Sudden Climate Change Forced Evolution: Scientists
Early humans saw woodland shift to grassland
By Neal Colgrass, Newser Staff
Posted Dec 26, 2012 2:30 PM CST
Updated Dec 29, 2012 7:00 PM CST
This undated handout photo shows the casts of two palates demonstrates the large size of the teeth of Paranthropus boisei (left), an early human relative that lived in East Africa.   (AP Photo/Melissa Lutz Blouin, University of Arkansas)

(Newser) – Early humans evolved in fits and starts due to rapid environmental changes—not gradually as scientists used to think, according to a new study. Analyzing lake sediments in northern Tanzania, scientists from Penn State and Rutgers University concluded that climate change altered the landscape back and forth from grassland to woodland five or six times over 200,000 years, the Telegraph reports. That would have changed food availability, diet, and means of acquiring food—which "can trigger evolutionary mechanisms," says Penn State professor Katherine Freeman.

"The result can be increased brain size and cognition, changes in locomotion and even social changes—how you interact with others in a group." Several factors may have triggered the climate changes about 2 million years ago, including changes in sea temperature and the Earth's movement around the sun. Any change in the amount of sunshine, for example, would have altered rain patterns that in turn affected plant patterns. "The research points to the importance of water in an arid landscape like Africa," says a graduate student on the project. The findings conflict with the "Great Drying," the view that Africa gradually dried out over 3 million years.

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Dec 31, 2012 5:02 PM CST
pssst ... any persistent climate change will "force" evolution. "Evolution" is the success over time of traits best suited to the environment. If the environment changes, those with traits best suited to meet the change survive and those traits are passed on. Over time the result is called "evolution." If the environment changes suddenly and drastically, only a few individuals may survive and they may be individuals possessing what would have been pretty radically different traits from their peers. Nevertheless, they survive and pass on those traits, just because they're better suited to the new conditions. This may appear as "rapid evolution." No es misterioso.
Dec 30, 2012 4:57 PM CST
Correct me if I am wrong, but "evolving" almost always mean the population leaves something behind. Rarely does it mean that we mutate and gain something. Hence, the core of who we are must have been with us for a very long time. In fact, how the heck did we get that core? That is the question on my mind.
Dec 30, 2012 2:27 PM CST
i've said it for years... 95% of all evolutionary changes in animal lifeforms are geared toward the finding or acquiring of food.