Global Issues Flashcards
Define background extinction
When a species naturally fades away over time because they cant keep up with environmental change
Define mass extinction
When extinction rates rise suddenly due to a major disturbance to the planet
What are the 6 main causes of the current biodiversity crisis?
- habitat destruction
- hunting and fishing
- overfishing
- competition from invasive species
- pollution
- climate change
What are the 7 categories in which the IUCN splits endangered species into?
- least endangered
- near threatened
- vulnerable
- endangered
- critically endangered
- extinct in the wild
- extinct
What does EDGE species stand for?
Evolutionary Distinct, Globally Endangered
Define evolutionary distinction
A measure of how unique or unusual the genome of species is
Explain how evolutionary distinction works
- some species are unique and have ancestors that branched off of the evolutionary tree millions of years ago so don’t have any species that share a similar genome ; by losing these, we’d lose irreplaceable genetic diversity
- some species formed their own branch on the evolutionary tree so have a cousin species that share a very similar genome to them
How does EDGE species help us prioritise which species to save?
- EDGE species are species which are both genetically unique and highly threatened
- most species usually are either one or the other, so it’s the species that have both of these qualities that we must focus on
- it’s an efficient way of saving the maximum genetic diversity with limited resources
Define flagship species
A species selected as a mascot, ambassador, icon or symbol for a defined issue, campaign or environmental cause
What are the common features that most flagship species share?
- they are large
- they are mammals
- they are cute and fluffy
Why does the appearance of an animal preside over its usefulness to its ecosystem? Why is this bad?
- people are more likely to donate money to a more physically appealing animal that may not be useful to its ecosystem rather than an ugly one which does
- this is bad because more money is donated to animals which may not help their ecosystem than to those which do
What is the compromise for flagship species in order that keystone species can be saved?
- flagship species can be used as an ‘umbrella species’ offering protective canopy to more ecologically important species
- e.g if money is invested to Chinese forests where pandas live, then all the important species of the area will also receive some money
Define keystone species
A speceis considered to be vital to the health of the ecosystem ; if we were to lose that species then the whole ecosystem would collapse, resulting in the loss of even more species
How do tiger sharks help their ecosystem?
- patrol the seabed in search for turtles
- when tiger sharks aren’t around, turtles graze seagrass in safety, to such an extent that it’s destroying it
- this means that no other species can live in the area
- tiger sharks keep their numbers in check , ensuring other species remain protected
How do beavers help their environment?
- take old/dead trees to make their river dams, allowing new tree growth
- by creating dams, surrounding areas are flooded and form wetlands, creating new habitats for species
