Wednesday, November 11, 2009

Water and Evolution

I look out at the expanse of water in front of me and try to imagine it gone. Seems impossible, doesn’t it, and yet vast bodies of water have disappeared from the earth, or at least have been substantially diminished in size. It can happen.

What makes me think of this today is the PBS Nova Series, Becoming Human. The three part series, two of which have already been aired, reports on recent findings about the evolution of primates to Homo sapiens. They ask the question why did our ancestors start to walk upright and what caused their brains to grow.

Anthropologists concentrate their searches in eastern Africa, in the Great Rift Valley. What I learned is that millions of years ago there used to be a huge freshwater lake in this now arid part of the African continent. The water levels of that body of water fluctuated, due to periods of excess rain and drought. This is proven in the geological layers by the presence of diatoms, unicellular organisms that only exist in water. Scientists think that one of the ways that mammals adapted to this climate instability was by increasing the size of their brain.

The water levels of the lake outside my window fluctuate, too, but not that dramatically. Here’s an excerpt from the November 6 report on Great Lakes Water Levels as posted at Great Lakes Observing System website:

Water Level Conditions: All of the Great Lakes remain higher than their levels of a year ago. Lakes Superior, Michigan-Huron, St. Clair, Erie and Ontario are 3, 12, 8, 6, and 1 inches, respectively, higher than their levels last year at this time. The water levels of Lakes Superior, Michigan-Huron and St. Clair are expected to decline by 2 inches over the next month. Lake Erie and Ontario are expected to decline 1 and 2 inches, respectively, over the next 30 days. Over the next several months, Lake Superior, Lake Michigan-Huron and Lake St. Clair are forecasted to be above their water levels of a year ago. Lakes Erie and Ontario are forecasted to remain near or below last year's levels over the same time period

Still, it makes me wonder what changes will take place in our species as our own climate instability progresses. And yes, I do believe our climate is changing, although I also believe climate has always changed. But the rate of change has increased and been influenced by us Homo sapiens and our larger brains, as well as our cars, our factories, our plastic bottles and myriad other modern inventions.

Evolution is an ongoing process, but how will humans change in response to an unstable climate? How will we adapt? Will we have bigger brains instead of bigger cars? Will be go back to walking on two feet instead of driving on four wheels? Will our feet be bigger? Our arms longer? Our skin thicker? What do you think?

The picture at the right has nothing to do with evolution, but I wanted to share it. It was taken last weekend at the Japanese Garden in the Brooklyn Botanical Gardens , which I think is a highly evolved and beautiful place.

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