3.4.6 biodiversity

Question 1

what is genetic diversity?

Answer 1

the number of different alleles of genes in a population.

Question 2

what is species diversity?

Answer 2

the number of different species in a community (species richness) and the number of individuals of each species (species evenness).

Question 3

what is ecosystem diversity?

Answer 3

the range of habitats.

Question 4

what is an ecosystem?

Answer 4

the interaction of different specie san they interact with the environment.

Question 5

difference between species richness and evenness:

Answer 5

species richness = number of different species within a community.
- the more species present the richer the habitat.

species evenness = number of individuals of each species.
- relative abundance of each species and population size.
- habitat with even numbers of species in more diversity than one with a dominant species.

Question 6

what is Simpson’s index of biodiversity?

Answer 6

• diversity index is a better way of describing biodiversity.
• takes into account species richness and evenness.
• simpson’s index measures the diversity of a habitat.

DI = N(N-1)/ sum of n(n-1)

N= total number of individuals collected
n = number of individuals of a species

Question 7

why should biodiversity be maintained?

Answer 7

• MORAL AND ETHICAL, humans have responsibility to reduce their impact on the planet and other species.
• ECOLOGICAL, biodiversity increases stability of ecosystems.
• ENVIRONMENTAL, organisms provide essential environmental resources.
• ECONOMIC, a range of organisms contribute to medicine, science etc.
• AESTHETIC, humans take pressure from visual effects of biodiversity.
• AGRICULTURAL, genetically diverse wild species can rescue crops.

Question 8

what are the direct impacts of farming on biodiversity?

Answer 8

• removal of hedgerows = removal of safety and habitats.
• monocultures = less insects, less variety of food and food sources.
• filling in ponds/draining marshlands.
• overgrazing of land = decrease variety of nutrients in soil.

Question 9

what are the indirect impacts of farming on biodiversity?

Answer 9

• pesticides/fertilisers = eutrophication, pesticides are not targeted and bio-accumliation.
• escape of silage stores and slurring into water sources = pollution causing decrease in oxygen as there is an increase in bacteria.
• absence of crop rotation and lack of intercropping.

Question 10

what affect does agriculture have on biodiversity?

Answer 10

• number of species and genetic variation is decreasing = less variety of food and habitats for animals so animal diversity reduced.
• due to:
  > herbicides killing weeds.
  > rapid growth of crops and clearing areas for crop growth (high competition and few species).
  > monoculture.
  > reduced ecosystem diversity = removal of hedgerows and drainage of ponds.

Question 11

what are the current conservation measures to increase ecosystem diversity?

Answer 11

• replanting/maintaining hedgerows.
• digging ponds.
• producing hay from natural meadows rather than grass.

Question 12

what are the current conservation measures to increase opportunities for species diversity?

Answer 12

• biological control rather than pesticides = use of one species to kill another.
• crop rotations.
• natural fertilisers = reduced risk of eutrophication and slower release to reduce competition.