3.8 Threats to Biodiversity Flashcards
What is the difference between exploitation and overexploitation?
Exploitation is the act of exploiting an ecosystem for personal benefit.
Over exploitation is exploitation where the individuals are being removed faster than the reproduction rate.
Why do small populations have poor reproductive rates?
Lack of genetic variation and <strong> inbreeding </strong>
Describe the bottleneck effect
Bottleneck effect is where a density independent factor wipes out a population leaving a few individual survivors who have very low genetic diversity
What is the effect of bottleneck effect on populations?
It leaves the survivors with low genetic diversity meaning they do not have not the variation to adapt to environmental change
Give an example of a population who were nearly drove to extinction by over exploitation
Cod
What are some human causes of habitat fragmentation?
Deforestation
Urbanisation
Building of Roads
Describe ‘Habitat Fragmentation’
Habitat is broken up into fragments by geographical processes or human activity
What happens when the edges start to erode in a habitat fragment?
Edge species invade the habitat middle at the expense of interior species.
What is a solution to habitat fragmentation/
Using Habitat corridors to relink ecosystems
Define ‘habitat corridors’
Area of habitat connecting previously separated populations
What do habitat corridors allow for?
Allow species to feed, mate and recolonise habitats
Define an introduced species?
Species that has been moved either intentionally or accidentally to a new geographic location
What is a <em>‘Naturalised’</em> species?
A species that has became established within wild communities
Define an ‘Invasive species’?
An invasive species is a species that spreads rapidly and eliminate native species
Why do some naturalised species become invasive?
- Free of natural predators
- Free of competition
- Free of pathogens or parasites
