3.4.6 Biodiversity within a community 3.4.7 Investigating diversity Flashcards
What are 4 ways genetic diversity between species can be compared?
- 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
Explain how genetic diversity is compared with a DNA/mRNA base sequence
- 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
How is genetic diversity compared by using amino acid sequence of polypeptides?
- 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
How can genetic diversity be investigated by comparing frequency of measurable and observable characteristics?
- genes determine observable characteristics (phenotype)
- so variety depends on number and variety of alleles
What is species richness?
- number of different species in a community
What is species diversity?
- number of different species and number of individuals of each species in a community
What is biodiversity
- species: number of different species
- genetic: number of different alleles of genes
- ecosystem: number of different habitats
What is the index of diversity formula? What do N and n represent?
d = N(N -1)
En(n-1)
- N = total number of organisms of all species
- n = total number of organisms of each species
What conservation techniques can make farming more sustainable?
- 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
What impacts of agriculture result in lower species diversity?
- deforestation for land
- monocultures
- removal of hedgerows
- pesticides and herbicides
- use of inorganic fertilisers
- no crop rotation
- inorganic fertilisers - leach into rivers (eutrophication)
What are impacts of monoculture farming?
- 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
How can plants increase diversity index?
- more variety of different plant species
- greater variety of different food sources
- more different habitats
What is the difference between interspecific and intraspecific variation?
- Interspecific - one species varies from another species
- Intraspecific - where members of the same species differ from each other
Describe the process of random sampling
- 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
How can you reduce chance by using a large sample size?
- 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
What are 3 ways to get a representative sample?
- random sampling (reduces bias)
- large sample size (reduce chance)
- statistical test (eg T-test, Chi-squared, Spearman’s rank) (reduces chance)
Give 3 advantages/uses of random sampling
- avoids bias
- ensures each side of the meadow is sampled
- good for species with uniform distribution (equally spread between each region in area)
Index of diversity definition
RELATIONSHIP between number of species and number of individuals in each species
Why has knowledge of prokaryotic biodiversity increased in recent years
- DNA sequencing can now be used
- can analyse more prokaryotic species in the community
- rather than just recording measurable characteristics
Why is index of diversity useful?
- may be many of some species and few of other species
How can you measure the flow of a river
- movement of floating object over known distance in given time
- data logging device (flow meter)
Why might there be fewer individuals of a species at a particular area?
- less food, so more starve
- less oxygen, so less aerobic respiration
- more preditors, so more eaten
- more competition, so more starve
