1 Biodiversity refers to the numbers 7 Because the human population is
and kinds of living things that exist in an growing so rapidly, we are crowding out
area. About 1.5 million species have been other species. As people take up more
identified. Scientists believe that there are space and use more resources, we destroy
many millions more species that have yet to the habitats of other species. More species
be discovered. The largest group of known are going extinct because of habitat
species is insects. Earth has three times destruction today than ever before. Global
more insects than plants. warming is a threat that is causing a
2 Some areas are more diverse than change of climate for animals, such as the
others. An area is more diverse if it has a polar bear. The polar bear is a threatened
great variety of niches. Which has more species. This means that it will become
niche diversity, a desert or a rain forest? endangered if something is not done to
You are correct if you said rain forest. protect it. An endangered species is one
Deserts are usually the same from area to whose numbers are so low that it is likely to area. A rain forest has layers upon layers become extinct.
of places to hide, hunt, eat, reproduce, and 8 Another threat to biodiversity is the use
build nests. of pesticides or other chemicals. Pesticides
3 Earth's most diverse ecosystems are are chemicals that people use to destroy along the eq_uator. One of the reasons for organisms that are pests. These chemicals this is that the climate is similar there all can also kill beneficial organisms.
year long. Species have plenty of food, Chemicals can run off into streams and rainfall, and shelter. Plants are always harm organisms that live there.
growing and never shed their leaves. 9 An mtroduced species is one that Organisms there don't have to survive harsh is not native to an area. Most introduced winter conditions. species have no natural predators, so they
4 Why is biodiversity so important? The reproduce without limits. They can take higher the biodiversity in an ecosystem, the over habitats and crowd out native species. more stable it is. The loss of one species A native species is one that is original and changes the way the other species interact. adapted to an area. The native species in pedes depend on one another. A disease an area can be completely wiped out by a that affects one species will have less effect successful introduced species. In Australia, on an ecosystem if there are many species. the introduction of rabbits caused the
5 Biodiversity also has a value as a extinction of many of the native species.
source of recreation for people. People seek The rabbits reproduced q_uickly and ate educational and adventurous ways to spend the grass that many of the native species their leisure time. For example, they may needed for food. The native species were hike through a rain forest to observe uniq_ue not able to survive alongside the rabbits, animals, such as the pangolin shown on the and many became extinct.
front of this card, in their natural habitats. 10 One of the most important ways people
This kind of tourism brings jobs to people. are protecting biodiversity is by preserving
6 Earth's biodiversity is a source of many ecosystems. Our country and others have products that people use. It provides people set aside national parks, refuges, and
with food, medicines, and clothing. A cure preserves. Private organizations have
for cancer may exist in the chemistry of an bought whole habitats. These areas are unknown plant in a rain forest. protected so that species can live and
interact in their natural environments.