F215.3.1 Ecosystems Biology Revision Cards


A Levels Biology (A2 Biology) Flashcards on F215.3.1 Ecosystems Biology Revision Cards, created by Laura Perry on 04/01/2016.
Laura Perry
Flashcards by Laura Perry, updated more than 1 year ago
Laura Perry
Created by Laura Perry about 8 years ago

Resource summary

Question Answer
Ecosystem (definition) All the living organisms and non-living components in a specific habitat and their interactions. It is a dynamic system.
Biotic factor (definition) The effect of living organisms on each other (food supply, predation, disease)
Abiotic factor (definition) The effect on non-living components on the ecosystem (pH, temperature, soil type)
Producer (definition) An organism that converts simple inorganic compounds into complex organic compounds.
Consumer (definition) An organism that gains energy from complex organic matter.
Decomposer (definition) An organism that feeds on waste from or dead organisms.
Trophic level Each feeding level in a food chain
Ecology The study if the interactions between organisms and their environment
How is energy transferred through the ecosystem? Energy is transferred through organisms consuming each other. Arrows represent the flow of energy.
How is energy transfer between trophic levels measured? Energy content of samples of organisms is measured at each trophic level. Samples are dried and weighed and then burned in a bomb calorimeter with oxygen. Energy passes to a mass of known water and temperature is then measured.
How is energy lost between trophic levels? Not all of an animal is consumed, like the bones. Not all of the animal can be digested either. Energy is used to respire and can also be lost through heat and excrement.
What is primary productivity? The rate at which plants convert light energy into chemical potential energy
What is gross primary productivity? The total quantity of energy transferred by plants from sunlight into plant tissues.
What is net primary productivity? The energy left as chemical energy after the plants have supplied their own needs by respiration
Why does NPP vary by ecosystem? Tropical ecosystems have more sunlight so photosynthesise faster, producing more energy.
How does human activity effect energy flow in ecosystems? They increase the productivity of producers (improving soil, removing pests and weeds, fertilisers). They shelter organisms from harmful environmental factors. Increasing productivity of organisms through breeding.
Community (definition) All the plants and animals that occupy a particular area.
Succession (definition) Gradual unidirectional change in a community of organisms over time.
Pioneer species (definition) Opportunistic species which rapidly exploit a sudden new opening in ground plant cover.
What is the origin? The first stage of ecological succession. There is low species diversity.
What is a climax community? The final stage of ecological succession, where species diversity is high.
Primary Succession (definition) The original area which has no living organisms or soil is present. Occurs on newly formed habitats that haven't previously supported a community.
Secondary Succession (definition) A following disturbance in the area but soil is still present. It occurs on sites that have previously supported a community (after a forest fire).
Give an example of primary succession resulting in climax community on a rock. Algae and lichens live on the bare rock. When the rock erodes and dead organisms builds up, this produces enough soil for larger plants (mosses and ferns). Larger plants succeed these plants until climax community is reached.
What is the function of a transect? (Line and belt) Line- across the habitat, record every species touching the line and their position. Belt- quadrats placed sequentially along a line transect.
What is the function of a quadrat (normal and point)? Square frame placed randomly in the habitat and species identified from this. Point quadrats- frames with long pins. Each species touching a pin is recorded, along with the number of times.
What is a decomposer? Organisms that return inorganic minerals from the bodies of dead organisms to the abiotic environment. They feed on waste from organisms, recycling materials like carbon and nitrogen. If they did not break them down, the energy and nutrients would remain in the dead organism.
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