1. Biodiversity

What does biodiversity mean?

Biodiversity is the number of species in a given area and the variety of different alleles in the gene pool of a species.

Suggest the two types of variety in an area?

1. the number of different species

2. the genetic diversity

Suggest what is meant by an endemic species?

An endemic species is a species which is found in only one specific geographical location.

What could be causing a decrease in

biodiversity?

• Habitat destruction

• Overexploitation

• Hunting

• Agriculture

• Climate change

Why should we care about biodiversity?

• Endemic species are becoming extinct

• There are fewer different species

• Useful species may be lost before they are discovered

EQ: Discuss why it is important to conserve the biodiversity of the world's ecosystems (3)

1. Idea that loss of biodiversity means fewer species (1)

2. Idea that the loss of endemic species leads to extinction (1)

3. Idea that species lost (1)

How can biodiversity be measure within a habitat?

Species Richness: The number of (different) species in a habitat.

How can biodiversity be measure within a species?

Genetic Diversity by calculating the heterozygosity index (H):

number of heterozygotes/ number of individuals in the population

How can biodiversity be measure between habitats?

Simpson's Diversity Index

Suggest what is meant by the term species richness:

The number of species in a particular location

What is it used for?

To measure biodiversity within a habitat

Suggest the disadvantages using species richness as a measure of biodiversity?

• No indication of the abundance of each species

• It doesn't calculate the genetic diversity

What is species evenness?

Species evenness refers to how close in abundance each species in an environment is

How does species evenness affect biodiversity?

The higher the species evenness the greater the biodiversity

What is genetic diversity?

The total number of different alleles in a gene pool

Where does genetic diversity come from?

1. Mutations - random change in the DNA base sequence

2. Production of gametes -

   Haploid cells produced

   Crossing over can occur

   Independent assortment of homologous chromosomes

3. Sexual Reproduction -

Sexual reproduction increases genetic diversity

What processes reduce genetic diversity?

1. Population decline

Less individuals, means frequency of different alleles reduces. This reduces genetic diversity.

2. Natural Selection

Only advantageous alleles are selected for and passed onto offspring. This means natural selection reduces genetic diversity

Why is genetic diversity important?

1. It reduces the likelihood that a species will become extinct

2. It reduces inbreeding depression

→ The reduction in survival and health of animals due to recessive mutations

What problems could be caused as a result of inbreeding depression?

1. Elevated incidence of recessive genetic diseases

2. Reduced fertility both in litter size and in sperm viability

3. Increased congenital defects such as cryptorchidism, heart defects, cleft palates.

4. Fluctuating assymetry (such as crooked faces, or uneven eye placement and size).

5. Lower birthweight/Higher neonatal mortality 6. Slower growth rate/Smaller adult size, and 7. Loss of immune system function.

Explain the importance of having high genetic variation within a population of organisms:

• Allows species to adapt to changes in the environment (such as the introduction of a new disease)

• Reduces the risk of inbreeding depression (reduction in survival and health of animals due to recessive mutations)

• Decreases the risk of extinction

• inbreeding depression occurs when closely related animal breed together

What is the formula for heterozygosity index (H)?

number of heterozygotes /

number of individuals in the population

What is a heterozygote?

Aa