Bald Eagle

Common in 1700s and 1800s 1900s- decline in population

Farmers Toxic chemical waste

Health of top-level carnivores indicates whether toxins are entering an ecosystem

COSEWIC Committee On the Status of

Endangered Wildlife In Canada Assesses and designates which wild

species are in danger of disappearing

http://canadianbiodiversity.mcgill.ca/english/species/endangered/extinct.htm

Classifying Species at Risk Extinct Extirpated Endangered Threatened Special Concern

Extinct

Species that is no longer found anywhere

Example: Great Auk QC, NB, NS, NL Over-hunting Extinct since 1844

Extirpated

Species that no longer exists in one area but can be found in others (Locally extinct)

Example: Grizzly Bear No longer found in the

Canadian prairies Hunting and habitat

destruction

Endangered

Species that is close to extinction in a significantly large location

Example: Beluga Whale Arctic and Atlantic Ocean Over-hunting Habitat Degradation

Threatened

Any species that is likely to become endangered if things are not reversed

Example: Killer Whale Pacific Ocean Decrease in prey (salmon) Physical and Accoustical

Disturbances Oil spills and contaminants

Special Concern

Species that are particularly sensitive to human activities or natural events

and could become endangered or threatened Example: Polar Bear

YT, NT, NU, MB, ON, QC, NL, Arctic Ocean

Overharvest Climate Change

SARA

Species at Risk Act Established in 2003 Purpose is to protect wildlife species

at risk in Canada. Government must legally protect

species designated by COSEWIC.

Extinction in Modern World Extinction rates are increasing Causes?????

Mostly human activities

Mass extinction occurred before humans Caused by major catastrophes Example: Yucatan Peninsula- Asteroid

Effects of Extinction Biodiversity- number of species in an

ecosystem

“Domino Effect”- Removal of one part can cause the collapse of the entire food chain.

Example: over-hunting of sea otters Sea urchin population increased led to destruction of kelp beds

What is our role?Restoring the Balance

Once an ecosystem is damaged, should it be fixed?

Example: Petitcodiac River Example: Wolves of Yellowstone National

Park Example: Peregrine Falcons in NB