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For valuing biodiversity, what are the two types of values and what are the differences between them?
- Extrinsic: consumptive (harvested) and non-consumptive (not destroyed/harvested)
- Intrinsic: nature has value in and of itself, important because purely extrinsic reasons could lead to the protection of species believed to be of higher value.
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3 types of extinction
- 1. Local/Extirpation: extinct in a specific area.
- 2. Ecological: too few to fulfill its role in the ecosystem.
- 3. Biological: gone forever
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Examples of Ecologically extinct animals
mountain lion, great hornbill
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What are the direct causes of the depletion of wild species?
- Habitat loss (loss of niche)
- Habitat degradation (quality going down due to pollution) and fragmentation (large forest split by road)
- Introduction of nonnative species (invasive species)
- Pollution (biocides)
- Climate change (biomes retreated further north because temp and rainfall is changing)
- Overfishing
- Commercial hunting and poaching
- Sale of exotic pets and decorative plants
- Predator and pest control
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What do human activated pressures lead to?
- small, fragmented, isolated populations
- inbreeding (limited gene pool) which leads to diseases, vulnerability
- demographic instability
- decline in population
- extirpation or extinction
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Overharvesting is the major cause of endangerment of
marine species
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Case Study: The Passenger Pigeon
- From numerous to extinct in 100 years
- Uncontrolled hunting
- good to eat
- Feathers made good pillows
- Bones used as fertilizers
- Easy to kill as they flew in gigantic flocks (blocked out the sun)
- nested in long narrow colonies
- Habitat loss to new human settlements
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List the COSEWIC's risk categories in increasing order or danger
special concern, threatened, endangered, extirpated, extinct
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Examples of species that were subject to predator control
- Carolina parakeet - damaged fruit crops
- Prairie Dogs poisoned to save cows and horses from breaking their legs. Led to decline of black-footed ferret.
- Deer to reduce over-browsing of vegetation
- Wolf on Vancouver Island to increase deer for hunters
- Coyotes in Newfoundland to increase Caribou
- Seals to protect cod
- Cormorants in Lake Erie to protect endangered plants
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What is the number one reason responsible for what percent of species listed as endangered in Canada
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What types of changes do human demands cause?
- 1. Physical changes: removing important, tangible habitat components (deforestation)
- 2. Chemical changes: degrading habitats so it can't support wildlife (biocides)
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How much of the world's wetlands does Canada contain?
1/4
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Where are the Carolinian forests? Why are they important?
- ecozone in southwestern ON
- support greatest wildlife diversity in Canada
- 40% of animals listed under SARA in this zone
- remaining tracts belong to regional conservation authorities and private landowners
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What was the cause of extirpation of Bald Eagles from the Great Lakes region?
pesticide biomagnification of mercury and lead
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What is the first and second leading cause of endangerment (%s)
- 1. Habitat Loss 84%
- 2. Invasive Alien Species 40%
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What are the characteristics that make species vulnerable to extinction?
- specialized habitats
- migratory species
- limited and local distributions
- valuable species (economic value)
- large body size (Vulnerable to disruption of prey species and bioconcentration; hunted more easily)
- need a large home range
- Small population size
- Not effective dispersers
- Behavioural traits causing susceptibility (flying in front of cars, manatee attracted o motorboats)
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