Is Natural Selection really non-random? (hint: No)
“Natural selection is therefore a result of three processes, as first described by Darwin:
which together result in non-random, unequal survival and reproduction of individuals, which results in changes in the phenotypes present in populations of organisms over time.”- Allan McNeil
Variation, according to the theory of evolution, is random.
Inheritance with sexually reproducing population, is also random.
Fecundity, which individuals will be more fruitful than others, is also random.
Any result depends upon the inputs. And if the three inputs are random the result will also be random.
“Natural selection is the blind watchmaker, blind because it does not see ahead, does not plan consequences, has no purpose in view.” Dawkins in “The Blind Watchmaker”
“Natural selection is the simple result of variation, differential reproduction, and heredity—it is mindless and mechanistic.” UBerkley
“Natural selection is the result of differences in survival and reproduction among individuals of a population that vary in one or more heritable traits.” Page 11 “Biology: Concepts and Applications” Starr fifth edition
To sum it up:
According to the theory of evolution the variation is random. There is no way to predict what variation will show up at any given generation.
Differential reproduction just means that some will out-reproduce others. There is no way to predict what will be selected for at any point in time. We cannot, just by looking at individuals, tell who will out reproduce who. Reproduction is pretty much a crap-shoot.
That is evidenced by the fact not every individual can reproduce- even given a suitable mate. Not every individual, no matter how physically fit, will find a suitable mate- nor any mate.
“Fecundity” just means one is capable of producing offspring, ie fruitful. So one can be the the most physically fit- strongest, fastest, etc., and still not be able to reproduce.
“Natural selection just selects among whatever variations exist in the population. The result is evolution.” (uberk)
And even if an individual from one generation leaves behind more offspring than any one else, that alone is meaningless unless those offspring continue to also out-reproduce those of their generation.
As for heredity, that is not a given either. With sexual reproduction there isn’t any guarantee that the beneficial trait will get passed on. There is also a chance that said beneficial trait could get matched with a deleterious mutation or that what was “beneficial” to one generation is no longer “beneficial”.
Even with all that said what is missed is the following:
Sexuality has brought joy to the world, to the world of the wild beasts, and to the world of flowers, but it has brought an end to evolution. In the lineages of living beings, whenever absent-minded Venus has taken the upper hand, forms have forgotten to make progress. It is only the husbandman that has improved strains, and he has done so by bullying, enslaving, and segregating. All these methods, of course, have made for sad, alienated animals, but they have not resulted in new species. Left to themselves, domesticated breeds would either die out or revert to the wild state—scarcely a commendable model for nature’s progress.
(snip a few paragraphs on peppered moths)
Natural Selection, which indeed occurs in nature (as Bishop Wilberforce, too, was perfectly aware), mainly has the effect of maintaining equilibrium and stability. It eliminates all those that dare depart from the type—the eccentrics and the adventurers and the marginal sort. It is ever adjusting populations, but it does so in each case by bringing them back to the norm. We read in the textbooks that, when environmental conditions change, the selection process may produce a shift in a population’s mean values, by a process known as adaptation. If the climate turns very cold, the cold-adapted beings are favored relative to others.; if it becomes windy, the wind blows away those that are most exposed; if an illness breaks out, those in questionable health will be lost. But all these artful guiles serve their purpose only until the clouds blow away. The species, in fact, is an organic entity, a typical form, which may deviate only to return to the furrow of its destiny; it may wander from the band only to find its proper place by returning to the gang.
Everything that disassembles, upsets proportions or becomes distorted in any way is sooner or later brought back to the type. There has been a tendency to confuse fleeting adjustments with grand destinies, minor shrewdness with signs of the times.
It is true that species may lose something on the way—the mole its eyes, say, and the succulent plant its leaves, never to recover them again. But here we are dealing with unhappy, mutilated species, at the margins of their area of distribution—the extreme and the specialized. These are species with no future; they are not pioneers, but prisoners in nature’s penitentiary.—geneticist Giuseppe Sermonti in “Why is a Fly Not a Horse?”
And to show that at least one evolutionist doesn't understand natural selection I give you:
the Pixie at Telic Thoughts: Understanding science
Natural selection is guided by the needs of the organism or species in that environment.
That's too funny...