4.2.4 calculating biodiversity

Question 1

allele or gene variant

Answer 1

version of a gene

Question 2

locus

Answer 2

position of that gene on a chromosome

Question 3

polymorphic gene locus

Answer 3

locus that has 2+ alleles

Question 4

simpsons index of biodiversity

Answer 4

measure of biodiversity in a habitat

Question 5

species evenness

Answer 5

measure of how evenly represented species are

Question 6

species richness

Answer 6

measure of how many different species are present

Question 7

what do we have to consider when measuring biodiversity

Answer 7

species richness & species evenness

Question 8

how can species richness be measured

Answer 8

by counting all species present in habitat

Question 9

how can species evenness be measured

Answer 9

must carry out quantitative survey

Question 10

how can we survey the frequency of plants

Answer 10

1. use sampling techniques eg. quadrat, transect
2. record percentage cover of each plant species
   –> with large plants, its better to count number of individuals per unit area

Question 11

what does it mean to measure density of animals in a habitat

Answer 11

calculating how many animals of each species there are per unit area of a habitat

Question 12

how do we measure the density of animals in a habitat of:
- larger animals
- smaller animals

Answer 12

• counted by observation
• counted using sampling techniques

Question 13

how can the population size be calculated of:
- smaller animals
- tiny animals living in soil

Answer 13

• mark-and-recapture technique
• take sample of soil & sift through to find individuals & count

Question 14

formula of simpsons index of biodiversity & what does each symbol stand for

Answer 14

pg. 260 of textbook or class booklet

Question 15

what does a high value for the simpsons index indicate

Answer 15

highly diverse habitat
- many different species & organisms live here
- change to environment may impact 1 species & if only a small part of habitat, the total number of individuals affected is small proportion
- habitat stable & able to withstand change

Question 16

what does a low value for the simpsons index indicate

Answer 16

habitat dominated by few species
- small change to environment which affects 1 species could damage/destroy whole habitat
- such small change could be disease/predator

Question 17

what’s the genetic diversity like of isolated populations & how can it be measured

Answer 17

• genetic diversity is limited
• assessing it can help assess value of population as resource for conservation
• simple assessment made by looking at observable features

Question 18

when is genetic diversity found

Answer 18

more than one allele for particular locus = variations between individuals which may be easily observable
–> means more genetic differences between gametes produced by members of population

Question 19

how can genetic diversity be estimated

Answer 19

• by calculating number of loci in one individual that are heterozygous BUT doesn’t give good measure of value of population as genetic resource
• another measurement involves calculating percentage of loci in population which have more than 1 allele

Question 20

what increases genetic diversity

Answer 20

having more than 2 alleles at a locus (polymorphic gene loci)