Interesting quotes about the probability of macro evolution...
"More muscle is added to the argument by the fact that the vast majority of mutations observed in the laboratory have deleterious effects. This is not at all surprising in view of the digital nature of the genetic code that we shall have occasion to explore in some detail later. After all, one would hardly expect a computer programme to be improved by random changes in its code! Even the tiniest of changes is usually disastrous. But for the moment we simply record that cell biologist E.J. Ambrose of the University of London argued that it is unlikely that fewer than five genes could ever be involved in the formation of even the simplest new structure, previously unknown in the organism. He then points out that only one in 1,000 mutations is non-deleterious, so that the chance of five non-deleterious mutations occurring is 1 in a million billion (1 in 10 to the power of 15) replications. After showing that this is only the beginning of the problems, in having such beneficial mutations integrated into the development of the entire organism and passed on in the gene pool, he concludes 'that recent hypotheses about the origin of species falls to the ground, unless it is accepted that an intensive input of new information is introduced at the time of isolation of the new breeding pair.'" - John Lennox
"As it came clear that the Darwinian theory could not be broadly correct a question still remained, however, for I found it difficult to accept that the theory would be wholly incorrect. When ideas are based on observations, as the Darwinian theory certainly was, it is usual for them to be valid at least within the range of the observations. It is when extrapolations are made outside the range of observations that troubles may arise. So the issue that presented itself was to determine just how far the theory was valid and exactly why beyond a certain point it became invalid." - Fred Hoyle.
I echo these men's questions and struggles with the theory of evolution...(that is, evolution without input from God)