4.2.1 Biodiversity

Question 1

Species diversity

Answer 1

• Number of different species and individuals within each species in a community

Question 2

Genetic diversity

Answer 2

• Variety of genes amongst all the individuals in a population of one species

Question 3

• Habitat diversity

Answer 3

Range of different habitats

Question 4

Species richness

Answer 4

-Number of different species in a particular area at the particular time

Question 5

• Species evenness

Answer 5

• Relative abundance of each different species within the community

Question 6

Genetic diversity

Answer 6

• Calculated by examining polymorphic genes within isolated populations
• Polymorphic gene - has more than one allele
• Proportion of polymorphic gene loci = number of polymorphic gene loci/total number of loci
• Higher proportion = larger genetic diversity

Question 7

Representative sampling

Answer 7

• Take a large sample: calculate a mean + stats test to see if any differences or correlations seen are significant
• Randomly sample: avoid bias

Question 8

Random sampling

Answer 8

• Lay out two tape measures at right angles to each other - create a gridded area
• Use random number generator to generate 2 numbers to serve as coordinates

Question 9

Opportunistic sampling

Answer 9

• Unlikely to result in a sample that accurately represents the population
• Involves sampling organisms which are conveniently available - involves bias

Question 10

Stratified sampling

Answer 10

• Some populations/habitats can be separated into groups/strata to sample from
• Sampling pond - split into 3 groups: surface, shallow, deep-water + take random samples

Question 11

Systematic

Answer 11

• Identifying different areas within a habitat to sample
• Used when there is a change in the distribution of species within the habitat
• Want to investigate the impact of the change on biodiversity
• Often involves a belt transect

Question 12

Using a Quadrat

Answer 12

Density: count the individuals present
Frequency: gridded frame quadrat, count how many squares of the total the species are present in - turn into a % out of 100
Percentage cover: estimate % of the entire quadrat covered with the species being investigated - quick but subjective = lower accuracy

Question 13

Factors affecting biodiversity

Answer 13

• Human population: increasing at an exponential rate
  Increased need space for housing, farming + industry
• Agriculture: Increased to feed everyone
  Clearing land results in destruction of habitats, chemical pesticides/fertilisers added - monocultures grown
  Reduces number of habitats + range of food sources
• Climate change: Increase in global temp - melting polar ice caps - destroying habitats
  Sea levels rising - reducing biodiversity due to flooding
• Higher temp, lower rainfall - some plants + animals unable to survive
• Xerophytes becoming dominant species + outcompeting others

Question 14

Reasons to maintain biodiversity

Answer 14

• Ecological: All organisms interdependent on each other - loss of one species impacts all others
  Essential to put in conservation measures to protect habitats while still producing food for humans
• Economic: Deforestation -soil erosion + monocultures - soil becomes deficient in specific minerals that the crop absorbs a lot of.
  Results in soil depletion + negative on ability to grow crops.
  Tourism relies on people visiting areas of natural beauty + animals - reduce tourism + impact economy.
  Many medicines based on chemicals naturally occurring in plants
• Aesthetic: Being in nature enriches people’s lives
  Creative inspiration for art, music, writers
  Improves people’s mental health

Question 15

In situ conservation

Answer 15

• Conservation happens with the habitat, genetic biodiversity maintained - not bred captively
• All organisms interdependent - preventing extinction of one species impacts all the other species dependent on it
• Marine conservation zones - areas designated for wildlife to recover + repopulate
• Wildlife reserves - same concept but on land

Question 16

Ex situ conservation

Answer 16

• Removing organisms from natural habitat to protect them
• Botanical gardens, seed banks + captive breeding
• Seed banks: store of genetic material, seeds of variety of plants stored in water + temp controlled environments to keep the viable for longer
  Stored as a backup for potential plant species that may go extinct
  Captive breeding: reproducing animals in zoos + aquariums - increase number of endangered species + reintroduced into the wild

Question 17

Conservation on International Trade in Endangered Species (CITES)

Answer 17

• Regulates international trade of endangered animals, plants + products
• Drives price of banned substance up through illegal trading

Question 18

Rio Convention on Biological Diversity (CBD)

Answer 18

• Countries must come up with strategies for sustainable development
• Stabilise greenhouse gas emissions + conc within atmosphere
• Prevent destruction of fertile land into desert + reduce effects of drought
• Share access to scientific knowledge + tech

Question 19

Countryside Stewardship Scheme (CSS)

Answer 19

• Setup to protect + enhance natural environment