The (ongoing) evolution of evolutionary theory

[josephpalazzo]

http://scientiasalon.wordpress.com/2014/11/10/the-ongoing-evolution-of-evolutionary-theory/

[Solitary]

Thanks Joseph! That book makes evolution seem way more complicated than it is now. It over analyzes how it came about, like Combining Einsteins physics with Newtons and quantum mechanics, and making them all absolute when Einsteins and quantum mechanics are just more advanced ways to think about it. It makes it seem like Darwin's evolutionary theory is wrong because it has been tweaked. And worse, by making Creationism seem right. I can't wait to hear what the Creationists have to say about the book. As always, just my opinion, or not. Solitary

[stromboli]

The twin foundational concepts underlying the Darwinian theory are common descent and natural selection. The idea is that all living organisms are related to each other, and that the major (though, crucially, even then, not the only) mechanism that explains their diversification through time is natural selection. Moreover, natural selection is the mechanism responsible for adaptation, i.e., the functional match between organismal characteristics and the environments in which the relevant organisms live.

The first major improvement on the original Darwinism, which came to be known as neo-Darwinism (and which to this day even practitioners of the field confuse with the later Modern Synthesis!) came at the hands of Wallace himself, together with developmental biologist August Weismann. You see, the problem is that Darwin didn’t have a mechanism of heredity handy (despite the fact that, unbeknownst to him, Mendel had published his work on pea plants in 1866, while Darwin was alive and well). So Darwin flirted with a bit of Lamarckism (inheritance of acquired characteristics), and even proposed his own half baked theory of blended inheritance. Wallace and Weismann sought to get rid of the Lamarckian stigma once and for all, which they accomplished via Weismann’s famous doctrine of the separation between somatic (i.e., non reproductive) and germ (i.e., reproductive) cell lines: even if the environment influences the makeup of somatic cells, these have no way to pass that information down to new generations, so Lamarckism is ruled out. (In reality things are much more complex, for instance because plants and a number of other organisms do not obey the Weismannian doctrine.)

A small group of brilliant mathematical biologists came to the rescue, chiefly Ronald Fisher, followed by J.B.S. Haldane and Sewall Wright. Fisher was almost single-handedly responsible for the reconciliation (i.e., the “synthesis”) between Mendelism, Mutationism and (neo)Darwinism: he showed how, assuming (as it turned out to be the case) that phenotypic characteristics are influenced by a relatively large number of genes, the statistical effects of those genes (and their interactions with the environment) creates precisely the sort of continuous distribution of characteristics that Darwin thought would allow natural selection to work. Indeed, Fisher formalized the Darwinian insight in mathematical form, arriving at what still today is a cardinal idea in population genetics, his Fundamental Theorem of Natural Selection [11].

Good article. This is a very informative overview for people who aren't familiar with the internal debate among biologists on the subject.

I'd like to see discussion of the causal relationship of climate and geologic changes to evolutionary punctuality. I have read accounts of adaptive behavior in the short term of certain animals in relation to global warming, the beaching of walruses and seals lacking ice to float on, and changes in diet driven by loss of primary food sources; the bears in Canada now consuming shrubs that have grown where permafrost has melted, and so on. We have also seen short term shifts in coloration of rats from light to dark, both in the desert and cities

http://www.nytimes.com/2011/08/09/science/09mouse.html?pagewanted=all&_r=0

Also adaptive behavior and changes in humans. We are genetically very similar across the board from dark African to Native American to Australian Bushmen to tall and blonde Nordic types. All closely related yet markedly dissimilar in appearance. THIS is the kind of stuff I like to see on the forum. Thanks, JP. I appreciate it.

(edit) I'm going to look up Pigliucci and do some reading. this guy seems to have his shit together.