ATAR Unit 3 (1)

Question 1

biodiversity

Answer 1

variety of all living things; derived from ‘bio’ - meaning life & ‘diversity’ - meaning variability

Question 2

three levels of biodiversity

Answer 2

genetic diversity - variety of genes within a species

species diversity - variety of species within a habitat

ecosystem diversity - variety of ecosystems in a given place

Question 3

why is biodiversity important ?

Answer 3

increases ecosystem stability / resilience

provides commodities for humans [e.g. medicine]

Question 4

random sampling

Answer 4

sampling randomly to capture an unbiased representation of an ecosystem

Question 5

systematic sampling

Answer 5

sampling orderly through transects [lines / belts across the site]

Question 6

stratified sampling

Answer 6

sampling separately by identifying areas within the site & dividing them into zones [strata / layers]

Question 7

quadrat sampling

Answer 7

sampling using quadrats

Question 8

line transect

Answer 8

sampling using straight lines w. set intervals

Question 9

belt transect

Answer 9

sampling using straight lines w. quadrats

Question 10

species richness

Answer 10

tally of number of different species within a particular area

number of species divided by square root of total number of individuals

Question 11

percentage cover

Answer 11

measurement of the proportion of an area covered by an organism

ground cover [area]
basal cover [stem area]
canopy cover [total aerial cover]

organism’s cover divided by total area
multiplied by a hundred for percentage

Question 12

percentage frequency

Answer 12

measure of how often a species of plant appears within the quadrats sampled

number of quadrats with the species of plant divided by number of total quadrats multiplied by a hundred for percentage

Question 13

species abundance

Answer 13

number of individuals of a particular species in an area

number of individuals of a species

Question 14

species evenness / relative abundance

Answer 14

measure of number of individuals of a particular species in relation to total number of individuals of all species in an area

species abundance divided by number of total individuals from all species multiplied by a hundred for percentage

Question 15

simpson’s diversity index

Answer 15

measurement of both species richness and species evenness

1 − {[∑n(n−1)] / [N(N−1)]}

n : number of individuals of a specie
N : total number of individuals of all species

Question 16

distribution

Answer 16

where an organism is found

Question 17

abundance

Answer 17

how many of an organism is found

Question 18

biotic factors

Answer 18

predator & prey

competition

symbiosis

Question 19

abiotic factors

Answer 19

temperature

light intensity

water availability

Question 20

limit on distribution & abundance of species [biotic]

Answer 20

if distribution / abundance of a species changes, distribution / abundance of other species it interacts w. changes [e.g. prey availability determines predator distribution & abundance]

Question 21

limit on distribution & abundance of species [abiotic]

Answer 21

distribution is confined to a tolerance range

abundance is greatest in an optimum range & decreases outside this range

Question 22

interspecies competition

Answer 22

competition for resources [food, mates, etc…] between members of different species [e.g. predators of different species hunting for the same prey]

Question 23

intraspecies competition

Answer 23

competition for resources [food, shelter, etc…] between members of the same species [e.g. males of the same species competing for the same mate]

Question 24

predator-prey

Answer 24

one species kills & eats another species [e.g. eagles hunting rabbits]

Question 25

parasitism

Answer 25

one species [parasite] lives & feeds from another species [host] [e.g. leeches in humans]

Question 26

mutualism

Answer 26

both species benefit [e.g. algae providing food for fungi & fungi providing protection for algae in lichen]

Question 27

commensalism

Answer 27

one species benefits & the other species is unaffected [e.g. clownfish receiving food & protection from anemone]