Many years ago there was a bird, the passenger pigeon that was very plentiful.
When the flocks would fly, they covered the sky and nearly blocked out the sun.
People killed them, not for food, but for fun. They thought the bird would be here
forever. The last passenger pigeon died in a zoo in 1914. Black bears were abundant
in New Jersey. In the mid 1970's, they were nearly driven to extinction. Laws were
passed and the bear have made a comeback. When humans have taken actions that
harm the planet and the creatures living within it, the government must take action.
That is the case with the extinction of plants and animals. Why should they go
Over 34,000 plant species and 5,200 animal species around the globe are
threatened with extinction, and many thousands more become extinct each year
before biologists can identify them. The primary causes of species extinction or
endangerment are habitat destruction, commercial exploitation, damage caused by
nonnative plants and animals introduced into an area, and pollution.
causes, direct habitat destruction threatens the most species. As species evolve, most
adapt to a specific habitat or environment that best meets their survival needs.
Habitat disintegration has caused plant and animal species in the remaining islands
of habitat to lose contact with other populations of their own kind. This reduces
their genetic diversity and makes them less adaptable to environmental or climatic
change. These small populations are highly vulnerable to extinction. Since the 1600s,
worldwide commercial exploitation of animals for food and other products has
caused many species to become extinct or endangered. Wildlife trade involves the
capture of animals for pets, zoo specimens, and research subjects. The capture of
wild animals for commercial use has endangered many species. Other animals have