Biodiversity refers to the numbers and kinds of living things that exist in an area. About 1.5 million species have been identified. Scientists believe that there are many millions more species that have yet to be discovered. The largest group of known species is insects. Earth has three times more insects than plants.
Some areas are more diverse than others. An area is more diverse if it has a great variety of niches. Which has more niche diversity, a desert or a rain forest? You are correct if you said rain forest. Deserts are usually the same from area to area. A rain forest has layers upon layers of places to hide,hunt,eat,reproduce, and build nests.
Earth's most diverse ecosystems are along the equator. One of the reasons for this is that the climate is similar there all year long. Species have plenty of food, rainfall, and shelter. Plants are always growing and never shed their leaves. Organisms there don't have to survive harsh winter conditions.
Why is biodiversity so important? The higher the biodiversity in an ecosystem, the more stable it is. The loss of one species changes the way the other species interact. Species depend on one another. A disease that affects one species will have less effect on an ecosystem if there are many species.
Biodiversity also has a value as a source of recreation for people. People seek educational and adventurous ways to spend their leisure time. For example, they may hike through a rain forest to observe unique animals, such as the pangolin shown on the front of this card, in their natural habitats. This kind of tourism brings jobs to people.
Earth's biodiversity is a source of many products that people use.It provides people with food, medicines, and clothing. A cure for cancer may exist in the chemistry of an unknown plant in a rain forest.
Because the human population is growing so rapidly, we are crowding out other species. As people take up more space and use more resources, we destroy the habitats of other species. More species are going extinct because of habitat destruction today than even before. Global warming is a threat that is causing a change of climate for animals, such as the polar bear. The polar bear is a threatened species. This means that it will become endangered if something is not done to protect it. An endangered species is one whose numbers are so low that it is likely to become extinct.
Another threat to biodiversity is the use of pesticides or other chemicals. Pesticides are chemicals that people use to destroy organisms that are pests. These chemicals can also kill beneficial organisms. Chemicals can run off into streams and harm organisms that live there.
An introduced species is one that is not native to an area. Most introduced species have no natural predators, so they reproduce without limits. They can take over habitats and crowd out native species. A native species is one that is original and adapted to an area. The native species in an area can be completely wiped out by a successful introduced species. In Australia, the introduced of rabbits caused the extinction of many of the native species. The rabbits reproduced quickly and ate the grass that many of the native species needed for food. The native species were not able to survive alongside the rabbits, and many become extinct.
One of the most important ways people are protecting biodiversity is by preserving ecosystems. Our country and others have set aside national parks, refuges, and preserves. Private organizations have bought whole habitats> These areas are protected so that species can live and interact in their natural environments.