Biodiversity Flashcards
What happens to biodiversity after an extinction event and why?
Gradually increases as survivors undergo speciation and adaptive radiation (due to newly available niches)
What are the measurable components of biodiversity?
Genetic diversity, species diversity, ecosystem diversity
What is species diversity?
The species richness – number of different species
The relative abundance – proportion of each species present
What is genetic diversity?
Number and frequency of alleles present in a population
What is the bottleneck effect?
When a large percentage of population is lost leading to reduced genetic diversity of survivors.
Which factors can affect biodiversity of an island?
Size of island
Distance from mainland
How does habitat fragmentation affect biodiversity?
Leads to reduced habitat area so reduced resources. Lowers biodiversity as species have to compete for resources
Why is a high edge to interior ratio a problem in habitat fragments?
Forces edge species into interior to compete for resources which can lead to extinction of interior species.
Why are habitat corridors used?
To join habitat fragments allowing members to colonise an area and to mate.
What is meant by an introduced species?
Foreign species moved intentionally or accidentally into a new area.
What is meant by a naturalised species?
Foreign species who are able to survive and reproduce in their new habitat.
What is meant by an invasive species?
Foreign species who reproduce rapidly and outcompete with native species
Which factors allow introduced species to become invasive?
Removing organisms from environment faster than they can be replaced by reproduction.
What is meant by overexploitation?
Removing organisms from environment faster than they can be replaced by reproduction.
