Evolution

The grapevine (Vitis vinifera) is a widely cultivated crop that has been subjected to intensive breeding since the Neolithic period (from ~10,500 to ~6,000 years ago). The domestication of grapevine has undergone a selection for traits important for its cultivation and usage. The recent publication of the complete grapevine genome has opened the possibility for an in-depth analysis of its content. This sequencing has shown that genes constitute only a very small proportion of complex genomes, with repetitive sequences and (in particular) mobile genetic elements or transposons making up a much…

The ostentatious, sometimes bizarre qualities that improve a creature's chances of finding a mate may also drive the reproductive separation of populations and the evolution of new species, say two Indiana University at Bloomington biologists. In the September 2008 issue of Evolution, Armin Moczek and Harald Parzer examine males from four geographically separated populations of the horned beetle species Onthophagus taurus. The beetles have diverged significantly in the size of the male copulatory organ, and natural selection operating on the other end of the animal -- horns atop the beetles'…

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I have made the point several times on this blog that creationists (among whom I squarely classify so-called intelligent design proponents) simply don’t get it (or refuse to get it) when they claim that scientific controversies are a sign that there is something seriously wrong with science. Au contraire, mon amis, science makes conceptual progress largely through discussions and disagreements among scientists, which eventually get settled because of new empirical discoveries. Now, controversies about the Bible, on the other hand... But I digress. The latest round of vigorous debate in…

For Charles Darwin, the problem of the peacock's tail, in light of his theory of natural selection, was vexing in the extreme. Indeed, in 1860, writing to Asa Gray, his most ardent American champion, Darwin confessed: "The sight of a feather in a peacock's tail, whenever I gaze at it, makes me sick!" In his struggle to explain why such extravagant and seemingly burdensome features existed, the great English naturalist struck upon the idea of sexual selection -- that showy traits such as the Peacock's ornamentation were an advantage in the mating game that outweighed other disadvantages. A…

Part 2 on The Plausibility of Life How does evolution shape living things? The fact that evolutionary forces, such as natural selection, can shape living creatures is well-established, but how malleable those creatures are, and what the increments of change are is less well established. We have a fairly good idea of how genes can change, but how does that genetic change translate into physical changes in the shape and functioning of the organism itself - that is, how does genetic change translate into changes in the organism's phenotype? The authors of The Plausibility of Life, Marc…

Ever since Darwin, evolutionary biologists have wondered why some lineages have diversified more than others. A classical explanation is that a higher rate of diversification reflects increased ecological opportunities that led to a rapid adaptive radiation of a clade. A textbook example is Darwin finches from Galapagos, whose ancestor colonized a competitors-free archipelago and rapidly radiated in 13 species, each one adapted to use the food resources in a different way. This and other examples have led some to think that the progenitors of the major evolutionary radiations are those that…

Researchers have tackled the problem of cooperation (and the related one of the evolution of altruism) for some time now. Initial game theory models suggested that cooperative animals would quickly be supplanted by selfish ones because of a cost to cooperation, as in the the so-called simple prisoners’ dilemma. In these situations, typically an individual can choose between an action that benefits everyone, but at a cost to oneself, and an action that clearly benefits the individual, but comes at the risk of greater loss if everyone adopts that strategy. It turns out that most of us would…

Quick; who is against evolution the most? Right wing, religious fundamentalists or left-wing academics? Well, you're right. Both sides have something to fear and both sides attack evolution in order to keep their world view intact. The worst thing for a humanities professor who has spent his life dissecting the impact of social learning and culture is to find out there may actually be genetic distinctions that promote inequality. If you're a biologist, it's a strange fear because the exact opposite is true; evolution offers a way for everyone to share genetic commonality. But biologists…

Metabolic changes responsible for the evolution of our unique cognitive abilities indicate that the brain may have been pushed to the limit of its capabilities, according to research published today in Genome Biology. This adds weight to the theory that schizophrenia is a costly by-product of human brain evolution. Philipp Khaitovich, from the Max Planck Institute for Evolutionary Anthropology and the Shanghai branch of the Chinese Academy of Sciences, led a collaboration of researchers from Cambridge, Leipzig and Shanghai who investigated brains from healthy and schizophrenic humans and…