Question

What barriers have contributed to the establishment of zoographic realms worldwide?

Answer 1

Zoogeographic realms are formed by the dissimilar distributions of existing animals (normally illustrated by vertebrates), usually iso- lated geographically and defined by continents but sometimes separated by mountain ranges or other physiographic features.

The four main realms are:

Australian realms- Australia and nearby islands, with a preponder- ance of marsupials, large flightless birds, and par- rots, as well as an absence of mammals.

Oriental Realms-India and southeast Asia south through Indonesia, with tree shrews, orangutan, and gibbon

Ethiopian realms- Africa, though northernmost Africa is more simi- lar to Europe (Palearctic realm), with antelopes, giraffes, elephants, rhinoceros, gorillas, dogs, and cats.

Neotropical realms- South and Central America including the Carib- bean Islands, with sloths, armadillos, anteaters, tapirs, toucans, and hummingbirds.

Holarctic realms- the Holarctic realm includes most of the northern hemisphere, but is often subdivided into the Nearctic realm (North America south to central Mexico) and the Palearctic realm (Europe and Asia except for southeast Asia). The faunas of the Nearctic and Palearctic are really quite similar, with such animals as vireos, wood warblers, deer, bison and wolves.