5.2 extinctions and protecting species
extinctions
biodiversity
extirpation
permanent
not increased by evolution
increased by speciation
decreased by extinction
local, not worldwide extinction
5-10m yrs to replace extinct species
background extinctions:not caused by humans
rate: 1 species/1yr/1 million
99.9% of species that have existed are extinct
species only lives up to 2-10 million yrs
general speciation:background extinction rate is higher
mass extinctions
5
geology,fossils
50-90%of species present at time went extinct
paleozoic
mesozoic
ordovician
devonian
contemporary
permian
triassic
cretaceous
present, human induced extinction
possible causes (post human)
sustained and significant global warming/cooling
large changes in sea levels/ocean water acidity
catastrophes as multiple large scale volcanic eruptions
large asteroids/comets
competition from new migrated species
human induced extinctions
extinctions rates increased with population growth
species going extinct 100x faster than prehuman times
vulnerable species
k strategists
dont breed often
specialists
high trophic levels
live in small range
commercially valuable
can be wiped out by catastrophy
decorative, medicinal
island species
protection treaties and laws
IUCN Red List
classifying species at high risk of global extinction
Convention on International Trade in Endangered Species of Wild fauna & flora (CITES)
bans hunting, capturing, selling of endangered species
Convention on BioDiversity
reduce rate of extinction by focusing on ecosystems and sustainability on global scale
USA didnt sign
no way of enforcing laws
US endangered species act (ESA)
identify and protect endangered species in USA
protect critical habitats by prohibiting land that would damage it
penalties of high cost
inspection of shipments of animals
wildlife refuges
560 in National wildlife refuge system
wetlands
protecting species ex situ
seedbanks and botanical gardens
preserve genetic info and seeds of endangered plants
wildlife farms
breeding reduces hunting
zoos and aquariums
animal research centers