Ecology

Question 1

Ecology

Answer 1

The study of interactions among organisms and their environment

Question 2

Size

Answer 2

Number of individuals living in an area. Determined by BR and DR

Question 3

Density

Answer 3

Measurement of population per unit area. Affected by immigration and emigration

Question 4

Dispersion

Answer 4

Spread of population, can be clustered, random or uniform

Question 5

Biotic potential

Answer 5

In pop ecology, the natural reproductive potential of species. This has evolved through time and is related to survival rates. Mammals tend to have a smaller number of off spring as their rate of ‘survivorship’ is high, although they can be vulnerable to increase DR.

Question 6

Environmental resistance

Answer 6

Term used to explain mortality rates controlled by environmental factors that prevent survival.

Question 7

Density independent

Answer 7

(Increase death rate whatever pop size)Natural disasters are an example of density independent environmental limiting factor as they will increase the DR whatever the pop size

Question 8

Density dependent

Answer 8

(Depends how many people are in an area) Such as food supply/disease will become more prevalent limiting growth as pop size/density increases.

Question 9

Biotic

Answer 9

Living factors e.g. parasites

Question 10

Abiotic

Answer 10

Non-living factors e.g. food/water

Question 11

Exponential growth

Answer 11

Rapid/unrestricted growth

Question 12

Logistic growth

Answer 12

Reach potential then growth rate slows

Question 13

How has humanity grown through exponential phase

Answer 13

Human pop has overcome much of environmental resistance that was limiting growth- In past 200 years we have been through a log phase of exponential growth through development and technology

Question 14

Lag phase (graph)

Answer 14

There is a high BR/DR with low life expectancy so replacement rate is consistent

Question 15

Exponential phase (graph)

Answer 15

Improvements in technology, food supplies and medical care which reduce disease and overcome environ resistance

Question 16

Stationary phase (graph)

Answer 16

There is more family planning, lower infant mortality and improved contraception

Question 17

Overpopulation characteristics

Answer 17

Low income per capita/poverty
Unemployment 
Outward migration
Insufficient food/energy resources 
Prone to natural disasters 
War/conflict

Question 18

Underpopulation characteristics

Answer 18

High income per capita
Low unemployment
Inward migration
Good living conditions
High levels of tech

Question 19

Overpopulation

Answer 19

Too many people in an area relative to available resources. This reduces standard of living, so with no technology advances only a fall in pop will raise living standards

Question 20

Underpopulation

Answer 20

Too few people to use the resources efficiently for a given level of tech. Suggests an increase in pop would mean a more effective use of resources/increased standard living for all

Question 21

Optimum population

Answer 21

Ideal balance between population/resources. Pop size in a given area which working with all resources will give the highest standard of living for those living there. Maximising income per capita and is a balance that nations will try to achieve through direct/indirect management

Question 22

Carrying capacity

Answer 22

Max pop size that an area/environment can sustain indefinitely- flexible depending on averg lifestyle

Question 23

Ecological footprint

Answer 23

A measure of the demand placed by humans on Earths natural resources

Question 24

Overshoot

Answer 24

An ecological term referring to a point when the population and its associated consumption of resources exceed the long term carrying capacity of the environment

Question 25

Total productivity bio-capacity

Answer 25

All the food, water and energy resources produced by the Earths natural systems annually to sustain us

Question 26

Implications of carrying capacity and ecological footprint

Answer 26

This introduces a limit to pop growth- global pop growth is starting to slow down forming an S shaped curve as it adjusts carrying capacity. This is known as the logistic model of pop growth which suggests that as pop size increases, rate of increase declines as more environmental resistance is encountered-leading to equilibrium pop size fixed by carrying capacity

Question 27

Easter island

Answer 27

Approx. 1000 years ago Polynesians settled on the island and over 600 years society grew and thrived in this resource plentiful land- pop peaked at several thousand. Up to 16 mil trees cut down or burned, stone was quarried to build houses/statues. Over half a millennium later James Cook visited the island and found only 700 islanders living marginal lives.