However, selective breeding of pigeons, chickens, turkeys, cattle, horses, dogs, cats and many other domestic animals yields similar results over less time. Later, the theory says, chance resulted in complex invertebrates and plants, followed by fish, then amphibians, reptiles, and, finally, mammals. The trick is to show how each link could be viable enough for the next to get going. If such transitions ever happened, intermediate forms should be found in the fossils and in living organisms. Existing classes should overlap.
Clear boundaries ought to be exceptional rather than normative.
Though Darwin hoped fossil transitions would appear eventually, none did. Only trivial cases of micro-evolution, hardly rivaling selective breeding, were evident. Nor for more than a hundred years would any accurate measure of distances between existing classes become possible. Or, take the Coelacanth. On the basis of fossil evidence, evolutionists believed it was an intermediate between fish and amphibia.