6.3.2 - Populations and Sustainability Flashcards
What factors affect population size?
- Abiotic factors
- Biotic factors which include predation and interspecific and intraspecific competition
How do abiotic factors affect population size?
- Plants and animals are adapted to the abiotic factors within their ecosystem
- The less harsh the abiotic factors the larger the range of species and the larger the population sizes
What is interspecific competition?
- When members of different species are in competition for the same resource that is in limited supply such as habitat, food or water
- The individual better adapted to the environment is more likely to succeed in the competition.
What is intraspecific competition?
- When members of the same species are in competition for resources and a mate
- Individuals that are fitter will have more energy to perform a more impressive courtship ritual or may have fur or feathers in a better condition to attract a mate
What is predation?
The number of predators will determine the number of prey and vice versa causing predator prey cycles
What is conservation?
Maintaining biodiversity and maintaining ecosystems and habitats through active intervention
What is preservation?
Minimising human impact on an ecosystem or habitat by maintaining them in their present state
What are the 3 reasons for conservation and preservation?
- Economic
- Social
- Ethical
What are the economic reasons for conservation and preservation?
- Natural spaces often attract tourism
- Many medicines, foods, clothes and timber are sourced from natural ecosystems which would be lost if they are not conserved
What are the social reasons for conservation and preservation?
- People may rely on these ecosystems to live
- Natural spaces can provide many physical and mental benefits to people
What are the ethical reasons for conservation and preservation?
- We have a duty to protect species in unique ecosystems and maintain biodiversity
- We have a moral duty to preserve ecosystems for future generations to use and benefit from
Why is sustainable management needed?
To ensure that humans have food, shelter and infrastructure for survival without causing excessive loss of biodiversity and depletion of resources
Why are sustainable resources needed?
So that:
- Future generations will have resources
- Environments are preserved
- Humans can live comfortably
- Less economically developed countries can develop without exploiting natural resources
How is timber managed?
- As timber is removed it can be replaced by saplings
- Coppicing cuts trees close to the ground so that new stems grow and can be done on rotation
- Pollarding cuts trees near the top promoting the growth of a dense head of foliage and prevents animals eating the developing leaves
How are fish stocks managed?
- To prevent overfishing destructive methods can be banned
- Fishing quotas can be agreed between countries and fishing groups
- Only fish of a particular size can be harvested so younger fish have to be returned to maintain the breeding population
- Not allowing fishing in certain areas
- Increasing the size of the holes on nets
- Fish can be farmed either within the natural setting or separately on fish farms