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Evolutionary Proof That Eating The Chicken Came Before The Egg
Las Vegas NV (SPX) Apr 13, 2006 In a new study from the May issue of the American Naturalist, Alan de Queiroz and Javier Rodriguez-Robles (University of Nevada, Las Vegas) test Darwin's theory that many current traits can be explained by the ancestral lineage of a species. For instance, predators that have evolved a taste for a certain prey, can go on to develop a taste for the prey's eggs. "Feeding on the eggs of birds or of squamate reptiles (lizards and snakes) tends to occur in lineages that already feed on birds or squamates," explain the authors. Specifically, the researchers examined snakes that have specialized in eating eggs, finding that, in this case, the chicken came before the egg. The researchers compared the family tree for four snake species that specialize in eating eggs and found that their ancestors originally ate the lizards that lay the eggs. It might just be that the eggs are in the same location, but there is another possibility. Snakes use chemical cues to recognize prey, and the authors suggest that these snakes may recognize eggs as potential food because of the chemical similarities between eggs and the corresponding animals, just as some insects are attracted to novel food plants that share chemicals with the insects' typical food sources. "The effects of predispositions on the origins of egg-eating and, ultimately, the evolution of highly specialized egg-eating taxa, represent subtle but important historical influences on the present-day attributes of species," conclude the authors. Founded in 1867, The American Naturalist is one of the world's most renowned, peer-reviewed publications in ecology, evolution, and population and integrative biology research. AN emphasizes sophisticated methodologies and innovative theoretical syntheses--all in an effort to advance the knowledge of organic evolution and other broad biological principles. Community Email This Article Comment On This Article Related Links University of Nevada, Las Vegas American Naturalist Darwin Today At TerraDaily.com
Indian Zoo Clueless About Missing Bear
New Delhi (AFP) Apr 12, 2006It's big, black and dangerous and could be roaming about the Indian capital. New Delhi zoo would like to hear urgently from anyone who spots a Himalayan bear missing since February. The story is embarrassing zoo authorities who Tuesday declined official comment. |
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