QUOTE : All this refers to one aspect only of the evolution of reptiles; needless to say, countless other essential transformations of structure and behaviour were required to make the new creatures viable. The changes could have been gradual-but at each step, however small, all the factors involved in the story had to cooperate harmoniously. The liquid store in the egg makes no sense without the shell. The shell would be useless, in fact murderous, without the allantois and without the tin-opener. Each change, taken in isolation, would be harmful, and work against survival. You cannot have a mutation A occurring alone, preserve it by natural selection, and then wait a few thousand or million years until mutation B joins it, and so on, to C and D. Each mutation occurring alone would be wiped out before it could be combined with the others. They are all interdependent. The doctrine that their coming together was due to a series of blind coincidences is an affront not only to commonsense but to the basic principles of scientific explanation.