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Description Species of organisms come and go over millions of years. Microorganisms were the first to arrive, have evolved, but remained a part of the biosphere. Sea animal species came about later and some worked their way on land. Animals became larger such as the dinosaurs. Every species found a niche in the environment, a member of the food chain. The number of species and the number of organisms in each genus grew and shrunk as the environment changed over the eons. Ice Ages and giant meteorites caused very drastic changes in the environment. So are humans these days. The globe has risen 1 degree Celsius in the last century, most of that change since 1970. The ten hottest years of the past half-millennium have occurred since 1990. To humans, it may not seem like much. Put on the A/C a few more days a year and we never know the difference. Other organisms cannot change their habits as easy. The symbiotic nature of well, Nature, has been established for millenniums. When birds migrate south a few days later than they used to, or salmon migrate up their natal stream at a different time, members of the food chain they are a part of cannot look at their food's daily planner to see that dinner is arriving late this year. The Arctic Ocean become less cluttered with ice every year. Polar bears may one day not be able to reach the arctic and Hudson Bay ice from shore, thus their primary food source will be out of range. Polar Bears have already been measured to weigh significantly less than their grandparents of 30 years ago. Biodiversity is what makes a biosphere possible. The Earth's balance of nutrients and compounds such as CO2 were in sync with the plants and animals of the world. Three centuries ago, humans were at odds with Nature. Having enough food and firewood for the winter was literally a difference between life and death. Sprawl of urban areas, natural resource extraction and over-fishing are three instances of humans making a huge reduction in biodiversity. Estimates place the loss of species on Earth around 100 species a day are lost forever. That terms is difficult for many to fathom, especially those who continue to address the term endangered as if everyone were crying Wolf. The passenger pigeon will never fly again, even though descriptions from the 19th century say they flew in such thick flocks flying overhead would eclipse the sun. There are an estimated 10 to 30 million species on earth. We are loosing tens of thousands of species per year, many we will never know. Protecting endangered species is imperative. Many argue that the US's Endangered Species Act does not work because species are rarely kept off the list, however one can counter-argue that very few have gone extinct once on the list. Helpful Websites
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