Chapter 10

March 26th, 2012

Faunal regions

Floral regions

Floral & faunal biogeographic

regions

Wallace’s Line

• Biogeographic line – a line dividing biogeographic realms

Evolution of Mammals

• Mammals first appeared 220 mya

• Small in size; egg layers

• Small size and warm-blooded physiology allowed some mammals to survive KT Extinction

• Adaptive radiation occurred as mammals evolved to fill the many vacant niches caused by the extinction of the dinosaurs

Marsupials and Placentals

• Angiosperms – flowering plants– Unknown origin– Many primitive living angiosperms in the

South Pacific region– Between 100 mya and 65 mya angiosperms

increased from 1% to over 50%

• Gymnosperms – naked seed– dominate where they can outcompete

angiosperms– Disputed origin – first appeared 365 mya– Spruce 159-180 mya; Pine 144-99 mya

Modern Biogeographic Regions• Nearctic + Palearctic = Holarctic• Nearctic = North America, Greenland, and most of

Mexico– 13 families of terrestrial mammals– 111 genera of placental mammals– 94 native angiosperm families– Cacti– Horses, camels

• Palearctic = Europe, northern Africa, and northern Asia– 18 families of terrestrial mammals– 69 native angiosperm families– Bears, buffalo, moose, caribou, polar bear

• 21 shared species of mammals• Different glacial histories

• Neotropical Region – South and Central America and adjacent islands– 23 families of terrestrial mammals– 200 species of endemic rodents– Second highest diversity of marsupial

mammals– Most diversity in flowering plants– Cacti– Great American Interchange led to high

extinction rates of Neotropical marsupials

Modern Biogeographic Regions

• Ethiopian (African) Region – Sub-Saharan African and parts of Arabian Peninsula– Most diverse mammal fauna– Diverse angiosperm flora– Elephants, mammoths– Similarities in flora with Australian and

Neotropical Regions– Similarities in fauna with Palearctic

Modern Biogeographic Regions

• Oriental Region – Indian subcontinent and adjacent south Asia– 20 families of terrestrial mammals– 108 families of angiosperms– Contains tropical vegetation from Australian,

Ethiopian, and Neotropical Regions– Contains montane vegetation from Holarctic

Modern Biogeographic Regions

• Australian Region – Australia, Tasmania, New Guinea, and New Zealand– Marsupials– Bats only native placentals– 10 families of terrestrial mammals– 18 families of angiosperms– Crows, ravens, magpies

Modern Biogeographic Regions

WombatTasmanian devil

Extinct marsupial lion

opossum

Marsupials

Monotremes• Egg-laying mammals

• Have cloaca – serves as anus, urinary tract, and reproductive tract

• Animalia, chordata, mammalia, monotremata

PlatypusSpiny anteater