3.4.6 Biodiversity within a community 3.4.7 Investigating diversity

Question 1

What are 4 ways genetic diversity between species can be compared?

Answer 1

• by comparing the frequency of measurable/observable characteristics
• by comparing the DNA base sequence
• by comparing the mRNA base sequence
• by comparing the amino acid sequence of polypeptides

Question 2

Explain how genetic diversity is compared with a DNA/mRNA base sequence

Answer 2

• use DNA sequencing
• DNA base sequence of closely related species is more similar than less closely related species
• differences in DNA base sequence arise due to mutation

Question 3

How is genetic diversity compared by using amino acid sequence of polypeptides?

Answer 3

• amino acid sequence of closely related species is more similar than less closely related species
• however DNA code is degenerate so differences in DNA base sequence may not be seen in amino acid sequence
• 2 sequences compared by counting the number of similarities or differences in each sequence

Question 4

How can genetic diversity be investigated by comparing frequency of measurable and observable characteristics?

Answer 4

• genes determine observable characteristics (phenotype)
• so variety depends on number and variety of alleles

Question 5

What is species richness?

Answer 5

• number of different species in a community

Question 6

What is species diversity?

Answer 6

• number of different species and number of individuals of each species in a community

Question 7

What is biodiversity

Answer 7

• species: number of different species
• genetic: number of different alleles of genes
• ecosystem: number of different habitats

Question 8

What is the index of diversity formula? What do N and n represent?

Answer 8

d = N(N -1)
En(n-1)

• N = total number of organisms of all species
• n = total number of organisms of each species

Question 9

What conservation techniques can make farming more sustainable?

Answer 9

• plant hedgerows rater than fences - provide habitats or corridors between habitats
• increase genetic diversity with native species
• use biological control or genetically modified organisms not pesticides
• organic fertilisers not inorganic
• crop rotation not fertilisers
• maintain ponds and marshes

Question 10

What impacts of agriculture result in lower species diversity?

Answer 10

• deforestation for land
• monocultures
• removal of hedgerows
• pesticides and herbicides
• use of inorganic fertilisers
• no crop rotation
• inorganic fertilisers - leach into rivers (eutrophication)

Question 11

What are impacts of monoculture farming?

Answer 11

• species selectively bred so low genetic diversity
• reduces land space for wild animals so reduces species diversity
• farmland created, less habitats available, less species supported, species diversity decreases
• pesticides used freely- enter food chain and kill species, lowering diversity

Question 12

How can plants increase diversity index?

Answer 12

• more variety of different plant species
• greater variety of different food sources
• more different habitats

Question 13

What is the difference between interspecific and intraspecific variation?

Answer 13

• Interspecific - one species varies from another species
• Intraspecific - where members of the same species differ from each other

Question 14

Describe the process of random sampling

Answer 14

• divide area into a grid
• use a random number generator to produce random coordinates
• place quadrats at those coordinates and sample
• ( record frequency or % cover)
• repeat many times and calculate a mean to multiply by total area

Question 15

How can you reduce chance by using a large sample size?

Answer 15

• do many repeats (10 or more)
• to obtain a more reliable mean
• to reduce the effect of extreme values/ identify anomalies
• ensure sample was representative

Question 16

What are 3 ways to get a representative sample?

Answer 16

• random sampling (reduces bias)
• large sample size (reduce chance)
• statistical test (eg T-test, Chi-squared, Spearman’s rank) (reduces chance)

Question 17

Give 3 advantages/uses of random sampling

Answer 17

• avoids bias
• ensures each side of the meadow is sampled
• good for species with uniform distribution (equally spread between each region in area)