Animals :: Environment, Natural Disasters, Extinction

We all studied the extinction of dinosaurs in middle school. We know that, two hundred fifty million years ago, more than 90% of the planet species became extinct. There have been five major mass extinctions during the life history of planet earth. Scientists now agree that we are experiencing a sixth major extinction. The big difference between the older events and now is, â€Å"unlike earlier extinctions, this one results from the work of a single species, Homo sapiens. We are relentlessly taking over the planet, laying it to waste and eliminating most of our fellow species† (Coyne 1). We should care about this man-made extinction for a lot of reasons, including the interconnectedness of life, our moral obligation to take care of our planet, and even economic factors. In the past, extinctions were caused by natural disasters, such as volcanic eruptions during the Permian period, and asteroid impact during the Cretaceous extinction. These major events caused global warming by increasing CO2 in the atmosphere, and shut down photosynthesis by blocking sunlight with a huge cloud of debris. Both of these catastrophes altered the Earth’s climate radically, which caused the extinctions (Campbell 521-522). The current extinction is not being caused by natural factors, but by us. â€Å"Rates of species extinction have increased rapidly since the early Holocene epoch, chiefly due to activities of humans; further acceleration of extinction rates began approximately 1600 AD, with the onset of accelerated human population growth and expanded scope of agriculture† (Hogan 1). We have caused this destruction by overfishing/hunting, destroying habitats, increasing global warming with fossil fuels and pollution, and a general disregard for the res t of the life on Earth (Coyne 1). For many years it was thought that humans had hunted the Wooly Mammoth to extinction. It has been found that â€Å"the wooly mammoth went extinct primarily because of habitat loss due to changes in temperature, while human hunting acted as the final straw† (â€Å"Climate Change and Human Hunting Combine To Drive The Woolly Mammoth Extinct† 1). Animals have been hunted for food, trophies, medicines, and souvenirs. Many of the endangered species are targets, such as the Chinese tiger, which has been hunted for medical use over the last 1000 years (Hogan 3). Overfishing has caused the populations of large fish to be only 10% of the levels found in 1950.