Role Of Extinctions Flashcards
Define extinct.
No member of the species remains alive anywhere in the world e.g. Dodo.
Define ‘extinct in the wild’.
Individuals remain alive only in captivity or other human-controlled situations, e.g. Black-footed ferret.
Define ‘globally extinct’.
Extinct in the wild across its entire range e.g. The Franklin Tree.
Define ‘locally extinct’.
No longer found in an area it once inhabited but is still found elsewhere in the wild e.g. Lynx in Scotland.
Define ‘ecologically extinct’.
Persists at such reduced numbers that its effects on the other species in its community are negligible, e.g. Tigers.
What is the ‘Anthropocene extinction’ and when did it begin?
Thought to be the current mass extinction we are going through. Some believe the late eighteenth marks the beginning of this due to high concentrations of methane and CO2 found in polar ice from the industrial revolution. Others suggest earlier dates.
What is the background extinction rate?
1 - 0.1 species extinctions per million years.
When was the biggest mass extinction?
Permian.
In what period did the dinosaurs go extinct?
Cretacious.
Give examples of human-induced extinctions.
- Extinction of many Megafauna in Austrailia and North and South American due to hunting.
- Extinction of many bird species in the Pacific islands due to colonisation of Polynesians.
Give examples of extinct animals native to Australia.
- Pig-footed Bandicoot
- Broad-faced Potoroo
- Thylacine.
How do current extinction rates compare with the natural background rate?
100-1000 times greater.
What areas are prone to extinction?
Islands and endemic rich areas.
What is the species-area curve equation?
S = cA^z
S is number of species present.
A is area.
c and z are constants.
For taking logs,
LogS = logc + ZlogA.
Which is a straight line of slope z.
Can we estimate extinction rates from habitat loss?
Maybe. More research is required.
