4.2.1 Biodiversity

Question 1

What 3 levels can biodiversity be assessed at?

Answer 1

Numbers of and ranges of :
- Ecosystems and habitats
- Species and abundance
- Genetic variation within species

Question 2

What is ecosystem or habitat diversity?

Answer 2

• Range of different ecosystems or habitats in a particular region
• If there are lots of habitats, there is a high biodiversity
• Lots of niches

Question 3

What is species richness?

Answer 3

• Number of species within an ecosystem

Question 4

What is species diversity?

Answer 4

Combination of
- Species evenness
- Species richness
- The greater number of species in an ecosystem, and the more EVENLY DISTRIBUTED the numbers of individuals from each species, the greater the species diversity
- Higher species diversity, more stable the ecosystem (more resistant to environmental changes)

Question 5

What is genetic diversity?

Answer 5

• Diversity of alleles and genes in the genome of a species
• Individuals of the same species may have the same genes, but not necessarily same alleles
• There can be genetic differences (diversity) between populations of the same species, because 2 populations may occupy different ranges in their habitats so subject to slightly different selection pressures
• Helps organisms to resist to changes in the environment and ADAPT
• New factors such as new predators or pathogens or competition could be changes in the environment, even abiotic factors
• In small populations, genetic diversity limited, inbreeding can occur in higher proportions of individuals, so larger proportion of organisms are homozygous, so low genetic diversity, so genetic diseases caused by recessive alleles are more common in these populations