Evolution

From “Mystery of Disappearing Bird Digit Solved?” (ScienceDaily, Sep. 4, 2011), we learn the answer to one of life’s little mysteries: How does the three-toed bird foot map onto the five-toed mammal foot: Evolution adds and subtracts, and nowhere is this math more evident than in vertebrates, which are programmed to have five digits on each limb. But many species do not. Snakes, of course, have no digits, and birds have three. Yale scientists now have a good handle on how these developmental changes are orchestrated in the embryo. But there is still one outstanding debate on birds: Which digits are they? A thumb with index and middle fingers, or the index, middle and ring fingers? As it turns out, Read More ›

From “Woolly Rhino Fossil Discovery in Tibet Provides Important Clues to Evolution of Ice Age Giants” (ScienceDaily, Sep. 2, 2011), we learn: A new paper published in the journal Science reveals the discovery of a primitive woolly rhino fossil in the Himalayas, which suggests some giant mammals first evolved in present-day Tibet before the beginning of the Ice Age. The extinction of Ice Age giants such as woolly mammoths and rhinos, giant sloths, and saber-tooth cats has been widely studied, but much less is known about where these giants came from, and how they acquired their adaptations for living in a cold environment. The new rhino is 3.6 million years old (middle Pliocene), much older and more primitive than its Read More ›

In “Genetics Paper Retracted: Due to statistical errors, a Science paper claiming that mutation is responsible for genetic variation is retracted” (The Scientist September 2, 2011), Jessica P. Johnson reports, A May 2010 Science paper showing that the most genetically fit cow-pea weevils have fewer deleterious genetic mutations in their genomes than their less fit counterparts was retracted yesterday (September 1) by the authors because of flaws in their statistical analysis. The results apparently supported the hypothesis that individuals with the fewest bad mutations will produce the most fit offspring. The revised data analysis, which shows little effect on fitness due to mutation, suggests that some other mechanism may instead be responsible for maintaining genetic variation in weevil populations. Wonder Read More ›

From “Mysterious Fossils Provide New Clues to Insect Evolution” (ScienceDaily, Aug. 15, 2011) , we learn: Scientists at the Stuttgart Natural History Museum and colleagues have discovered a new insect order from the Lower Cretaceous of South America. Though thought to be mayflies, Coxoplectoptera, however, significantly differ from both mayflies and all other known insects in anatomy and mode of life. The peculiar larvae, however, are reminiscent of freshwater shrimps. Their lifestyle turned out to be a major enigma: their mode of embedding and certain other characteristics clearly suggest a fluvial habitat. Their unique anatomy indicates that these animals were ambush predators living partly dug in the river bed. If so, all this raises another evolution conundrum: Darwinism (natural selection Read More ›