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a measure of how many species are in an area
why maintain biodiversity?
How does ecosystem services that help maintain biodiversity?
to purify our air and water (phytoplankton)
to reduce floods (vegetation)
to generate fertile soil
to cycle nutrients
to protect from erosion
to control agricultural pests
Why do we need species?
sources of medicines!
provide us with recreation!
ecotourism =giving $$ to a country to view their environment
contain genetic info that tells the story of earth!
# of species?
- 1.3 million catalogued
- ~8.7 +/- 1.3 million
- undiscovered: insects fungi, bacteria
species that have few individuals and is near becoming endangered
examples of threatened species
- Northern Spotted Owl (threatened species)
- Habitat loss in Canada & No. US
- Need old growth forest, top predators and are specialists
species that can only thrive in a narrow range of environmental conditions or has a limited die
species that have fewer individuals
at risk of becoming extinct
examples of endangered species
scavenger birds; eats dead carcasses
2005 = 273 individuals
endangered= low birth rates, late sexual maturity, poaching, lead poisoning, DDT and power lines
Case Study: California Condor
Intrinsic characteristics of Extinct Species
extremely localized/ require LARGE territory
low birth rates
island species/ extreme specialists
late sexual maturity
species no longer exists on earth
examples of extinct species
Dodo birth, Tecopa Pupfish
- Yangtze River Dolphin aka Bajii (last sighting in 2004)
- causes: heavy transportation on river, overfishing of their food, dams, collision with boats, H20 pollution
200 years ago -> 3 ~ 5 billion
was the world's most abundant bird
1 flock =10 mi wide, 100 mi long
they were killed for its meat
Martha died in 1914
Case Study: Passenger Pigeon
3 - 30 species die/ year caused by natural selection
1000's species die/year
caused by dramatic environmental change
5-6 so far
human causing 6th? (previous mass extinction
Root causes of extinction?
too many people!
weak/ no laws
high consumption rates
humans causes extinction
habitat loss/habitat fragmentation
capture & sale of exotics (2.5 million birds caught illegally/yr 1 bird = 10 deaths in transits)
introduction of non-native species (species that does not belong in area)
example of introduction of non-native species
ice plant @ beach
how does non-native species cause problems with native species?
can usually out-compete natives
eat some food resources as native
no natural predators in new area
reproduce with no limits on growth