Hope for Darwin?
This is a summary of ideas based on Dr. Behe’s books The Edge of Evolution and Darwin Devolves. Most comments are paraphrased or mixed with quotes.
Life on earth did not come about by chance through random mutation, natural selection and common descent as Charles Darwin proposed.
Common descent suggests that different kinds of modern creatures can trace their lineage back to a common ancestor. This is what people often think of when they hear the word “evolution.” But organisms from widely separated categories—buffalos and buzzards, pigs and petunias, yaks and yeast—would seem to each have a common ancestor. For example, gerbils and giraffes—two mammals—are both thought to be descendants of a single type of creature from the distant past that would resemble them in some fashion.
But how did those ancestors get there in the first place?
“Darwin’s idea of evolution pairs random mutation and natural selection to account for differences between creatures. It tries to answer the pivotal question, ‘What could cause such staggering transformations? How could one kind of ancestral animal develop over time into creatures as different as, say, bats and whales?’”
Natural selection says that the most fit organisms of a species will produce more surviving offspring than the less fit. Thus, the progeny of the more fit would replace the progeny of the less fit, and the stronger, faster, hardier critters would do better in nature than ones that were less fit (weaker, slower, more fragile). However, as Behe notes, natural selection can do nothing except twiddle its thumbs until random mutation appears.
Advances in modern science, unknown to Darwin, has actually shown evidence for common descent. That is, the results of DNA sequencing experiments show that some distantly related organisms share apparently arbitrary features that indicate that they were inherited from a distant common ancestor. Second, “there’s also great evidence that random mutation paired with natural selection can modify life in important ways. Third, however, there is strong evidence that random mutation is extremely limited.”
In Behe’s book Darwin Devolves he notes, as he did in his Edge of Evolution, that “purposeful design was needed to account for life beginning from the very foundation of nature…through the elegant machinery of the cell, at least down to the biological level of class. (See table below.)
“Without all that basic stage setting, I wrote, life at that level could not exist. However, there was also then good evidence that the Darwinian mechanism of evolution by random mutation and natural selection could indeed account at least for the origin of new species, perhaps higher classifications. Somewhere between the levels of species and class, I argued, lay the rough boundary between what chance could account for in life and what required intelligent design—the ‘edge’ of undirected evolution.”
He goes on to say that “Darwinian processes (or for that matter any other non-intelligently planned processes) cannot produce descendants that differ from their ancestor at the level of family or higher.”
Biological Classifications
Level
Domain
Kingdom
Phylum
Class
Order
Family
————————
Genus
Species
The reader who is deeply interested in the topic of Darwinian evolution and intelligent design is encouraged to read both of Behe’s books to get much more detail plus the original Darwin’s Black Box.