This is a measure of the number of different organisms in a habitat. Across the planet levels of biodiversity are reducing because of human interference.
"Know that biodiversity can be assessed at different scales: (a) within a habitat at the species level using a formula to calculate an index of diversity; (b) within a species at the genetic level by looking at the variety of alleles in the gene pool of a population."
This is the variety of organisms living in a habitat.
Variation in a Habitat
The larger the index, the greater the diversity.
- Species richness - the number of different species within a community. This does not account for the number of each.
- Species diversity - takes into account the number of individuals of each species. An index can be found using the following formula:
- D = [N(N-1)] / [Σn(n-1)]
- N = number of all organisms of all species
- n = number of individuals of each species
Variation in a Species
Within a species all organisms have the same gene pool. However, each organism may have a different combination of alleles. This results in genetic diversity.
Understanding biodiversity allows conservation efforts to be well informed and effective.
Why Maintain Biodiversity?
"Understand the ethical and economic reasons (ecosystem services) for the maintenance of biodiversity."
There are a number of reasons why levels of biodiversity should be increased or maintained. Reasons include:
- More stable populations
- More resilient populations (more alleles allows populations to adapt more easily)
- Loss of keystone species could have severe negative impacts
- Pleasant to look at
- Ecotourism opportunities
- Provide goods and sources of medicine
- Stabilise soils
- Increase the gene pool further increasing the ability of a population to adapt
"Understand the principles of ex-situ (zoos and seed banks) and in-situ conservation (protected habitats), and the issues surrounding each method."
This is to preserve something, keeping it in its natural state.
This is conservation within the natural environment. Methods can include restoration and legislation.
|Protects more than one species
||Hard to enforce any legislation
||Some areas need extensive work
|Fewer facilities required
||Populations may still decline
|Can conserve unknown species
This is the conservation of plants and animals outside of their natural habitat (zoos and seed banks).
||Cannot fully recreate a natural habitat
|Require less space
||Disease can quickly spread
|Inter-zoo exchange maintains genetic diversity
These are an example of ex-situ conservation. Animals are placed into an artificial habitat and usually enter a captive breeding programme.
There has been limited success so far and many feel it is unfair to keep animals in captivity.
|Educate the public
||When reintroduced into the wild animals can lack survival skills
|Zoos can carry out research
||Limited success seen so far
|Increase population numbers
These play a major role in storing and conserving genetic diversity. Seeds are stored in dry, cold conditions to keep the seeds viable. The process of seed collection is outlined below:
This allows for future repopulation if necessary.
- Seeds collected
- Tested for viability
- Cleaned & sterilised
- Routinely checked for viability
- If required seeds will be replaced