While not germane to most of the subject matter here, the following, from the recent special SCIAM on Evolution and the Rise of Intelligence, struck me as particularly poignant description of evolutionary process. Since many of my readers get here by way of the IIDB, they may appreciate it.
"When we contemplate the extraordinary abilities and accomplishments of Homo sapiens, it is certainly hard to avoid a first impression that there must somehow have been an element of inevitability in the process by which we came to be what we are. The product, it's easy to conclude, is so magnificient that it must stand as the ultimate expression of a lengthy and gradual process of amelioration and enhancement. How could we have got this way by accident?. . .Yet that seems not to be how evolution works; for natural selection is not--it cannot be--in itself a creative process. . .Evolution is best described as opportunistic, simply exploiting or rejecting possibilities as and when they arise, and in turn, the same possibility may be favorable or unfavorable, depending on environmental circumstances (in the broadest definition) at any given moment. There is nothing inherently directional or inevitable about this process. . ."(Ian Tattersall, How We Came to be Human)