A Day in the Life of an Evolutionary Biologist

first_imgMeet Dr. Judith X. Becerra.  She is an expert on plants of Mexico.  Her latest research strove to determine the rate of evolutionary diversification of a genus of trees with a name similar to her own surname: Bursera.  These trees inhabit a range of biomes in the tropical dry forests of Mexico and are well adapted to the local conditions.    Dr. Becerra divided the groupings of Bursera into 10 geographical regions then performed molecular comparisons to produce a phylogenetic tree of the genus.  She concluded that the crown group began to diversify about 60 million years ago, slowly at first, then radiated more rapidly into additional species as the mountains were forming, but before the Baja Peninsula broke off, floated away, and reattached to the mainland.  She deduced that the most rapid diversification occurred between 30 and 7.5 million years ago, with a peak at 13.5 mya – mostly in 5 of the 10 geographical areas.  Since then, the rate of diversification has slowed to a crawl, in her opinion because “the opportunity for diversification of Bursera has declined as the possibilities for further geographical expansion of the tropical dry forest have declined.”    Her results were written up and published in the Proceedings of the National Academy of Sciences.11Judith X. Becerra, “Evolution: Timing the origin and expansion of the Mexican tropical dry forest,” Proceedings of the National Academy of Sciences USA, 10.1073/pnas.0409127102, published online before print July 20, 2005.What follows is not to be taken in any way as a disparagement of Dr. Becerra and her efforts.  Unless proven otherwise (which seems highly unlikely), we should assume her a bright, active, diligent scientist, respected among peers, fulfilling her career as an evolutionary biologist with exemplary field work and analysis.  Her paper looks like standard research fare, complete with dozens of references, graphs, diagrams, equations, and all that would be expected in a scientific paper.  She made observations, proposed a hypothesis, tested it, and made conclusions.  Who could possibly criticize such a constructive enterprise, undertaken simply with the desire to shed light on the history of a particular group of plants?    We want to explore this otherwise ho-hum paper that, for the majority of the population, will pass unnoticed into the growing corpus of scientific literature, where it will rest in peace except to a few specialists.  We want to use it as a case study in how the theory of evolution has become a self-perpetuating job security program with no necessary connection to the truth.    Read this paper carefully, and you will find many useful facts about Bursera, but none that substantiate the two requirements to convince someone of evolution: proof of (1) long ages and (2) the creative powers of natural selection to produce novel structures.  On the contrary, every support for these claims comes from evolutionary assumptions, so it is inbred reasoning, like asking a Wahabi if the Koran is the word of Allah.  Would her support convince a creationist, or a neutral juror with mind uncluttered by evolutionary assumptions?    The phylogenetic tree-making depends on assumptions of evolution.  The calibration of millions of years depends on evolutionary geological assumptions.  The story of diversification depends on the belief that niches create innovation: the “if you build it, they will come” theory of evolution.  This paper is shot through with evolutionary assumptions from beginning to end; evolution calibrates itself by evolution.    Whenever there is an anomaly in the data, she patches up the evolutionary story with additional ad hoc assumptions: the diversification rate changed here or there, in this region but not that one because maybe the mountains were building faster there, etc.  She picks and chooses data based on evolutionary assumptions so as not to clutter the picture she is trying to present: for instance, ignoring certain species to avoid contamination of the story.  She used two separate equations to cross-check each other, ignoring the fact that both depend on evolutionary assumptions; whenever their results don’t agree, there is enough tweak space to get them to line up.  Fossils?  “Due to a scant fossil record,” she admits, “the history of the Mexican dry forest is still sketchy.  Although the floral affinities with other parts of the world, as well as the importance of the endemic elements, have been well established, little is yet known about the timing of the origin of this vegetation and the directions of its historical expansion or contraction.”  No matter – the story is the thing.    Again, this is not to pick on Dr. Becerra; this paper can be considered a rather ordinary sample of evolutionary research.  Being largely a story of microevolution between members of a single genus, it isn’t even all that controversial.  The point is, it underscores the contention (see 12/22/2003 commentary) that Darwinian evolution has become job security for storytellers.  When you see an evolutionary story, no matter how professionally typed, no matter how many references, now matter how many nice graphs and charts and equations, you need to ask yourself how on earth the researcher knows what happened millions of years ago when he or she was not even there to observe it.  To an evolutionist, it doesn’t really matter.  It gives academics and naturalists something to do.  It supports the publishing industry.  It gives Darwinism an air of scientific respectability.  Why, every evolutionist agrees this is the way science is to be done (don’t ask non-evolutionists for their opinion—they are disqualified by definition).  This policy protects Darwinism from cross-pollination of ideas, so that the inbreeding can continue.    Thus, evolutionary biology marches on.  The idea that 30 million years ago, this particular genus of plants began to diversify as mountains were rising, till around 7.5 million years ago it had filled all the available niches, makes a nice, plausible-sounding, self-consistent, albeit malleable, story.  Some of us have the gall to ask, Is it true?(Visited 127 times, 1 visits today)FacebookTwitterPinterestSave分享0last_img

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