We still do not see any evidence that they broke out of the niche went beyond it in an evolutionary sense as Darwin imagined would happen with the flying fish.
Darwin didn't imagine it
would happen. The flying fish example was, in Darwin's own words, an "imaginary illustration". If you care to read Chapter 6 of the origin of species you will see what he is illustrating.
He imagined it might have been modified into that perfectly winged animal.
More accurately he is asking the reader to imagine the initial population sizes of fish that are using wings for full flight. That is to say: such a population would start off small until that population adapted to be good at it.
Darwin is simply anticipating the objections surrounding transitions between major ecologies (notably land to water but his flying fish illustration is Darwin showing the concept working backwards). He accepts that he is lacking in evidence on this point, but goes on to hypothesise some possible solutions to the objections. He didn't use his theory to predict that within the next 150 years flying fish would literally become as adept at flying as bats are.
In this manner the gliding frog, snake, lizard, fish, mammal, and marsupial all share the end point, in that way these creatures are failures of his theory to substantiate macro-evolution.
And yet, in the same chapter that you quoted, Darwin wrote:
quote:
has been asked by the opponents of such views as I hold, how, for instance, a land carnivorous animal could have been converted into one with aquatic habits; for how could the animal in its transitional state have subsisted?
And he goes on to comment
quote:
Look at the family of squirrels; here we have the finest gradation from animals with their tails only slightly flattened, and from others, as Sir J. Richardson has remarked, with the posterior part of their bodies rather wide and with the skin on their flanks rather full, to the so-called flying squirrels; and flying squirrels have their limbs and even the base of the tail united by a broad expanse of skin, which serves as a parachute and allows them to glide through the air to an astonishing distance from tree to tree. We cannot doubt that each structure is of use to each kind of squirrel in its own country, by enabling it to escape birds or beasts of prey, or to collect food more quickly, or, as there is reason to believe, by lessening the danger from occasional falls. But it does not follow from this fact that the structure of each squirrel is the best that it is possible to conceive under all natural conditions. Let the climate and vegetation change, let other competing rodents or new beasts of prey immigrate, or old ones become modified, and all analogy would lead us to believe that some at least of the squirrels would decrease in numbers or become exterminated, unless they also became modified and improved in structure in a corresponding manner. Therefore, I can see no difficulty, more especially under changing conditions of life, in the continued preservation of individuals with fuller and fuller flank-membranes, each modification being useful, each being propagated, until by the accumulated effects of this process of natural selection, a perfect so-called flying squirrel was produced.
So he predicts that natural selection will lead to increasingly more fit flying squirrels. So how, exactly, are they 'failures' when he was aware of them and discussed them in the 'Origins...'?
Also, a failed prediction by Darwin is not relevant since original Darwinism has been abandoned. Or rather, the good bits were kept, the bad bits (and there were plenty) were expunged. Then the good bits from other ideas were integrated into the good bits of Darwin's ideas to create what might be called a modern synthesis of ideas like sixty years ago.
Finally, problems (real or imagined) to Darwin's imagination are do not demonstrate any kind of barrier that would prevent the kind of evolutionary change the evidence would otherwise indicate has actually happened.
Edited by Modulous, : This is my 3000th post. Gives me an average of 2.2 posts every day for 3 years and 9 months. Shocking.
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