ESS Standard Topic 3.1

Genetic diversity

The range of genetic material present in a gene pool or population of a species

Species diversity

A product of the number of species (richness) and their relative proportions (evenness)

Habitat diversity

The range of different habitats per unit area in a particular ecosystem or biome.

Examples of Habitat Diversity

• The layering of rainforest allows for many niches to exist and therefore more species can co-exist. 

• The mix of vegetation, rocks and water create many habitats within one ecosystem. 

Importance of biodiversity

Ecosystems are more resilient when they have a higher biodiversity

Resilience

The ability of an ecosystem to avoid tipping points and cope with change.

Evolution

The gradual change in the genetic character of populations over many generations

Natural selection

The mechanism of how evolution happens:

1. Variation 

2. Overproduction 

3. Competition 

4. Survival 

5. Reproduction

6. Repeat over long time

Speciation

When new species arise from existing ones. This is the result of isolated reproductivity from the rest of the species for several generations, so they evolve differently

Example of speciation

• In the Arizonian grand canyon there are two separate squirrel species. On the south the harrisi and on the North the leucurus, due to the populations being separated.

• Continental drift (Antarctica used to be a rainforest)

• Land bridges joined S & N America – shrimp now separation by land

• Separation of the Gondwana the super continent (Southern hemisphere)