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Convergent evolution of pythons, boas

Damien Esquerre with a python/Stuart Hay, ANU

From ScienceDaily:

The Australian National University (ANU) study found that by living in the same habitat, pythons and boas evolved independently to look similar. This happened at least five times in different habitats. Aquatic pythons look like aquatic boas, burrowing pythons look like borrowing boas and tree-dwelling pythons look like tree-dwelling boas.

Other famous examples of convergent evolution are sharks and dolphins, which are not related but have evolved similar body plans. Similarly, the extinct Tasmanian Tiger, a marsupial mammal, and the wolf, a placental mammal, evolved similar body plans.

Esquerre attempts to pin all this on natural selection (Darwinism) and adaptation, then admits:

not all evolution was driven by natural selection, but examples such as pythons and boas reinforce its importance in shaping biological diversity. More. Paper. (paywall) – Damien Esquerré, J. Scott Keogh. Parallel selective pressures drive convergent diversification of phenotypes in pythons and boas. Ecology Letters, 2016; 19 (7): 800 DOI: 10.1111/ele.12620

Actually, convergence challenges claims about natural selection.

Sharks are fish and dolphins are mammals, believed to have once been land dwellers that later adopted an aquatic lifestyle. Marsupials and placentals are very different type of mammals. Michael Denton’s argument for common patterns that keep appearing in life forms would fit the situation better than claims about natural selection (where there is no particular reason we should expect to see this level of convergence).

See also: Sometimes Denton sounds like a Darwin who got way more right


Evolution appears to converge on goals—but in Darwinian terms, is that possible?

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Hi, this is Damien Esquerre, of the research. Just wanted to clarify what I am being quoted for: "Esquerre attempts to pin all this on natural selection (Darwinism) and adaptation, then admits: not all evolution was driven by natural selection, but examples such as pythons and boas reinforce its importance in shaping biological diversity." And yes, any biologist knows that evolution is not only driven by natural selection. Natural selection is a process and evolution a product. Evolution can also happen by random changes in gene frequencies within a population (genetic drift), and by sexual and artificial selection, which operate just like natural selection. In sexual selection instead of the environment doing the selection on which individuals inherit their genes to the next generation (so called survival of the fittest), the opposite sex does by choosing who to mate with in sexual selection (for example the evolution of colourful plumages in birds). In artificial selection people choose desirable traits in the animals and plants they breed, to obtain all of the domesticated plants and animals we use today (from corn and apples to dogs and cows). There might be debate on which process predominates under different circumstances, but the scientific community is not at all divided on the fact that not only natural selection can produce evolution. We prove it everyday by creating new kinds of organisms ourselves. So please explain how does convergence challenges claims about natural selection? Convergence is very useful to biologists to find traits that are adaptive. If we see in different groups of animals or plants the same trait evolving under the same condition we have evidence that this trait is an adaptation to that condition. I also want to reply individually to each comment to clarify what I mean and some things that are known about evolution. Mahuna, not sure what you mean what I think you aar talking about how two species cannot have the exact same ecological niche? This is mostly true, but when they coexist. Boas and pythons that have the same ecology live in different continents. The switch to a convergent ecology and form does not have to happen at the same time, it is just solving the same problem with the solution independently (i.e. evolving the same morphology and colour for example, when two species independently become arboreal). Andre, yes, go team python!! Robert Byers: no, the tasmanian wolf or thylacine is not a wolf with a pouch, it may look superficially but a closer look to its bones, its anatomy and its DNA will quickly reveal that it is more related to a kangaroo or an opossum than a wolf. I cannot comment on how many snakes where on the ark since that is not my area of expertise, but if there was only one pair, then did that pair evolve into cobras, worm sized blind snakes and anacondas? So it is impossible the descendants of that pair of snakes adapted through evolution....then how? If you allow the more than 100 millions of years that have had snakes to evolve then you could see the diversity observed today. Of course that is unlikely in the few thousands of years you are allowing, but we now know for sure that snakes have been around for many many millions of years. Thanks a lot for the interest, for the interest and the time to comment. damienesquerre
Also, the many caves around the world that have completely unrelated species (fish, shrimps, lizards) but are white, blind, and have hightened hearing, touch or other senses. This is a gteat example of the environment, and NS creating a convergence of characteristics necessary in a habitat with no light. rvb8
Its not the tasmanian devil that looked like the wolf. The devil is alive and well. The marsupial wolf is extinct. Yes it was just a wolf with a pouch. anyways its welcome about these snakes. There was only one pair of snake on the ark. it could only be that they easily adapt to the areas they moved to. yet impossible that its bu evolution. Imagine all the twists and turns in selection working on mutations that would be needed to bring them to thier present looks. THEN they look exactly alike!! think about it. this convergence is so unlikely. in fact if they looked quite different but still lived in the same niche the evolutionists would be happier. They would say AHA see! Under selection they adapted to like niche but not totally alike. This showing the chance nature of evolution. BUT NO! Instead we find like responce to like need every time. Like a common blueprint that is still in operation to allow creatures to survive. These snakes are a good YEC/ID point if one thinks about why they look alike so much. Robert Byers
Go team Python! Andre
Wouldn't it make more sense, Darwinistically, if the first creature that the superior survival strategy down simply dominated the niche, to the exclusion of competitors? That is, unless BOTH boas and pythons began experimenting with tree climbing at the same precise moment, shouldn't the guy who got the nifty new technique down FIRST have prevented all new competitors from staking out enough territory to reproduce in any significant numbers? Otherwise this looks a LOT like Chevy designing the Camaro to compete with Ford's Mustang, since Chevy's Corvette never competed with Mustangs price-wise. The Corvette was of course Chevy's copy of Ford's Thunderbird, which was an attempt to produce an American copy of a European sports car. All of this FOLLOWED the success of a new model in a new market. This works for carmakers because some car BUYERS have a personal loyalty to a BRAND of car. It makes no sense at all in biological systems where each new generation of a species needs to maximize its success in an ESTABLISHED niche. So, Design Team BOA finds out that Design Team PYTHON is coming out with a new TreeClimber model. So all efforts at Design Team BOA for their new swimming Anaconda knockoff are scaled back and the resources poured into Team BOA's copy of TreeClimber. That makes much more sense. mahuna
not all evolution was driven by natural selection, but examples such as pythons and boas reinforce its importance in shaping biological diversity
This makes sense, Natural selection removes diversity to make everything look the same, I can agree with that type of evolution. Andre

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