Ecology - Topic 7 (paper 2)

• Abiotic factors: The non-living aspects of an ecosystem e.g temperature, light intensity, moisture, wind direction, wind intensity, soil pH, soil mineral content, carbon dioxide levels and oxygen levels
• Adaptation: A feature of an organism that increases its chance of survival in its environment
• Anaerobic decay: Decomposition in the absence of oxygen (commonly occurring in waterlogged soils) that produces carbon dioxide and methane gas
• Apex predator: A carnivore at the top of the food chain with no predators
• Biodiversity: The variety of living organisms in an ecosystem
• Biogas: A type of biofuel (methane gas) produced by anaerobic decay in biogas generators
• Biotic factors: The living components of an ecosystem e.g food availability, pathogens, predators and other species
• Carbon cycle: The cycle through which carbon (in the form of carbon dioxide) moves between living organisms and the environment, involving respiration, photosynthesis and combustion
• Community: All of the populations of different species living together in a habitat
• Competition: When different organisms compete for the same resources (e.g light, water, mates, territory) in an ecosystem
• Compost: Dead and decaying organic matter, commonly used as a fertiliser
• Decomposers: Organisms that release enzymes which catalyse the breakdown of dead plant and animal material into simpler organic matter
• Decomposition: The breakdown of dead materials into simpler organic matter
• The rate of decomposition is affected by temperature, water and oxygen availability
• Deforestation: The removal of trees from land which is subsequently used to grow crops or provide space for cattle
• Distribution: The spread of living organisms in an ecosystem
• Ecosystem: The community of organisms (biotic) and non-living (abiotic) components of an area and their interactions
• Efficiency of biomass transfer: The efficiency of biomass transfer between trophic levels is calculated using:
• Extremophiles: Organisms that can live in extreme environments e.g high temperatures, high salinity
• Food chain: Describes the feeding relationships between organisms and the resultant stages of biomass transfer
• It takes the form: producer ⟶ primary consumer ⟶ secondary consumer ⟶ tertiary consumer
• Food security: Ensuring that populations have access to adequate amounts of safe and nutritious food
• Peat is commonly used as a garden compost
• Prey: Animals that are eaten by predators
• Water cycle: The cycle through which water moves between living organisms and the environment, involving evaporation, transpiration, condensation and precipitation
• Sustainable fisheries: Methods of harvesting fish at a sustainable rate and increasing fish stocks, for example, by controlling net size or introducing fishing quotas
• Mean: The average of a set of numbers calculated by dividing the sum of the values by the number of values
• Microorganisms: Very small organisms involved in the recycling of materials in an ecosystem
• Peatlands: Areas of peat soil in wetland habitats formed by the accumulation of partially decayed organic matter
• Quadrat: A square grid of known area used in sampling to determine the abundance and distribution of organisms in an ecosystem
• They return mineral ions to the soil and convert carbon to carbon dioxide which is released into the atmosphere
• Secondary consumers: Carnivores that consume herbivores at trophic level 3 of a food chain
• Pyramid of biomass: A table of the dry mass of living material at each trophic level of a food chain
• Sustainable: The ability to maintain something for future generations
• Mycoprotein: A food high in protein (suitable for vegetarians) that is produced by the microorganism, Fusarium , in fermentation vats
• Primary consumers: Herbivores that consume producers at trophic level 2 of a food chain
• Median: The middle number in a list of values ordered from lowest to highest
• Global warming: The gradual rise in the average temperature of the Earth due to increasing atmospheric levels of carbon dioxide and methane gas
• Trophic level: The position of an organism in a food chain
• Interdependence: The dependence of different organisms on each other for survival e.g plants depend on pollinators, herbivores depend on plants