6.3.2 populations and sustainibility

Question 1

what is carrying capacity
6.3.2(a)

Answer 1

maximum population size an environment can support .

Question 2

what is carrying capacity determined by
6.3.2(a)

Answer 2

limiting factors

Question 3

describe a typical population growth curve at A
6.3.2(a)

Answer 3

a-lag phase-birth rate is higher than death rate so population increases in size

Question 4

describe a typical population growth curve at B
6.3.2(a)

Answer 4

b-log phase-birth rate is higher than death rate. The population size increases exponetially

Question 5

describe a typical population growth curve at C
6.3.2(a)

Answer 5

C-stationary phase-population size levels out at/near to cqrrying capacity. birth and death rate are equal. Population will stay stable or fluctuate slightly up and down

Question 6

what are limiting factors
6.3.2(a)

Answer 6

prevent further growth of a populations and in some cases cause it to decline

Question 7

what are density dependant factors
6.3.2(a)

Answer 7

limiting factors that have a stronger effect on larger populations

Question 8

what are density independant factors
6.3.2(a)

Answer 8

limiting factors that have an effect on the whole population regardless of its size

Question 9

what are examples of density dependant factors
6.3.2(a)

Answer 9

-availibility of resources- eg-food, water, light, oxygen-there will be more competition when population size is high
-parasitism and disease-more easilt transmitted in populations that are competing for space
-predation-will increase as prey population size increases too

Question 10

what are examples of density independant factors
6.3.2(a)

Answer 10

-earthquakes
-fires
-volcanic eruptions
-storms

Question 11

how can migration cause a sudden change in population size
6.3.2(a)

Answer 11

migration can also cause sudden changes in population size if individuals arrive (immigration) or leave (emigration). Ultimately the population will return to carrying capacity

Question 12

what is interspecific competition
6.3.2(b)

Answer 12

competition between individuals of different species

Question 13

what does interspecific competition affect
6.3.2(b)

Answer 13

population and distribution of species

Question 14

what happens in interspecific competition when two organisms are competing for the same resources
6.3.2(b)

Answer 14

each organism will consume less food so will have less energy for growth and reproduction. This results in both organisms having smaller populations than if only one was present

Question 15

what happens in interspecific competition when two organisms are competing for the same resource but one is better adapted
6.3.2(b)

Answer 15

the less well adapted species is likely to be outcompeted. It will decline in numbers until it can no longer exist in the habitat alongside the better adapted species

Question 16

what is the competition exclusion principle
6.3.2(b)

Answer 16

when two species are competing for limited resources, the one that uses the resources more efficiantly will outcompete the other

Question 17

what is intraspecific competition
6.3.2.(b)

Answer 17

when members of the same species compete for the same resource

Question 18

why does the number of organisms fluctuate in intraspecific competition
6.3.2(b)

Answer 18

the availibilty of resources determines the population size. The more resources available the larger the population that can be supported

Question 19

describe stages 1-3 in the fluctuations of organism size
6.3.2(b)

Answer 19

stage 1-when resources are plentiful in a habitat the organism has enough resources to survive and reproduce so population size will increase
stage 2-as a result of the increased population more individuals share resources eg-food/water. Resources are now limited so the population will decrease in size.
stage 3-smaller population leads to less competition. This means more organisms survive and reproduce increasing population size.

Question 20

how can predation affect a prey animals population size
6.3.2(b)

Answer 20

1. predation population increases more prey are eaten
2. prey population decreases so less food for predators
   3.with less food fewer predators can survive so there population reduces
   4.with fewer predators fewer preys are eaten so prey population size increases
3. with more prey the predator population size increases

Question 21

what is a predator
6.3.2(b)

Answer 21

a predator is an animal that hunts other prey animals for food.

Question 22

why dont the curves line up in the predator-prey graph
6.3.2(b)

Answer 22

due to the time lags taken for predators and prey to reproduce

Question 23

what is preservation
6.3.2(c)

Answer 23

keeping species and habitats as they are now or allowing them to naturally re wild without any human intervention

Question 24

what does preservation involve
6.3.2(c)

Answer 24

restriction or complete ban on human access and is used for habitats that are sensitive to human disturbance eg-fragile cave or costal ecosystems

Question 25

what is preservation suitable for 6.3.2(c)

Answer 25

habitats that would be stable for a long time without human interference

Question 26

what is conservation 6.3.2(c)

Answer 26

involves human intervention -active management of the ecosystem through restoring biodiversity -involves sustainable use of the resources

Question 27

what is the reclamation approach used in conservation 6.3.2(c)

Answer 27

restoring ecosystems that have been damaged or destroyed

Question 28

how does conservation manage ecosystems 6.3.2(c)

Answer 28

involves management of ecosytems so resources can be used without running out

Question 29

what are some economic reasons to maintain biodiversity 6.3.2(c)

Answer 29

-medicines can be patened and sold -ecotourism can bring money in

Question 30

what are some social reasons to maintain biodiversity 6.3.2(c)

Answer 30

-people enjoy the natural beauty of wild ecosystems and landscapes -people enjoy using natural ecosystems for lesiure activities/ exersize/ relaxation -access to green spaces has been proven to be beneficial to mental and physical health

Question 31

what are some ethical reason to maintain biodiversity 6.3.2(c)

Answer 31

humans do not have a right to cause extinction We also have a moral responsibility to conserve ecosystems for future generations

Question 32

how can you manage small scale timber production 6.3.2(d)

Answer 32

coppicing

Question 33

what is coppicing 6.3.2(d)

Answer 33

cut the stem of a tree. This allows new shoots to grow from the cut surface. These shoots can be harvested

Question 34

what are the benefits of coppicing 6.3.2(d)

Answer 34

1. increases life span of treees 2.different areas of woodland have different light levels which increases species biodiversity 3.reduces soil erosion so soil quality is maintained

Question 35

how can you manage large scale timber production 6.3.2(d)

Answer 35

clear felling

Question 36

how do you reduce soil erosion for clear felling 6.3.2(d)

Answer 36

1. limit size of felled area 2.replant felled trees 3.allow trees to fully regrow before harvesting

Question 37

how do we ensure each tree supplies more wood 6.3.2(d)

Answer 37

1. control pests and pathogens 2. plant plants where we know they will grow well 3. position trees an optimal distance apart to reduce competition

Question 38

what are some ways we are trying to sustainably fish 6.3.2(d)

Answer 38

-fishing quotas-international agreements about the number of fish of each species that can be caught -use large size nets to allow juvenile fish to escape and reach reproductive age -allow fishing at certain times of the year to protect breeding season of fish -fish farming

Question 39

how can you manage the conflict between conservation and human need in the massai mara 6.3.2(e)

Answer 39

1. elephants can trample crops so land has to be fenced off 2.legal hunting of overpopulated species is allowed at certain times which can help bring in money 2.as human population increases more homes are required as well as land for agriculture. This impacts the area of wild habitat Poaching has lowered animal population number

Question 40

how does the Terai Region manage the conflict between conservation and human needs 6.3.2(e)

Answer 40

1. forests are being cleared to make product/area for farming. However they have made alliances with governments to increase retail price of forestry products so they can leave some of the forest alone 2.improve irrigation for crops 3.use more n2 fixing plants to increase soil quality 4.multiple crops are grown on a piece of land preventing issues associated with monoculture

Question 41

what are peat bogs and what ae they used for 6.3.2(e)

Answer 41

-used as fertilisers -wetness provides anaerobic conditions

Question 42

how to conserve peatbogs 6.3.2(e)

Answer 42

-no large trees can be planted as trees remove water through transpiration -leave peatbogs as undisturbed and wet -controlled grazing to maintain plant species biodiversity

Question 43

how are humans negatively affecting the Galapagos islands 6.3.2(e)

Answer 43

-habitat destruction for building roads -deforestation of land to use for farming -increase in boats which leads to more pollution, oil spills and sewage -overfishing, collecting eggs and hunting -competition from new introduced species -introduction of new pathogens

Question 44

how to control human impacts of Galapagos islands 6.3.2(e)

Answer 44

-introduction of park rangers -limiting human access to particular island -stricter introduction on migration and introduction on animals

Question 45

how have humans impacted antarctica 6.3.2(e)

Answer 45

-global warming has melting ice sheets -whale and fish population are decreasing due to overfishing/ whaling -people dump waste into the ocean

Question 46

how have we reduced the impact on antarctia 6.3.2(e)

Answer 46

-restriciton on fishing ban on whaling -people cant dump waste

Question 47

how do people control snowdonia national park and lake district 6.3.2(e)

Answer 47

-visitors are encouraged to use paths and protect native species -litter is encouraged to be placed in bins -speed limit on boats to protect fish -snowdonia-dinowig powerstation-hydoelectric power station