Extinctions 'r' us
So far, Earth has undergone five mass extinctions of great numbers of life forms in the last four billion years. Most were the result of a natural course of evolution in which simpler organisms changed into more complex life forms. Others vanished as the result of major uncontrollable forces such as meteor impacts, volcanoes, or periodic tilting of the earth's axis. Each of these forces would have caused drastic changes in Earth's climate, which in turn would effect food sources and the ability of all living things to adapt.
Today's extinctions are also influencing climatic changes. We humans, by destruction of habitat, pollution, deforestation, over-fishing and just abusing the natural world in general, are directly controlling the present rates of extinction. Ecologists estimate that we have lost hundreds of thousands of plant and animal species in the past 50 years. We run the risk of losing one-half of all living species within the next century.
We are the only species in Earth's history cognizant of our ability to influence every other life form in a positive or negative way. Take American alligators. After surviving for over 150 million years, we nearly wiped them out in the 1960s. But we then protected the huge reptiles and placed them on the Endangered species list for a couple of decades. Now they number several million and are found in 11 states.
We are such a contrasting species. Smart, dumb. Evil, good. Giving, greedy. Caring, ruthless. The problem, the solution.