Stability In Ecosystems Flashcards
What features do stable ecosystems have? (4)
- Efficient nutrient cycling (allows the system to be self supporting. Decomposers break down carbon compounds)
- High biodiversity (Natural selection can act on favourable alleles)
- Stability (resistance to change)
- High levels of photosynthesis (supply of energy)
The stability of an ecosystem can be investigated using a model ecosystem known as a ________
Mesocosm
Why is a mesocosm good for study the response of an ecosystem to changes in specific factors?
You can control all of the factors
What are keystone species and what is the effect of their removal?
Species that have a disproportionate effect on the structure and function of their ecosystem. Their removal can cause significant changes such as loss of other species and possible ecosystem collapse.
Name 3 keystone species and their effect.
- Sea otters: Control the population of sea urchins
- Beavers: Create a wetland habitat
- Elephants: Maintaining the grassland by preventing the growth of larger plants
What are factors that affect sustainability of agriculture
- Soil erosion
(Clearing of land which means that roots that hold the soil together are lost, which results in less stable soil. This leads to soil erosion) - Leaching and nutrient run-off
(Occurs when rainfall washes fertilizers out of the soil and into nearby bodies of water which dissolves in rainwater) - Fertilizer supply
(They are expensive and used by many farmers so the cost of fertilizers is affected by the global energy prices. Switching to organic fertilizers can reduce this) - Pollution
(Agrochemicals such as pesticides, herbicides and fungicides which improve yield but can enter natural environmental) - Carbon footprint
(Reliance on fossil fuels for transportation, machinery and the production of synthetic fertilizers which increases carbon footprint. Switching to renewable energy sources can help reduce the carbon footprint)
What is Eutrophication?
When lakes, rivers and coastal water receive artificially large inputs of nutrients
(e.g: Nitrates and phosphates) which results in excess growth of plants and phytoplankton (e.g: algae)
What is the consequence of the growth of algae, known as algae bloom.
Block out sunlight and stop it penetrating below the water surface
—> Aquatic plants below the surface of water die. can no longer photosynthesize
—> algae start to die when competition becomes too intense
—> more aquatic plants and algae die. decomposers feed on the dead organic matter
—> number of decomposers increase
—> decomposers respire aerobically. use up dissolved oxygen in water
—> Increased biochemical oxygen demand
—> availability of dissolved oxygen in water rapidly decrease
Biomagnification vs Bioaccumulation
Biomagnification: The increase in concentration of absorbed chemicals in each organisms up the food chain
Bioaccumulation: The buildup of absorbed chemicals in a single living organsim
Microplastics vs Macroplastics
Microplastics: Pieces of plastic that are less than 5 mm in length
Macroplastics: plastic over 5 mm in length, including plastic bags, bottles, food packaging and fishing nets
Human activities, such as deforestation and over-harvesting can destabilize ecosystems.
What are some restoration strategies?
- Species reintroductions
(Apex predators control the populations and keystone species can alter the structure of an ecosystem) - Limiting human influence
(E.g preventing the harvesting of resources. Controlled grazing or burning)
What is primary succession and secondary succession?
Primary Succession is when a new area of land is populated by a group of species for the first time. This land is barren with no soil. The only species that could survive in this barren land are what are called Pioneer Species.
Secondary succession happens when a climax community or intermediate community is impacted by a disturbance. This restarts the cycle of succession, but not back to the beginning—soil and nutrients are still present.
