The human species is threatening the very existence of many other life forms. As the human population develops, more and more of the earth’s living space, food, and other resources are used up. Many species are threatened with extinction within a period of time that is shorter than ever before.

Why should we bother about endangered species? One reason is that many, especially plant species, may contain substances which could be useful to all mankind, as the basis of new drugs for example. When other species are disappearing, it is actually affecting our life as well. Different life forms interact with one another to support and sustain the balance of nature. A lot of the daily necessities for the support of human existence like food, medicine, clothing and shelter come from plants and animals. Human populations depend a lot on the existence of these creatures. Perhaps even more important, integral ecosystems perform many important functions, like purifying the air, filtering harmful substances out of water, turning decayed matter into nutrients, preventing erosion and flooding and moderating climate. If any species is stamped out from an ecosystem, the functioning of this system will be weakened. At first, wildlife laws were passed to control exploitation of animals that people hunted. Now, other than animals we value for food or other uses, we are also aware of the importance of animals that have little or no immediate economic value. It is only recently that people have become alarmed about the decline of wildlife that has no commercial value to them.

Never before have human factors affecting species so much in history. One major cause of wildlife endangerment is habitat loss. Plants and animals, like humans, need space to live and food for energy. As human population and consumption of nature’s resources grow, the homes for wildlife are changed into houses and roads. Trees are cut down for building materials, fuel, and paper. Grassland and forests are converted into farm land and grazing land for our livestock. We have commercial buildings and residential blocks in places where wetlands once existed. To created hydropower, river dams are built but this has caused river valleys to flood and ocean-going fish find it difficult to migrate to the sea. Many species need large areas of habitat to survive and reproduce. The disappearance of forests and grasslands quickens the extinction rate of wild life. Even if habitats are not completely destroyed, they can be fragmented or degraded so much that they can no longer support wildlife they once did.

Human activities also had lead to the decline of wildlife. These include capturing or hunting animals for human use. Animals are killed for food, fur, feathers, oil, medicines, crafts, and many other uses. Sometimes people shoot them to stop them from killing livestock and sometimes just for pleasure. Animals are captured for pets, for medicinal use or for scientific testing. Even their eggs are taken for food. Advanced technology makes it possible to capture large numbers of animals at one time and this has contributed to the quick extinction of seemingly boundless species like ocean fish. As the wealth of developing countries increases, the demand for animals products grows. The international market for animals and animal products is bringing the endangered species to the brink of extinction.

One cause that leads habitats to be degraded is pollution. Creatures that depend on either freshwater or seawater for all or part of their life cycles, like fish, frogs and marine animals are especially at risk. Water is polluted by flowing of fertilizers and pesticides from farms, oil and other chemicals from roads, and untreated sewage that runs into rivers, lakes, and oceans. In addition to polluting waterways, fresh water from rivers and lakes in diverted for irrigation, drinking water, and industrial uses. There is less water left in the rivers and lakes to weaken the pollutants. Ships pollute seawater by pumping waste into it. Oil spills kill large numbers of animals. Besides water pollution, factories and cars also release exhaust fumes into the air. The chemicals in these fumes are deposited on land by rain, causing pollution. This is know as acid rain. Acid rain is harmful to plant life, and thus limiting the food supply for animals that eat the plants. Furthermore, farmers use pesticides which are another source of pollution to keep insects from eating crops. These chemicals remain in crops and in wild plants eaten by other plant-eating creatures. Insects also carry pesticides. Animals that eat these plant-eating creatures and insects get high concentrations of these pesticides in their bodies. The chemicals can upset biological functions like reproduction in these animals and in the end accelerate the extinction rate of wildlife.