6.3.2 - Populations and Sustainability

Question 1

What is the first phase in a population growth curve?

Answer 1

Period of slow growth, called the lag phase. Birth rate> death rate

Question 2

What is the second phase in a population growth curve?

Answer 2

Period of rapid growth, called the log phase. The population multiplies exponentially. Birth rate much greater than death rate

Question 3

What may cause a population to go from the lag phase to the log phase?

Answer 3

Breakthroughs, e.g. being able to metabolise food, genes switched on based on environment

Question 4

What is the third phase in a population growth curve?

Answer 4

Stationary phase, where overall population remains relatively constant despite fluctuations. The population reaches carrying capacity

Question 5

What is the fourth phase in a population growth curve?

Answer 5

Decline phase, where death rate > birth rate. There is a build up of waste and not enough nutrients and space

Question 6

Give examples of abiotic factors that limit population growth

Answer 6

Temperature, light, pH, availability of water or oxygen, humidity

Question 7

Give examples of biotic factors that limit population growth

Answer 7

Predators, disease, and competition

Question 8

What is immigration?

Answer 8

The movement of individual organisms into a particular area, increasing population size

Question 9

What is emigration?

Answer 9

The movement of individual organisms away from a particular area, decreasing population size

Question 10

What are density independent factors?

Answer 10

Factors that have an effect on the whole population regardless of its size. These can dramatically change population size

Question 11

Give examples of density independent factors

Answer 11

Earthquakes, fires, volcanic eruptions, and storms

Question 12

What are the two types of competition?

Answer 12

Interspecific and intraspecific

Question 13

What is the competitive exclusion principle?

Answer 13

A principle that states that when two species are competing for limited resources, the one that uses the resources more effectively will ultimately eliminate the other

Question 14

Describe stage one of a predator prey relationship graph

Answer 14

An increase in prey population provides more food for the predators, allowing more to survive and reproduce. This results in an increase in predator population

Question 15

Describe stage two of a predator prey relationship graph

Answer 15

The increased predator population eats more prey organisms, causing a decline in prey population

Question 16

Describe stage three of a predator prey relationship graph

Answer 16

The reduced prey population can no longer support the large predator population. Intraspecific competition for food increases, so predator population decreases.

Question 17

Describe stage four of a predator prey relationship graph

Answer 17

Reduced predator numbers result in less of the prey population being killed. More prey organisms survive and reproduce, increasing prey population

Question 18

What is conservation?

Answer 18

The maintenance of biodiversity through human action or management.

Question 19

What is preservation?

Answer 19

Protection of an area by restricting or banning human interference

Question 20

What is a sustainable resource?

Answer 20

Renewable source that is being economically exploited in such a way that it will not diminish or run out

Question 21

What are the aims of sustainability?

Answer 21

Preserve the environment, ensure resources are available for future generations, allow humans in all societies to live comfortably, enable less economically developed countries to develop, and create a more even balance of consumption of resources

Question 22

What is coppicing?

Answer 22

A technique for small-scale timber production whereby a tree trunk is cut close to the ground, meaning new shoots form from the cut surface and mature. Eventually, the shoots are cut and in their place more and more are produced.

Question 23

What is rotational coppicing?

Answer 23

When the woodland is divided into sections and trees are only cut in a particular section until all have been coppiced. Then, a new area is coppiced and this continues until the first area is reached again, which should have regrown fully

Question 24

What does rotational coppicing prevent?

Answer 24

Succession, as the trees never grow enough to block out light. This maintains biodiversity

Question 25

What is pollarding?

Answer 25

A technique similar to coppicing but the trunk is cut higher up so deer and other animals cannot eat the new shoots as they appear.

Question 26

What techniques can be used for sustainable fishing?

Answer 26

The use of nets with large mesh sizes, so immature fish can escape
Allowing commercial and recreational fishing only at certain times of the year
Introduction of fish farming to prevent the loss of wild species