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| A group of organisms that can interbreed and produce fertile offspring. |
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| The environment in which a species normally lives, or the location of a living organism. |
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| A group of organisms of the same species who live in the same area at the same time. |
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| A group of populations living and interacting with each other in an area. |
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| A community and its abiotic environment. |
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| The study of relationships between living organisms and between organisms and their environment. |
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| An organism that synthesises its organic molecules from simple inorganic substances. |
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| An organism that obtains organic molecules from other organisms. |
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| An organism that ingests other organic matter that is living or recently killed. |
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| An organism that ingests non-living matter. |
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| An organism that lives on or in non-living organic matter, secreting digestive enzymes into it and absorbing the products of digestion. |
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| Describe what is meant by a food chain, giving three examples, each with at least three linkages (four organisms). |
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Definition
- only real examples should be used from natural ecosystems
- A -> B indicates that A is being eaten by B, ie. the arrow indicates the direction of energy flow
- each food chain should include a producer and consumers, but not decomposers
- named organisms should be used at either species or genus level
- common species names can be used instead of binomial names
- general names such as tree or fish should not be used |
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| Describe what is meant by a food web. |
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Definition
| The elaborate interconnected relationships within an ecosystem based on feeding and energy transfer. |
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Definition
| The position that an organism occupies in a food chain or a group of organisms in a community that occupy the same position in food chains. |
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| Deduce the trophic level of organisms in a food chain and a food web. |
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Definition
| Place an organism at the level of producer, primary consumer, secondary consumer and so on (as the terms herbivore and carnivore are not always applicable). |
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| Construct a food web containing up to 10 organisms, using appropriate information. |
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Definition
- only real examples should be used from natural ecosystems
- A -> B indicates that A is being eaten by B, ie. the arrow indicates the direction of energy flow
- each food chain should include a producer and consumers, but not decomposers
- named organisms should be used at either species or genus level
- common species names can be used instead of binomial names
- general names such as tree or fish should not be used |
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Definition
| Is the initial energy source for almost all communities. |
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| Explain the energy flow in a food chain. |
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Definition
- energy losses between trophic levels include:
1. Material not consumed.
2. Material not assimilated (bones, feathers, skin - not eaten).
3. Heat loss through cell respiration. |
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| State that energy transformations... |
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Definition
| are never 100% efficient. |
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| Explain reasons for the shape of pyramids of energy. |
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Definition
- energy pyramids illustrate the quantity of energy within the biomass of each trophic level
- only a portion of energy in any level is transferred to the next, commonly being 10-20%
- of the plant biomass consumed by a typical herbivore:
1. 50% is not assimilated: lost as faeces (indigestible cellulose).
2. 35% is assimilated but lost as heat during cellular respiration.
3. 15% is consumed and assimilated and incorporated into the biomass. |
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| Explain that energy enters and leaves ecosystems, but nutrients must be recycled - ENERGY. |
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Definition
- Earth constantly loses much of its incoming energy as it reflects light and radiates heat to space
- Producers consume only about 1% of solar energy available to them into organic matter during photosynthesis; thus, about 99% of solar energy never enters, and thus leaves an ecosystem without ever being converted to the energy contained by organisms
- Generally, the total energy entering an ecosystem equals the total energy lost to the environment
1. Such an ecosystem would be stable.
2. In earlier stages of succession, an ecosystem captures more energy than it loses, converting the excess into increasing biomass.
3. When an ecosystem is disturbed, it might lose more energy to the environment than it gains, decreasing in total biomass. |
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| Explain that energy enters and leaves ecosystems, but nutrients must be recycled - NUTRIENTS. |
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Definition
- Earth does not exchange significant amounts of matter with space
- Therefore, the total quantity of matter on Earth is static
- Ecosystems recycle their nutrients
1. Producers use nutrients in their environment, many of which have been formed by decomposition.
2. Consumers use the nutrients gained from the organisms they eat.
3. Decomposers break down nutrients from the organisms they decompose, making simple compounds in the environment available to producers
- Recycling requires energy |
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| State that saprotrophic bacteria and fungi (decomposers)... |
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