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Species: group o organisms tt can interbreed and produce fertile offspring e.g. lion
Habitat: environment in which species normally lives or location o living organism e.g. wetlands
Population: group o organisms o same species who live in same area at same time e.g. population of mice
Community: group o populations living and interacting with each other in an area e.g. deer, owls, and bears living in the same area of a forest
Ecosystem: community and its abiotic environment e.g. fresh hydro ecosystem
Ecology: study o relationships b/twn living organisms and b/twn organisms and their environment e.g.
Distinguish between autotroph and heterotroph
- e.g. autotroph -> algae
- heterotroph -> human/cat/dog etc
Distinguish between consumers, detritivores and saprotrophs.
- e.g. consumers: lion
- detritivores: earthworms
- saprophytes: yeast
Describe what is meant by a food chain, giving 3 e.g., each with at least three linkages (four organisms)
- food chain shows the linear flow /direction of energy flow from one species to another.
- E.g. an arrow from A to B means that A is being eaten by B = indicates the direction of the energy flow.
Describe what is meant by a food web
- Shows complex interactions between species within a community/ ecosystems
- shows all the feeding relationships in a community with arrows which show the direction of the energy flow
Define trophic level
Trophic level: the trophic level of an organism is its position in the food chain.
Producers, primary consumers, secondary consumers and tertiary consumers are examples of trophic levels.
- defines the feeding relationship of that organism to other organisms in a food.
- note: some animals may be more than one trophic level depending on differing food chains e.g. could be 3 or 4
light is the initial energy source for almost all communities
Explain the energy flow in a food chain
- energy losses b/twn trophic levels include material not consumed or material not assimilated + heat loss bc cell respir
- Producers get energy fr sun (light) of photosynthesis.
- Energy flows from producers to primary consumers, to secondary consumers, to tertiary consumers..
- Energy is lost between trophic levels in the form of heat through cell respiration, feces, tissue loss and death.
- Some of this lost energy is used by detritivores and saprotrophs.
- also lose energy in the form of heat through cell respiration.
are never 100% efficient
Explain reasons for the shape of pyramids of energy
- Pyramid shows flow energy fr one trophic lvl to next in community·
- Units are energy per unit area per unit time, kJ m-2 yr-1·
- model shows the typical loss of energy from solar radiation through the various trophic levels·
- causes a tapering of the model·
- narrowing shape illustrates the gradual loss of energy progressing along the links of a food chain to higher tropic levels·
- e.g. lots of protozoa, less mosquito larvae, less carp, few pike
Explain that energy enters and leaves ecosystems, but nutrients must be recycled.
- energy enters and leaves ecosystems but nutrients must be recycled·
- Energy is not recycled.
- Constantly being supplied to the ecosystem through light energy fr sun
- Energy is lost from the ecosystem in the form of heat through cell respiration./ lost in feces, tissue loss and heat·
- Nutrients must be recycled as there is only a limited supply of them. ·
- They are absorbed by the environment, used by organisms, recycled and then returned to the environment.
- Producers (autotrophs) take inorganic molecules and convert them to organic compounds.
- consumers take in, upon death, recycled by saprotrophic bacteria and fungi (decomposers) for nutrients
- e.g. nutrients like Carbon, nitrogen and phosphorus
saprotrophic bacteria and fungi (decomposers)
Saprotrophic bacteria and fungi recycle nutrients (organic molecules) of dead organisms
Draw and label a diagram of the carbon cycle to show the processes involved
(interaction living organis and biosphere through photosyn, cell resp, fossilization, combustion)
size arrows important
details carbon cycle ***
- Photosynthesis by terrestrial plants and algae (freshwater and oceans) in which atmospheric (and dissolved ) carbon dioxide is removed and fixed as organic compounds such as carbohydrate, lipid and protein.
- Respiration by all organisms in which they metabolise organic molecules releasing carbon dioxide.
- Feeding, in which the carbon of organic molecules is move from one link in the food chain to another.
- Fossilization in which carbon as organic molecules becomes trapped in sediment as coal. gas and oil.
- Combustion during the burning of fossil fuels and burning of biomass.
Analyse the changes in concentration of atmospheric carbon dioxide using historical records
- atmospheric co2 monitored at mauna loa observatory (MLO) since 1958
- trends in atmospheric gases are studied as indicators of potential climate change(greenhouse gases)
- annual variation in co2 levels (peaks early spring after winter = least photosyn, lowest late fall after summer greatest photosyn) = seasonal variations co2 by land plants, partic northern hemisphere forests
- overall upward trend increase in co2 since 1958
- prior 1880, atmospheric co2 pret constant
- incre at 2 ppm
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