Tuesday, May 22, 2007

Becca's New and Hot-- Week 8

This article caught my eye because I'm studying climate change for another class, but it turns out that global warming and evolution are very much related! The article starts off with what is by now fairly obvious: scientific evidence confirms that humans are to blame for global warming, and human action is decimating biodiversity. What follows is much more novel, though: global warming and other human activities, such as commercial fishing, in recent decades have driven species to "evolve and adapt at unexpected speed to new living conditions." The first example given is that of codfish, a species that has been overfished in recent decades. Scientists have found now that the codfish has adapted to the younger age structure that overfishing creates-- because older, bigger fish are caught first-- by changing the age of sexual maturity from 10 to 6 years old. Another example of quick evolution provoked by human activity is with birds in cities; new singing patterns and earlier mating have been observed in urban areas, and specifically, the white-tailed eagle (previously thought to exist only in large, old forests) can breed in the middle of a city as long as it finds the right food. How does all of this relate to global warming, you might wonder? The latest Intergovernmental Panel on Climate Change report data shows that "climate change is likely to affect forest expansion and migration, and exacerbate threats to biodiversity resulting from land use/cover change... Marine and coastal ecosystems in Asia are likely to be affected by sea level rise and temperature increases." The speed with which species can adapt and evolve will determine whether or not they survive these changes. Of course, an important thing to keep in mind when reading an article like this is that there is no end goal; rather, those individuals that survive in new ecosystems will be the ones to reproduce. This is a very interesting example of natural selection at work!

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