3.8 Threats to Biodiversity Flashcards
(14 cards)
What is the result of overexploitation?
Populations can be reduced to a low level of genetic diversity but may still recover. Some species have a naturally low genetic diversity in their population and yet remain viable
What is the effect of the bottleneck effect?
Small populations may lose the genetic variation necessary to enable evolutionary change
In small populations, how can the loss of genetic diversity from the bottleneck effect be critical?
As inbreeding can result in poor reproductive rates
What is habitat fragmentation the result of?
The clearing of habitats
How is competition created through habitat fragmentation?
The degradation of the edges of the fragments makes them become smaller, increasing the competition and decreasing biodiversity
What kind of fragments exhibit a lower species diversity?
More isolated fragments and smaller fragments
How are widespread habitat fragments remedied?
They can be linked with habitat corridors
What do habitat corridors allow?
The movement of animals between fragments, increasing access to food and choice of mate
What does the movement of animals by habitat corridors lead to?
The recolonisation of small fragments after local extinctions
What is an introduced (non-native) species?
Those that humans have moved either intentionally or accidentally to new geographic locations
What is a naturalised species?
Those that become established within wild communities
What is an invasive species?
Naturalised species that spread rapidly and eliminate native species, therefore reducing species diversity
What are invasive species free from?
Predators, parasites, pathogens and competitors that limit their population in their native habitat
How might invasive and native species interact?
Invasive species may prey on native species, out-compete them for resources or hybridise with them
