3.8 Threats to biodiversity Flashcards
Exploitation
Where humans deplete natural resources and use them to benefit themselves.
Over exploitation
Where humans deplete natural resources and use them to benefit themselves, to the extent where they reduce populations of organisms to a low level.
Outcomes of over exploitation
The population can either recover or go extinct.
Do all species have to have high genetic diversity
No - some species can have low genetic diversity and still be viable.
The bottleneck effect
Where an event drastically reduces the size of a population in an ecosystem and can alter the future genetic diversity of the population
Bottleneck events examples
Natural disasters
Over hunting
Habitat destruction - damaging the habitat beyond repair so all the organisms there die.
How does the bottleneck effect damage small populations
The bottleneck event can kill off genetic diversity, meaning the population loses variation and can’t respond to changes in the environment.
Habitat fragmentation
Where large areas of a habitat are cleared out, breaking the habitat down into smaller habitats.
Bottleneck stages
Original
Bottle neck event
Surviving population
New population
Consequences of habitat fragmentation
Increase competition
Decrease biodiversity
Relationship between fragment size and biodiversity
As the fragment size decreases the biodiversity decreases.
Relationship between isolation of fragments and biodiversity
As the isolation increases the species diversity decreases.
Internal habitat and edge of habitat differences
Internal has high biodiversity
External edges have lower biodiversity and life abundance.
Habitat corridors definition
Links between habitat fragments, used to improve depleted biodiversity and decrease habitat fragmentation.
Advantages of habitat corridors
Allows animals to move between different habitat fragments
Allows for recolonisation of local extinctions
Increases access to resources and mates.
