Chapter 10 March 26 th, 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 mya; Pine 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

Wombat Tasmanian devil Extinct marsupial lion opossum Marsupials

Monotremes Egg-laying mammals Have cloaca – serves as anus, urinary tract, and reproductive tract Animalia, chordata, mammalia, monotremata Platypus Spiny anteater