Module 6 - Populations and sustainability

Question 1

3 phases of the population growth curve

Answer 1

Period of slow growth: birth rate exceeds death rate so population grows
Period of rapid growth: population esxpands exponentially and there are no restrictions
Stable state: limiting factors stop further growth leading to a stabilised population
The graphs is an S (sigmoid) shape

Question 2

Carrying capacity

Answer 2

The maximum population size an ecosystem can sustainably support. Atp, birth and death rates equalise although it can fluctuate slightly, environmental conditions can decrease population size

Question 3

Biotic, abiotic, density-dependent and density-independent factors

Answer 3

Biotic: competition, predation and disease
Abiotic: availability of light, water and space
Density-dependent: impact increases as population size increases like comp. for resources
Density independent: impact remains constant regardless of population size and can lead to extinction (natural disasters)

Question 4

2 types of migration

Answer 4

Immigration: increase in population size as organisms move into an area
Emigration: decrease in population size and organisms leave an area

Question 5

2 types of competition

Answer 5

Interspecific: occurs between different species for resources
Intraspecific: occurs within the same species for resources
Follows survival of the fittest principle

Question 6

Predator-prey relationships

Answer 6

Increase in prey=more food for predators so predator population increases and vice versa
Lack of prey=less food for predators so population decreases and vice versa

Question 7

Typical adaptations of predators

Answer 7

Sudden bursts of speed, stealth, camouflage and better prey detection (sharp vision)

Question 8

Typical adaptations of prey

Answer 8

Mimicry, protective features like spines, camouflage and better predator detection (broader vield of vision)

Question 9

Conservation

Answer 9

Resources remain available for future generations and habitats are preserved.
Management: humans control use of resources and their replenishment
Reclamation: humans restore damaged ecosystems for future use

Question 10

3 reasons for conservation of ecosystems

Answer 10

Economic: they provide resources for local and global trade, helps provide economic stability
Social: offer recreational and aesthetic value, can enhance quality of life and well-being
Ethical: all organisms have a right to exist, we have a moral responsibility to protect

Question 11

Aims of sustainability

Answer 11

1. preserve environment
2. make resources available for future generations
3. allow humans to live comfortably
4. support economy in LDCs
5. achieve more balances comsumption of resources

Question 12

Advantages of sustainable forest management

Answer 12

Improves conservation, soil and water management, more employment and income, provides sustainable wood fuel sources and secures biodiversity

Question 13

Coppicing, rotational coppicing and pollarding (small-scale sustainable forestry)

Answer 13

C: cutting trees close to the ground to allow stumps to regrow
RC: coppicing different areas sequentially to allow them to recover
P: cut trunk higher up to protect new shoots being eaten by animals

Question 14

Sustainable forestry on a large scale

Answer 14

Selective cutting: only removing the largest trees
Leaving some areas to protect livelihoods of indigenous communities
Space out plantings to reduce competition
Replanting native tree species to maintain biodiversity and water and nutrient cycles

Question 15

Sustainable fishing techniques

Answer 15

Fishing quotas
Fish farming to conserve wild populations but still provide protein
Seasonal fishing restrictions (less during breeding season to allow them to recover)