Biogeography Flashcards
What geographical region has the most families? least?
Ethiopian = 52 Australian = 28
Which geographical region has the most endemic families? least?
Neotropical = 22 Paleartic = 0
What abiotic processes influence biodiversity?
temperature
precipitation
sunlight
wind
sequence of events of continental drift?
- triassic period = pangaea
- jurassic period = pangaea divides into Laurasia and Gandwanaland
- End of Cretaceous = S.Amer drifts westward breaking from Africa
- Cenozoic Era = continued drift yielding current continental spatial arrangement
Biotic processes of biodiveristy
dispersal -ecological vs species -passive vs active animal movements faunal interchange extinction diversification
The Great American Interchange
many animals were able to pass through mexicoish areas
Island rule
insular gigantism vs insular dwarfism
on islands, small animals are bigger and big animals are smaller
insular gigantism
gigantism
- immigrant selection
- intensified intraspecific competition
- ecological release from lg competitors/predators
insular dwarfism
- ecolgocial release from predators
- intensified infraspecific competition
- resource limitation and specialization
Bergmann’s rule
larger body size with increasing latitude
- overall supported by not really for small-bodies mammals
- SA:V ratio
Allens rule
shorter appendages in colder climates
Rapoport’s rule
species ranges are larger in higher latitudes
- experience greater range of climatic variability
- tropics: more stable climate
Gloger’s rule
coloration difference in pelage
- darker in drier habitats = thermoregulatory adaptations
- predator avoidance = dorsal pelage colour and soil colour in rodents
reason for latitudinal gradient in mammals?
more species in tropics vs arctic
land availability
“out of tropics model”
start in tropics bc its favourable
elevational gradient in mammals?
decrease in species from low to high elevations
sometimes peak at middle
lack of competition so they move up to moreso unfavourable habitats
