Higher Biology 3.7 & 3.8 Components & Threats to Biodiversity

Match the following components of biodiversity to their definitions

• Relative abundance

• number and frequency of all the alleles within a population.

• Species richness

• proportion of each species in the ecosystem

• Ecosystem Diversity

• number of distinct ecosystems within a defined area.

• Genetic Diversity

• number of different species within an area

Within a species, if one population dies out (for example within a species of fish, if one whole population in an area dies out) the species will experience ​ (a)   in genetic diversity

• loss
• gain

Answer explanation

when a population dies out, those alleles are now wiped out from the species.

Genetic diversity is the frequency and number of different alleles in an area, so if we lose a full population this will GO DOWN

Look at the 2 areas. Which area is more diverse?

• 1

• 2

Answer explanation

Area 1 is less diverse/area 2 more diverse as we can see in area 1 it has a dominant species, higher proportion of seals

Which statement is true of the 2 areas?

• Both areas have the same species richness

• The areas have a different species richness

Answer explanation

Area 1 has one more species, the penguins, therefore their species richness is not the same in the different areas.

Remember, species richness is the number of different species in an area.

When a population has been overexploited to the point the remaining population is very small with reduced genetic diversity this is known the

Give an example a negative impact the bottleneck effect can have on a population

Answer explanation

- Inbreeding occurs, leading to lower reproductive rates (due to inbreeding depression)

- They are less able to evolve and adapt to environmental changes (because of the loss of genetic diversity)

This picture shows an example of a threat to biodiversity. This is known as

Once habitat fragmentation occurs, over time the edges of the fragments become degraded and fragments become ​ (a)   this results in an ​ (b)   in competition between species and decreases biodiversity. More isolated, smaller fragments have a ​ (c)   species diversity.

• smaller
• larger 
• increase
• decrease
• lower
• higher

What is the purpose of habitat corridors?

Answer explanation

habitat corridors LINK THE ISOLATED FRAGMENTS

How could a habitat corridor increase biodiversity after a local extinction?

Answer explanation

the habitat corridor allows the animals t move between the fragments, then increasing their access to food and a choice of mate.