Just as it is difficult to imagine the wide range of the extinction problem, it is also hard to determine exactly how many species have already died off. Because we know so little about the variety of life on Earth, it is likely that many species have died out without our knowing. Scientists estimated that about three species die per day. Today s massive and rapidly growing human population is capable of much greater damage. As population increases more species decreases.
Human beings are the sole species, which are able to cause a mass extinction of many other species.
Human activities, including the clearing of forests, the spread of agriculture, illegal hunting for animals under protection, the pollution of water, air, and soil caused the extinction of the last several thousands of years. As I motivated above if the human population grows and human activities increase, the problem will become more serious. More people require more food and more space to live, and they create more waste. Beside our experiments we should not forget that we are the sole species who are able to save others. The existence of animals has several important advantages.