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)

Question 18

Index of diversity definition

Answer 18

RELATIONSHIP between number of species and number of individuals in each species

Question 19

Why has knowledge of prokaryotic biodiversity increased in recent years

Answer 19

• DNA sequencing can now be used
• can analyse more prokaryotic species in the community
• rather than just recording measurable characteristics

Question 20

Why is index of diversity useful?

Answer 20

• may be many of some species and few of other species

Question 21

How can you measure the flow of a river

Answer 21

• movement of floating object over known distance in given time
• data logging device (flow meter)

Question 22

Why might there be fewer individuals of a species at a particular area?

Answer 22

• less food, so more starve
• less oxygen, so less aerobic respiration
• more preditors, so more eaten
• more competition, so more starve