chapter 10 march 26 th, 2012. faunal regions floral regions floral & faunal biogeographic...
TRANSCRIPT
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