Ecology professor and evolutionary biologist Arthur Weis and colleagues from the University of California, Irvine cultivated two sets of seeds from the fast-growing weed known as field mustard in a greenhouse. One set of seeds was collected just before a five-year drought in 1997, and the second set was gathered in 2004. They divided the resulting plants into three groups, and watered each of them in a way that mimicked conditions from drought to heavy rains. In all cases, the plants grown from the seeds gathered in 2004 flowered earlier and were therefore able to produce seeds before the soil was too dry.
On an evolutionary timetable, the weed's rapid shift in reproductive patterns is equivalent to a 16 percent acceleration of its lifecycle in just seven generations, Weis said. If human beings evolved at the same rate in seven generations, he said, the average age of reproduction would drop from 16 years old to about halfway through the age of 13. Although he noted that something with a longer lifespan, such as a California redwood -- which can live hundreds of years -- would not adjust as rapidly.
Weis is now at the forefront of Project Baseline, in which seeds will be collected from around North America so they can be dried and frozen for study in about 50 years. He theorizes that the seeds will give scientists of the time a basis for comparison to any evolutionary changes that may have occurred due to climate change.
"If global climate change is coming, and it is, we have this huge unplanned experiment in evolutionary biology facing us," he said. "Climate change could lead to an evolution explosion."
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