Class Notes (806,513)
Canada (492,267)
ENV200H1 (48)
Karen Ing (37)

Env 200 mar 12 lec 14.docx

3 Pages
Unlock Document

University of Toronto St. George
School of Environment
Karen Ing

Env 200 mar 12 lec 14  Extinction o Death of a life form o Natural event o Fate of all species o 99% of all previous species are extinct o Currently accelerated by human activities  100-1000 times natural rate  Se fig 7.6 p 209  Species at risk o Extinct: no longer present anywhere o Extirpated species: no longer present in wild o Endangered species  Facing imminent extinction o Threatened species  High probability of becoming endangered o Special concern  Not in serious danger, but sensitive to human activities o Genetic variability severely diminished  Human-caused reductions in biodiversity o Increasing wealth (based on exploiting the env) is generating demands on the env that cannot continue to be met o In the poorer regions of the world poverty forces ppl to adopt subsistence living (ex: deforestation and overgrazing) that destroys critical habitat for other species  Human causes of species endangerment o Habitat loss o Pollution o Overexploitation o Invasive species  Habitat loss o Largest threat to species o Destruction, fragmentation, degradation  As we fragment habitat, we leave small islands of undisturbed habitats in a sea of disturbance  Mac Arthur and Wilson’s Theory of Island Biogeography o 1. Distant islands support fewer species than near shore islands (distance effect) o 2. Larger islands support more than species than small islands o 3. Larger islands have lower extinction rates  Pollution o Acid precipitation o Ozone depletion o Climate change o Direct/indirect poisoning o Altered habitat from chemicals  Overexploitation o Hunting and fishing  Over harvesting of game species  American passenger pigeon  American bison  Whales  Atlantic cod o Endangered species consumption ex: whales sharks dolphins chimps (bush meat) o Commercial harvest  Zoos, laboratories, pet stores  Many die in transit, including plants, wildlife smuggling etc  Predator and pest control o Many animal pop have been greatly reduced or exterminated b.c they’re regarded as dangerous to humans or livestock  Birds, coyotes, wolves,
More Less

Related notes for ENV200H1

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.