Population & Sustainability

Question 1

r- and k-strategists

Answer 1

represent 2 ends of a continuum of strategies adopted by living things

Question 2

k-strategists

Answer 2

species who population is determined by carrying capacity

Question 3

r-strategists

Answer 3

population size increases so quickly it can exceed capacity before limiting factors start to have an effect

Question 4

most important influence on population growth

Answer 4

physical rate (r) at which individuals can reproduce- bacteria and pioneer species

Question 5

which colonise during succession first

Answer 5

pioneer r-strategist during fast population growth before k-strategists disperse to other habitats as limiting factors take affect

Question 6

carrying capacity

Answer 6

the maximum population size that can be maintained over a period in a particular habitat

Question 7

limiting factor

Answer 7

factor whose magnitude slows down the rate of a natural process

Question 8

competition

Answer 8

when resources not present in adequate amounts to satisfy needs of all individuals who depend on them

Question 9

intraspecific competition

Answer 9

individuals of same species compete for food so those best adapted obtain, survive, reproduce so slows pop. growth, entering stationary phase

Question 10

interspecific competition

Answer 10

affects both pop. size of different species and distribution within ecosystem

Question 11

as intensity of competition increases…

Answer 11

rate of repro. decreases but DR increase as fewer organisms have resources

Question 12

why doesn’t the competitive exclusion principle always apply in natural ecosystems

Answer 12

environmental conditions always changing so will be a variety of limiting factors with differing strength —> pop. growth vary too much to conclude one species grows in one place

Question 13

preservation

Answer 13

keeping species/habitats as they are now by keeping things natural and eliminating any human effects on ecosystems that exist today

Question 14

conservation

Answer 14

more active management process involving human intervention, maintaining/improving biodiversity (also genetic diversity) and range of habitats/ecosystems

Question 15

threats to biodiversity

Answer 15

over-exploitation for food/sport/commerce
intensive agri/increased pollution/widespread building –> habitat destruction
species introduced–> outcompete native species

Question 16

effects on community when deciding conservation strategies

Answer 16

social/economic costs to local community, effective education/liason with community

Question 17

examples of conservation strategies

Answer 17

extra food to raise carrying capacity, control predators/poachers, vaccinate, restrict succession, dispersal corridors

Question 18

ethical reasons for conservation

Answer 18

species has value, human responsibility, arguments in favour of human activities are objective/driven by economics

Question 19

economic/social reasons for conservation

Answer 19

genetic diversity need in future to breed resistance etc, food source, predators act as biological control agents, ecotourism

Question 20

small scale methods of managing timber production

Answer 20

coppicing, pollarding, rotational coppicing, standards

Question 21

large scale methods of managing timber production

Answer 21

felling, selective cutting, sustainable management (planting)

Question 22

issues associated with felling large areas of trees

Answer 22

destroy habitats, reduce soil mineral levels, soil susceptible to erosion, not remove water/stop washing into waterways, not maintain levels through carbon/nitrogen cycles