens killed the Neanderthals, what happened to Homo Erectus, Australopithecus etc? Why did the dinosaurs evolve? Why did the dinosaurs become birds? What caused the Permian extinction a quarter of a billion years ago, which killed 90% of marine life?