6.3.2- Populations and Sustainability

Question 1

what is the expected population size at the end of the century?

Answer 1

11.2 billion

Question 2

what is carrying capacity?

Answer 2

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

Question 3

what is a limiting factor?

Answer 3

the factor that limits the rate of population growth because it is the factor that is in the shortest supply

Question 4

what are the two limiting factors and give examples of them?

Answer 4

-abiotic factors= temp, light, pH, water/oxygen availability, humidity
-biotic factors= competition, predators, disease

Question 5

what does the lag phase of the typical population growth curve show?

Answer 5

-slow growth
-individuals acclimatising to their habitat
-low reproductive rate

Question 6

what does the log/expodential phase of the typical population growth curve show?

Answer 6

-rapid growth
-plenty of resources and good conditions
-fast reproductive rate
-low mortality rate

Question 7

what does the stationary phase of the typical population growth curve show?

Answer 7

-zero population growth, stable state
-population size levels out at the carrying capacity
-further growth prevented by limiting factor
-reproductive rate=mortality rate

Question 8

what other 3 factors effect the population size and what do these mean?

Answer 8

-immigration= movement of individuals into a particular organism
-emigration= movement of individual organisms away from a particular area
-density independent factors= factors that have an effect on the whole population size regardless of its size (eg- volcano eruptions, earthquakes)

Question 9

what is the equation for population growth?

Answer 9

pop change during period/pop at start of period x 100

Question 10

what are the two types of competition and what do these mean?

Answer 10

-interspecific= between individuals of different species
-intraspecific= between individuals of the same species

Question 11

what is a niche?

Answer 11

the role of a species within it’s habitat, consisting of both it’s biotic interactions

Question 12

what is an example of interspecific competition in the UK and why did this occur?

Answer 12

red vs grey squirrel
-grey squirrel introduced in UK
-can eat a more variety of food and so can store more fat
-increases survival and its ability to reproduce

Question 13

is the relationship between predator and prey interlinked?

Answer 13

yes

Question 14

what does the graph that shows predator-prey relationships look like?

Answer 14

peaks and troughs of the prey population are mirrored by peaks and trough of the predator population, after a time delay.

Question 15

how many stages of the predator-prey relationship are there?

Answer 15

4

Question 16

what happens in stage one of the predator-prey relationship graph?

Answer 16

increase in prey population provides more prey for predators, allowing more to survive and reproduce, and so predator population increases

Question 17

what happens in stage two of the predator-prey relationship graph?

Answer 17

the increased predator population eats more prey organisms, causing a decline in the prey population, and so the predator population increases

Question 18

what happens in stage three of the predator-prey relationship graph?

Answer 18

the reduced prey population can no longer support the large predator population, and so intraspecific competition for food increases, resulting in a decrease in the size of the predator population

Question 19

what happens in stage four of the predator-prey relationship graph?

Answer 19

reduced predator numbers results in less of the prey population being killed, so more prey organisms survive and reproduce, increasing the prey population

Question 20

what is conservation?

Answer 20

the maintenance of biodiversity through human action or management.

Question 21

what is sustainable development?

Answer 21

the management of ecosystems so that the natural resources within them can be used without running out

Question 22

what is reclamation?

Answer 22

the process of restoring ecosystems that have been damaged or destroyed

Question 23

what is preservation?

Answer 23

the protection of an area by restricting or banning human interference, so that the ecosystem is left in its original state

Question 24

what are the three important reasons for conservation?

Answer 24

-economic reasons
-social reasons
-ethical reasons

Question 25

explain the economic reasons for conservation?

Answer 25

-to provide resources that humans need to survive and to provide an income
-eg- rainforests supply resources for medicinal drugs, clothes and food that can be traded

Question 26

explain the social reasons for conservation?

Answer 26

-people enjoy natural beauty
-people use areas for activities which are beneficial to health by providing a means of relaxation and exercise

Question 27

explain the ethical reasons for conservation?

Answer 27

-organisms have a right to exist and play an important role within ecosystem
-moral responsibility for future generations to conserve the wide variety of existing natural ecosystems

Question 28

what is a sustainable resource?

Answer 28

a renewable resource that s being economically exploited in such a way that it will not diminish or run out

Question 29

what are the 5 aims of sustainability?

Answer 29

-preserve the environment
-ensure resources are available for future generations
-allow humans in all societies to live comfortably
-enable LEDCs to develop through exploiting their natural resources
-create an more even balance in the consumption of these resources between MEDCs and LEDCs.

Question 30

what is coppicing?

Answer 30

a small scale timber production, to produce sustainable timber?

Question 31

what occurs during coppicing?

Answer 31

-tree trunk cut close to ground
-new shoots form from cut and mature
-shoots are eventually cut and more grow in their place
-these shoots have multiple uses

Question 32

what does rotational coppicing involve?

Answer 32

-woodland divided into sections and tress only cut in particular section until all have been coppiced
-begins in another area, allowing for new to grow
-process continued until reached first coppiced, which would have now grown to mature sized trees

Question 33

what does rotational coppicing do?

Answer 33

maintains biodiversity

Question 34

what is pollarding?

Answer 34

technique similar to coppicing, but trunk is cut higher so animals cannot eat the new shoots as they start to appear

Question 35

what is felling trees an example of?

Answer 35

large scale timber production

Question 36

what are the 5 ways that timber companies ensure felling is sustainable?

Answer 36

-practise selective cutting
-replace trees through replanting
-plant trees at an optimal distance to decrease competition
-manage pests and pathogens to maximise yields
-ensure that areas of forest remain for indigenous people

Question 37

what are ways in which fishing has been made sustainable?

Answer 37

-fisheries policy, limit on the fish being caught in a particular area
-large mesh fishing nets, so only adult fish can be caught
-allowing commercial and recreational fishing only at certain times
-fish farming