Evolution (Evolution)

by dhw, Thursday, February 05, 2009, 12:39 (5558 days ago) @ David Turell

Once again, many thanks to David for these references. The snake hit the front page of today's Guardian, and then spread itself out on page 3. - The Tree of Life article is fascinating, but somewhat confusing. At one point Graham Lawton says the project (building a tree of life) "lies in tatters, torn to pieces by an onslaught of negative evidence. Many biologists now argue that the tree concept is obsolete and needs to be discarded." However, on page 4 he says: "Nobody is arguing ... yet ... that the tree concept has outlived its usefulness in animals and plants. While vertical descent is no longer the only game in town, it is still the best way of explaining how multicellular organisms are related to one another ... a tree of 51 per cent maybe. In that respect, Darwin's vision has triumphed: he knew nothing of micro-organisms and built his theory on the plants and animals he could see around him." - He also says that both Bapteste and Doolittle "are at pains to stress that downgrading the tree of life doesn't mean that the theory of evolution is wrong ... just that evolution is not as tidy as we would like to believe." (I wonder who he means by "we".) And yet later he talks of "the uprooting of the tree of life". Downgrading and uprooting are not the same thing at all, and expressions like "torn to pieces" and "onslaught of negative evidence" smack of fundamentalism when set against the statement on page 2: "The debate remains polarised today." Clearly there is no consensus. - The whole kerfuffle seems to be about the discovery of horizontal gene transfer, and some scientists now prefer the metaphor of the web as opposed to the tree. Well, if the argument is just about horizontal and vertical, with vertical still the best way of explaining animals and plants, maybe Darwin simply drew the wrong tree. How about a cedar?