Tuesday, June 26, 2007
Butterfly wings and so much more: An annotated guide to today's evolution edition of Science Times
The patterns on butterfly wings posed some special challenges for evolutionary biologists working within the framework that prevailed until recently, the so-called "modern synthesis." Was each individual pattern a result of numerous discrete genetic mutations, from which the best-adapted were selected by natural selection? And what about species that are copied by other, mimic species, like the monarch and the viceroy? Did the mimics have to duplicate the entire evolutionary history of the original species? The answer, it turns out, is both simpler and more complex, and it's just one of the surprising discoveries of the new combination of evolution and developmental biology -- nicknamed "evo-devo" -- that's bringing the greatest change to our understanding of evolution since the modern synthesis was put together between the 1930s and 1950s.
The changes in today's understanding of evolution -- none of them of much comfort to creationists -- are the subject of today's edition of the NYT Science Times. (I don't know if this is just me, but the section has seemed rather lackluster recently -- today's, however, is spot-on.) This is definitely not your father's evolution. Here's a brief, annotated guide to the coverage.
From a Few Genes, Life’s Myriad Shapes: Fins, feet and Darwin's finches -- Carol Kaesuk Yoon sums up our growing understanding of how a few powerful genes control the development of morphology and pattern in a variety of species.
Darwin Still Rules, but Some Biologists Dream of a Paradigm Shift>: The gene used to be seen as an authoritarian boss, dictating from on high. It turns out that development makes for a more flexible, messy and robust org chart than the old top-down command structure, according to Douglas H. Erwin's essay.
Humans Have Spread Globally, and Evolved Locally: The emergence of lactose tolerance among the cattle-raising people of northern Europe is just one example, Nicholas Wade reports.
Fast-Reproducing Microbes Provide a Window on Natural Selection: Carl Zimmer writes about observing the process of natural selection in a setting where it happens fast enough to be observed.
The Human Family Tree Has Become a Bush With Many Branches: Genetics, molecular biology and paleoanthropology are all contributing insights that help sketch the branches of the human ancestral family tree, according to John Noble Wilford.
Human DNA, the Ultimate Spot for Secret Messages (Are Some There Now?): Now that scientists have succeeded in writing a message on bacterial DNA, could our "junk DNA" also be used to carry messages? Or does it already? Dennis Overbye speculates in this essay.
In Parasite Survival, Ploys to Get Help From a Host: Is the toxoplasma parasite from the litter in your cat box controlling your behavior? Stranger things have happened, according to Natalie Angier.
Science of the Soul? ‘I Think, Therefore I Am’ Is Losing Force: The old Cartesian split between humans (with a soul) and animals (without) is breaking down under the impact of the findings of evolutionary biology, Cornelia Dean writes. Either we all have souls, or none of us do, it seems.