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27 Cards in this Set
- Front
- Back
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Define ecosystem.
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A group of organisms which interact with each other and the surrounding environment so that matter is exchanged between the abiotic and biotic parts of the system.
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Ecosystems can be viewed as systems. What makes up these systems? Give examples.
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Inputs: sunlight, weathered rock,
Outputs: waste products, CO2 and O2 |
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Give examples of processes and stores within an ecosystem.
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Processes: photosynthesis, respiration
Stores: trees |
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In which situation does dynamic equilibrium exist?
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When the inputs and outputs of the system are in balance
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Disturbances can mean the system is not in dynamic equilibrium. What can disturbances instead produce?
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Disturbance can produce either positive or negative feedback. (Where the output is larger than input or vice versa)
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Define an open system and a closed system. Which one is an ecosystem?
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Open systems have no boundaries, i.e. energy and matter can be exchanged with the surrounding environment. (ECOSYSTEM)
In closed systems only energy is exchanged. |
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What are the two major functions within an ecosystem?
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The movement of energy through it and the recycling of nutrients within it. (Exchange of ENERGY and MATTER)
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Describe the flow of energy through an ecosystem.
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-Sunlight absorbed by chlorophyll and water and CO2 absorbed also
-Carbonates and oxygen are produced by photosynthesis -Oxygen is released into air/water, carbonates converted into starch and cellulose and used in respiration -Starch and cellulose produce thicker stems and new leaves, whereas respiration releases heat energy |
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What is gross primary productivity?
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It is the rate at which an ecosystem produces new growth, or biomass, (together with the carbonate used for respiration).
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If respiration is excluded when taking into account the rate at which an ecosystem produces new biomass, then what is the term given?
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Net primary productivity
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What is meant by abiotic?
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Inorganic matter (soil, air, water)
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What is meant by biomass?
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Biomass is all living matter(plants, algae, bacteria) calculated as total dry weight in a given area at one point in time (measured in kg/m2)
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What is gross primary productivity measured in?
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kg/m2/year ie: biomass per unit time
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Define positive and negative feedback as a whole.
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Change in one part of the ecosystem which brings apart a change in another part.
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Define respiration as the OCR textbook.
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The release of energy from carbohydrates and fats which give out carbon dioxide.
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What name is given to organisms that produce energy by fixing sunlight?
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Autotrophs or primary producers
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(Easy Q) What are autotrophs consumed by?
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Herbivores or primary consumers
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What eats herbivores in a food chain?
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Carnivores (secondary consumers)
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What eats secondary consumers (if anything)?
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Tertiary consumers
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What is the name given to both herbivores and carnivores and what does it mean?
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Heterotrophic (they cannot produce their own food)
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What is the term used to define organisms that feed on dead or decaying matter? And what are they usually in the form of?
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Saprophytes
Bacteria or fungi |
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How do saprophytes work?
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They release digestive enzymes onto decaying matter which dissolve it and then they absorb the soluble products.
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There are another type of organism that feeds on decaying matter, only larger pieces. What is the name for these organisms?
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Detritivores, such as earthworms and woodlice.
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What is a decomposer and what organisms does it encompass?
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A decomposer is an organism that breaks down material to release nutrients, principally fungi and bacteria but also earthworms and woodlice.
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What exactly produces a food chain?
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The flow of energy from one set of organisms to the next.
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Ecosystems contain two types of food chain. What are they and what do they mean?
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Grazing and detrital food chains
Grazing starts with a primary producer on the first trophic level. Detrital starts with detritivores(decomposers). |
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