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How can resources be harvested sustainably?
Rate of removal < rate of replacement
Distinguish between bioaccumulation and biomagnification
Bioaccumulation- build up of toxins within an organism
Biomagnification- increase in concentration at successive trophic levels
Outline what is meant by rewilding
Allowing a previously managed area (high human impact) to revert back to its natural state
Outline what is meant by an ecological tipping point.
A critical threshold where a small amount of additional stress causes a rapid, self-reinforcing, and often irreversible shift in an ecosystem.
Define keystone species
A species that has a disproportionate effect on the structure of an ecological community.
Model ecosystems
Manipulate variables under controlled conditions
Outline the four requirements for stable ecosystems.
1. Steady supply of energy
2. Efficient nutrient cycling
3. High genetic diversity
4. Abiotic variables within zones of tolerance
Explain why the Amazon rainforest is reaching it's tipping point.
1. Deforestation
2. Reduced transpiration
3. Less rainfall
4. Drought
5. Transition from rainforest to grassland
Outline some of the impacts of plastic pollution on marine animals.
1. Choking when accidentally consumed
2. Starvation when mistaking plastic for food
3. Getting caught in plastic waste/ internal damage from ingesting plastics
Describe four factors that reduce the sustainability of agriculture.
1. Soil erosion- reduces fertility of soil
2. Nutrient depletion- soil less fertile; overuse of fertilizers
3. Monoculture- reduces genetic diversity; overuse of pesticides and herbicides
4. High carbon footprint- high energy demands
Explain how eutrophication reduces the BOD in a body of water.
1. Nutrient runoff (from fertilizer use)
2. Algal bloom
3. Less light reaching plants- reduced photosynthesis
4. Plants/ algae die
5. Increased decomposition by aerobic bacteria
5. Reduced oxygen in the water
Explain the impacts of DDT and/or mercury on an ecosystem.
1. Biomagnification
2. DDT resulted in sea birds with reduced reproductive success
3. Mercury resulted in mercury poisoning in humans (Minamata bay)