Chapter 11: Biodiversity

Question 1

Define species.

Answer 1

• Group of organisms that are capable of breeding to produce fertile offspring.

Question 2

Define population.

Answer 2

• The total number of individuals of a single species in a defined area.

Question 3

Define community.

Answer 3

• All the organisms living in a particular ecosystem.

Question 4

Define ecosystem.

Answer 4

• A section of the living world characterised by a particular set of environmental conditions with an interacting community of organisms.

Question 5

Define habitat.

Answer 5

• Place where an organism lives.

Question 6

Define biodiversity.

Answer 6

• Variety of species in an area.
• Variety of habitats/ecosystems.
• Variety of alleles/genes.

Question 7

Define species richness.

Answer 7

• The no. of different species living in a defined area.

Question 8

Define species evenness.

Answer 8

• A comparison of the no. of individuals of each species living in a community.

Question 9

What is sampling bias?

Answer 9

• The deliberate or accidental selection of a particular area to sample within a habitat due to subjective values (e.g. interest).

Question 10

What is chance in reference to sampling?

Answer 10

• Sample isn’t accurate representative of entire population.

- Increase sample size to counter this.

Question 11

Methods of sampling animals.

Answer 11

• Pooter.
• White sheet under tree + shake tree.
• Pitfall trap.
• Tullgren funnel.
• Capture/re-capture.
• Light trap.

Question 12

What does a high Simpson’s Index of Diversity indicate?

Answer 12

• Large no. of successful species.
• Low stress environment with many ecological niches.
• Many species live in one habitat, with very few specific adaptations to the environment.
• Environmental changes has little effect on habitat.
• Complex food webs.
• Stable habitat.

Question 13

What does a low Simpson’s Index of Diversity indicate?

Answer 13

• Few successful species.
• High stress environment with few ecological niches.
• Few species live in one habitat, with very specific adaptations to the environment.
• Environmental changes has large effect on habitat.
• Simple food webs.
• Unstable habitat.
• Dominated by one species.

Question 14

What factors increase GB?

Answer 14

• Mutations.
• Gene flow –> interbreeding between members of two different pops.
• High proportion of polymorphic gene loci.

Question 15

What factors decrease GB?

Answer 15

• Natural selection.
• Founder effect –> small member of pop. migrates to new environment with new selection pressures –> adapts to new selection pressure but small pop. means small gene pool.
• Genetic bottlenecks –> few members of a pop. survive natural disaster –> reduced gene pool.
• Selective breeding.
• Captive breeding.
• Genetic drift.
• Low proportion of polymorphic gene loci.

Question 16

How does deforestation affect biodiversity.

Answer 16

• Directly reduces no. of trees present in an area.
• If only a specific tree species is cut down –> greatly reduces species diversity for that type of tree.
• Reduces no. of animal species in an area –> removes their food source, habitat + home –> reduces food source of another species.
• Animals forced to migrate to other areas to ensure survival –> increases biodiversity of neighbouring areas.

Question 17

Examples of in situ conservation.

Answer 17

• Controlled grazing.
• Feeding –> to reproductive age.
• Restricting human access.
• Controlling poaching.
• Marine conservation zones.

Question 18

When is ex situ conservation used?

Answer 18

• When habitat/ecosystem is lost/damaged due to natural disaster or climate change.
• When sexual reproduction in pop. is low.
• To preserve gene pool/genetic diversity.
• Protection from predators, disease and pathogens.
• When pop. in habitat is very low.

Question 19

Advantages of seed banks (ex situ).

Answer 19

• Seeds extracted with minimal damage to environment.
• Can store a greater genetic diversity.
• Take up little space to store.
• Cheaper man power costs.
• Cheaper + easier to transport.
• Remain viable for long periods of time.
• Less susceptible to disease/environmental change/pests.
• Prevents fertilisation by undesired pollen.

Question 20

Purpose of ‘Convention on International Trade in Endangered Species (CITES)’?

Answer 20

• Regulate trade of endangered species.
• Ensures trade does not endanger wild pops.
• Prevent trade of wild plant pops.
• Allow trade of artificially propagated plants.
• Allows trade of less endangered wild species/organisms.

Question 21

Purpose of Rio Convention?

Answer 21

• Sustainable use of organisms.
• Sharing of genetic resources.
• Sharing of scientific knowledge + technology.
• Promote ex situ conservation.
• Raise biodiversity profile with government + general public.
• Programmes of international cooperation to combat biodiversity issues.