In order to say that some function is understood, every relevant step in the process must be elucidated. The relevant steps in biological processes occur ultimately at the molecular level, so a satisfactory explanation of a biological phenomenon such as sight, or digestion, or immunity, must include a molecular explanation. It is no longer sufficient, now that the black box of vision has been opened, for an ‘evolutionary explanation’ of that power to invoke only the anatomical structures of whole eyes, as Darwin did in the 19th century and as most popularizers of evolution continue to do today. Anatomy is, quite simply, irrelevant. So is the fossil record. It does not matter whether or not the fossil record is consistent with evolutionary theory, any more than it mattered in physics that Newton’s theory was consistent with everyday experience. The fossil record has nothing to tell us about, say, whether or how the interactions of 11-cis-retinal with rhodopsin, transducin, and phosphodiesterase could have developed step-by-step. Neither do the patterns of biogeography matter, or of population genetics, or the explanations that evolutionary theory has given for rudimentary organs or species abundance.
The point which Professor Behe makes for vision applies equally to macroevolution as a whole. The relevant steps in macroevolutionary processes occur ultimately at the molecular level, so a satisfactory explanation of macroevolution must include a molecular explanation.
If, for some reason, certain macroevolutionary transitions appear to be highly improbable from a chemical standpoint, then that in itself is a good reason to be skeptical of the view that Darwin’s theory of evolution is an all-inclusive theory of biology.
(Why Evolution Is True. 2009. Oxford University Press, Glossary, pp. 268-269).
Macroevolution has also been defined by Professor Jerry Coyne as “large changes in body form or the evolution of one type of plant or animal from another type”
Evolutionary change occurs on different scales: ‘microevolution’ is generally equated with events at or below the species level whereas ‘macroevolution’ is change above the species level, including the formation of species.
In nature, evolution occurs at the molecular level of specific, individual mutations, so it is there we must look to evaluate possible evolutionary paths. Studies with less detail can say very little on the topic.
Behe, Darwins Black Box, pg.38:
Other ages have been unable to answer many questions that interested them. Furthermore, because we can't yet evaluate the question of eye evolution or beetle evolution does not mean we can't evaluate Darwinism's claims for any biological structure. When we descend from the level of a whole animal (such as a beetle) or whole organ (such as an eye) to the molecular level, then in many cases we can make a judgment on evolution because all of the parts of many discrete molecular systems are known.