We talk a lot about how species adapt to new environments, and how random mutations favored by natural selection help organisms respond and change. But, on the flip side, there's a simple fact that is often ignored: Sometimes, the random part doesn't play in a species' favor. That's the bear in the honey of an evolutionary system that isn't directed by some outside force. In retrospect, we can look back and see a long line of successful mutations leading up to what exists today. But, in real time, "random" means "random".
Blogger Hannah Waters has a really fascinating post up today, all about what happens when random mutations and natural selection don't help a species adapt to new conditions.
In Prescot, Maryland, a copper refinery opened up next to a meadow that had many species of grasses and wildflowers. Over time, the soil was contaminated by copper, killing off many of the plants. However, after 70 years, there were 5 species that were still able to thrive in these meadows! They had adapted and developed a resistance to copper.
Even now I'm thinking to myself, "oh! cool! How did they adapt that way? How did that mechanism work? How quickly did the resistance gene spread?" etc. But what I'm forgetting is that, while five species did adapt, twenty-one species failed to adapt. If there really was massive diversity at all genes in each population, you would think that at least one would confer some benefit to survive the copper. But this did not happen: twenty-one species went locally extinct.
Just as interesting a question as "How did these 5 adapt?" is "Why did these 21 fail to adapt?" But it's a question that's only begun to be reconsidered. Death and extinction are far more powerful forces in shaping the whole of biodiversity on our planet than successful adaptation, but these evolutionary failures that occur all around us are little studied.
Culturing Science: When Adaptation Doesn't Happen
Image: Some rights reserved by wilbanks
Via Bora Zivkovic
