Chapter 24 - Populations And Sustainability

Question 1

Describe a population growth curve.

Answer 1

1. Birth rate higher than death rate so population increases in size (slow growth).
2. Number of breeding individual increase so population increases exponentially (rapid growth).
3. Population is stable, may fluctuate slightly due to changes in limiting factor

Question 2

Define a density independent factor and give an example.

Answer 2

Factor that have an effect on a population regardless of its size, and can change it dramatically e.g. earthquake, fire, storm.

Question 3

Limiting factor

Answer 3

Environmental resource or constraint that limits population growth (or even causes its decline).

Question 4

Examples of limiting factors

Answer 4

Abiotic: temperature, light, humidity, pH.

Biotic: predators, disease, competition.

Question 5

Carrying capacity

Answer 5

Maximum population size an environment can support.

Question 6

Interspecific competition

Answer 6

Two different species competing for the same resources.

Question 7

Intraspecific competition

Answer 7

Members of the same species competing for resources.

Question 8

Competitive exclusion principle

Answer 8

Less well-adapted species is outcompeted.

This causes a decline in its numbers.

Can no longer exist in habitat alongside other species.

Question 9

Describe and explain a predator-prey curve.

Answer 9

1. Increase in prey population means more food for predators, which survive and reproduce.
2. This causes a decline in prey numbers.
3. Less prey results in more intraspecific competition, so there are less predators.
4. Less prey is killed, so the population increases and cycle repeats

Question 9

Describe and explain a predator-prey curve.

Answer 9

1. Increase in prey population means more food for predators, which survive and reproduce.
2. This causes a decline in prey numbers.
3. Less prey results in more intraspecific competition, so there are less predators.
4. Less prey is killed, so the population increases and cycle repeats

Question 10

Define conservation.

Answer 10

Maintenance of biodiversity through human action or management.

Includes maintaining diversity within species, genetic diversity and habitats.

Question 11

Define reclamation.

Answer 11

Restoring areas that have been damaged or destroyed with methods such as controlled burning.

Question 12

Importance of conservation.

Answer 12

1. Economic: provides resources for human survival and income e.g. clothes, medicine.
2. Social: enjoying natural beauty of nature, means of relaxation.
3. Ethical: all organisms have right to life and many are a key part of the food chain. Moral responsibility to conservs ecosystems for future generations.

Question 13

Define preservation.

Answer 13

Protection of area by restricting or banning human interference, so that the ecosystem is kept in its original state.

Question 15

Small scale sustainable timber production.

Answer 15

Coppicing: tree trunk cut close to the ground, from which new shoots grow.

Pollarding: trunk is cut higher up so animals cannot each new shoots as they appear.

Question 16

Large scale sustainable timber production.

Answer 16

Selective cutting.
Replanting trees.
Leave areas of forest for indigenous people.

Question 17

Sustainable fishing

Answer 17

Use of nets with different mesh sizes so immature fish can escape and breed.
Fish farming - prevents loss of species.
Limiting number of fish that can be caught in one area.