Why are there endangered species ?

Habitat DestructionSpecies become extinct or endangered for a number of reasons, but the primary cause is the destruction of habitat. Man has seriously reduced available habitats byDrainage of wetlands conversion of shrub lands to grazing lands cutting and clearing of forests (especially in the Tropics, where the rain forests will be gone by AD 2000 if destruction continues at its present rate) urbanisation and suburbanisation highway and dam construction.As the various habitats become fragmented into "islands," the remaining animal populations crowd into smaller areas, causing further habitat destruction. Species in these small islands lose contact with other populations of their own kind, thereby reducing their genetic variation and making them less adaptable to environmental change. These small populations are highly vulnerable to extinction; for some species, the fragmented habitats become too small to support a viable population.