Chasing Beetles. Recent Salamander Evolution. Accurate Predictions. The Eye. News - Speciation Observed Today. Foxes - Ten Years. Giraffe Dissection 1. Giraffe Dissection 2. Giraffe Dissection 3. Giraffe Dissection 4. Giraffe Dissection 5. Birth of New Species. On one of the Galapagos islands whose finches shaped the theories of a young Charles Darwin, biologists have witnessed that elusive moment when a single species splits in two. In many ways, the split followed predictable patterns, requiring a hybrid newcomer who’d already taken baby steps down a new evolutionary path.
But playing an unexpected part was chance, and the newcomer singing his own special song. This miniature evolutionary saga is described in a paper published Monday in the Proceedings of the National Academy of Sciences. It’s authored by Peter and Rosemary Grant, a husband-and-wife team who have spent much of the last 36 years studying a group of bird species known collectively as Darwin’s finches. The finches — or, technically, tanagers — have adapted to the conditions of each island in the Galapagos, and they provided Darwin with a clear snapshot of evolutionary divergence when he sailed there on the HMS Beagle.
These tunes set the sons apart, as did their unusual size. Beetles Speciation. 2 November 2009 by Kate Melville Tiny leaf beetles that flit among the maple and willow trees in Vermont are providing scientists with some of the clearest evidence yet that environmental factors play a major role in the formation of new species. Vanderbilt University researcher Daniel Funk has been studying this odd group of leaf beetles (which resemble unappetizing caterpillar pellets) for 15 years. In recent years he and co-researcher Scott Egan have used Vermont populations that associate with red maples and Bebbs willows to investigate how divergent ecological habits promote speciation.
Their past observations have suggested that such "maple leaf beetles" and "willow leaf beetles" may be in the process of dividing into two new species: Each prefers to feed and lay eggs on their own "host plant," where they grow and survive best. Evolutionary biologists consider growth rate as a measure of survivability or fitness. Human Evolution Proof. Evolution in Action. Recent Genetic Evolution. Bacteria Evolve. A major evolutionary innovation has unfurled right in front of researchers' eyes.
It's the first time evolution has been caught in the act of making such a rare and complex new trait. And because the species in question is a bacterium, scientists have been able to replay history to show how this evolutionary novelty grew from the accumulation of unpredictable, chance events. Twenty years ago, evolutionary biologist Richard Lenski of Michigan State University in East Lansing, US, took a single Escherichia coli bacterium and used its descendants to found 12 laboratory populations. The 12 have been growing ever since, gradually accumulating mutations and evolving for more than 44,000 generations, while Lenski watches what happens. Profound change Mostly, the patterns Lenski saw were similar in each separate population. All 12 evolved larger cells, for example, as well as faster growth rates on the glucose they were fed, and lower peak population densities.
Rare mutation? Evidence of evolution. Proof of Evolution: Evolution Observed.