Darwin’s finches, we are told, have reached their limits on the Galapagos Islands
The evolution of birds on the Galapagos Islands, the cradle of Darwin’s theory of evolution, is a two-speed process. Most bird species are still diversifying, while the famous Darwin’s finches have already reached an equilibrium, in which new species can only appear when an existing one becomes extinct. This finding expands the classical theory on island evolution put forward in the 1960s.
What? We haven’t even established how many “species” there are anyway, due to hybridization. Nonetheless,
‘The analysis shows that for the finches, diversity does indeed have a negative effect. There is no more room for new species, unless one of the existing species becomes extinct, so the islands are saturated regarding finch-type species’, Etienne explains. This does not mean the radiation is static. ‘We found that the rates of both evolution and extinction are very high for Darwin’s finches. That is probably why these birds have reached an equilibrium.’
Other species like mockingbirds have not yet reached equilibrium, which contrasts sharply with the current view that oceanic islands are at equilibrium. ‘Our data shows that they are evolving more slowly and are still diversifying.’ In a million years or so, more mockingbird species may have appeared — granted that conditions on the islands remain the same. More.
Again, what? Given that a huge hoo-haw ensued some years back when a minor climate change was supposed to be producing new species of finches within a researcher’s career, how likely is it that the conditions for a new species of mockingbird (a million years of eco-stasis) would be met?
I don’t suppose that’s a roundabout way of saying that evolution does not really occur in mockingbirds, but it almost sounds like it.
Here’s the abstract:
Island biotas emerge from the interplay between colonisation, speciation and extinction and are often the scene of spectacular adaptive radiations. A common assumption is that insular diversity is at a dynamic equilibrium, but for remote islands, such as Hawaii or Galapagos, this idea remains untested. Here, we reconstruct the temporal accumulation of terrestrial bird species of the Galapagos using a novel phylogenetic method that estimates rates of biota assembly for an entire community. We show that species richness on the archipelago is in an ascending phase and does not tend towards equilibrium. The majority of the avifauna diversifies at a slow rate, without detectable ecological limits. However, Darwin’s finches form an exception: they rapidly reach a carrying capacity and subsequently follow a coalescent-like diversification process. Together, these results suggest that avian diversity of remote islands is rising, and challenge the mutual exclusivity of the non-equilibrium and equilibrium ecological paradigms. Open access – Luis M. Valente, Albert B. Phillimore, Rampal S. Etienne. Equilibrium and non-equilibrium dynamics simultaneously operate in the Galápagos islands. Ecology Letters, 2015; DOI: 10.1111/ele.12461
Exaggerating the evidence to prop up Darwinism is not new. In the Galápagos finches, average beak depth reverted to normal after the drought ended. There was no net evolution, much less speciation. Yet Coyne writes in Why Evolution Is True that “everything we require of evolution by natural selection was amply documented” by the finch studies. Since scientific theories stand or fall on the evidence, Coyne’s tendency to exaggerate the evidence does not speak well for the theory he is defending. When a 1999 booklet published by The U. S. National Academy of Sciences called the change in finch beaks “a particularly compelling example of speciation,” Berkeley law professor and Darwin critic Phillip E. Johnson wrote in The Wall Street Journal: “When our leading scientists have to resort to the sort of distortion that would land a stock promoter in jail, you know they are in trouble.”
Actually, no, they aren’t. As long as science journalists prefer to be patted on the head and told they are good little cheerleaders rather than to ask serious questions, only science as such is in trouble.
The famous fourth estate (media) has, it seems, been inherited by wastrels and layabouts.
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