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  Yahoo News 9 Jan 06
Plants that grow fast may have advantage
By Randoph E. Schmid, AP Science Writer

PlanetArk 9 Jan 07
Warming Could Spur 'Evolution Explosion' - Study
Story by Deborah Zabarenko, Environment Correspondent

WASHINGTON - Fast-growing weeds have evolved over a few generations to adapt to climate change, which could signal the start of an "evolution explosion" in response to global warming, scientists reported on Monday.

This means that the weeds will likely keep up with any attempts to develop crops that can adapt to global warming, said Arthur Weis, a professor of ecology and evolutionary biology at the University of California, Irvine.

But some long-lived species -- like the venerated California redwood tree, with a life-span of hundreds of years -- will not have the capacity to adapt so quickly, because their life cycles are so long, Weis said in a telephone interview.

The quick-growing weedy plant known as field mustard showed the ability to change reproductive patterns over a period of just seven years, Weis said. "If you take a climate shift, such as we've had here in southern California, in a very few number of generations you can get a change in ecologically important traits that can allow these fast-growing weedy species to hang on and actually do well despite the change in environments," he said.

Weis and his colleagues cultivated two sets of mustard seeds in a greenhouse: one set collected in 1997, just before a five-year drought, and a second set collected in 2004, after the drought ended. The plants were divided into three groups, with each getting different amounts of water, ranging from drought-dry to soggy. In every case, the post-drought generation of plants flowered earlier, meaning the plants could produce seeds before the soil dried out. Late-bloomers would wither before any seeds were produced in a drought year.

SPEEDED-UP LIFE-CYCLE

How fast a change is this, on the evolutionary timetable? Weis calculated that this represents a 16 percent acceleration of the mustard plants' life-cycle over seven generations. "That's a pretty big change in age of maturation," he said.

Asked to hypothetically compare this to evolutionary changes in people, Weis offered what he termed a very crude analogy: if humans evolved at the same rate as the mustard plants in the experiment, the average onset of the age of reproduction in humans would slip from 16 years to 13 1/2 in seven generations.

Weis is spearheading a project to collect, dry and freeze seeds from around North America so they can be studied 50 years from now. He figures that global warming will prompt lots of evolutionary changes and scientists will want to have evidence of plants before the changes occurred. The effort is called Project Baseline.

"If global climate change is coming, and it is, we have this huge unplanned experiment in evolutionary biology facing us," Weis said. "Climate change could lead to an evolution explosion. ... This gives scientists an unprecedented opportunity to look at the actual nuts and bolts of evolutionary change."

The idea is for scientists in the mid-21st century to go back to the same locations where plants are being collected and note the differences between the plants from the different time periods. Research by Weis and his team was published in the journal Proceedings of the National Academy of Sciences.

Yahoo News 9 Jan 06
Plants that grow fast may have advantage
By Randoph E. Schmid, AP Science Writer

WASHINGTON - The ability to grow like a weed may be an advantage when it comes to coping with climate change.

Plants with short life cycles can adapt more quickly to change than those that reproduce slowly, according to a new study by researchers at the University of California, Irvine. The findings are reported in Tuesday's issue of Proceedings of the National Academy of Sciences.

"Some species evolve fast enough to keep up with environmental change. Global warming may increase the pace of this change so that certain species may have difficulty keeping up. Plants with longer life cycles will have fewer generations over which to evolve," Arthur Weis, professor of ecology and evolutionary biology, said in a statement.

Weis and colleagues focused on Brassica rapa--field mustard--a plant classified as an annual because it goes from seed to flower and back to seed in one year. That allows for more rapid evolution than something like a redwood, which takes years to reach maturity and reproduce.

The researchers had collected seeds near the school campus in 1997, two years before a long drought set in. They also collected after the drought, in the winter of 2004. Both groups of seeds were then planted at the same time in greenhouses. The post-drought seeds flowered earlier than those collected before the drought, a shift in timing that would enable them to complete seed production before the soil dried out. Plants that bloomed later withered before they could set seed.

"Early winter rainfall did not change much during the drought, but the late winters and springs were unusually dry. This precipitation pattern put a selective pressure on plants to flower earlier," co-author Steven Franks said in a statement.

In a separate paper in the same issue, researchers report that amphibians such as salamanders and frogs appear able to adapt rapidly to changes in the environment.

Kim Roelants of Vrije University in Brussels, Belgium, and colleagues report that they found no major extinctions of amphibians in a study of the fossil record of periods when other land animals were undergoing major extinctions.

Instead, their analysis showed periods when amphibians diversified rapidly, an indication that they coped with change by changing themselves, rather than by dying out.
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