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radiation from the sun is the source of energy for most comunities of living organisms . green plants and algae absrob a small amount of the light that reaches them . the transfer from light energy to chemical energy occurs during photosynthesis . this energy is srored in the substances that make up the cells of the plants . plants are ..... and are eaten by ....... which are .......
- producers
- consumers
- animals
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the mass of living material (...) at each stage ina food chain is .... than it was agt the previous stage . the biomass at each stage can be drwan to scale and shown as a ...... ... ......
- biomass
- less
- pyramid of biomass
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draw a food chain containing a snail , grass and a bird
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the snail is a
primary consumer
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the bird is a
secondary consumer
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the amounts of material and energy contained in the biomass or organisms is reduced at each succesive stage in a food chain because : (2)
- 1) some materials and energy are always lost in the organisms waste materials
- 2) respiration supplies all the energy needs for living processes , including movement . Much of this energy is eventually transfered to the surroundings
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ecology is the study of :
how organism interact with their environment
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organisms are affected by :
their physical environment and by other organisms which share the same habitat
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pysical factors can also be called :
- abiotic factors
- or
- non-living factors
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1) the physical factors , which influence the environment include:
2) these can be measured over .....
- 1)
- temperature
- rainfall
- light
- availibility of oxygen
- carbon dioxide
- etc
- 2)
- time
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often it is ..... of a factor , eg highest or lowest temperature , which determine where an organism can live
extremes
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biotic factors are :
those which involve interations between living organisms e.g. competition or the prescene or parasites or disease organisms
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the different species which interact within the habitat are called the :
community
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the individuals of specific species make up a :
poulation
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the term ecosystem describes :
the habitat , the community which lives there and the physical factors which which influence it
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some ecosystems are fairly self conatined because :
only a gew animals move in and out and food is produced mainly within the ecosystem
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a pond or a forest are examples of such a :
closed ecosystem
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examples of an open ecoystem include :
an estuary
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open ecosystems recieve :
from outsied and many of the animals are visitors rather than rsidents
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organisms in an ecosystem can be divided into :
- producers
- primary consumers
- secondary consumers
- tertiary consumers
- decomposers
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producers - green palnts and algae which ..... to form .... .... as food , which is then available to other members of the community
- photosynthesize
- chemical energy
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primary consumers (1st consumers) - ...... , which feed on the ...
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secondary consumer (2nd consumer) - ..... , ..... wich eat .....
- carnivores (predators and carnivores could be the other way round)
- predators
- herbrivores
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tertiary consumer (3rd consumer) - the ... .... which eat other ....
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name a tertiary consumer which we could add the food chain we drew
cat
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food chains show :
which organism eat other organisms
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explain the following food chain A -> B -> C
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in a food chain the arrows always :
go the way of the food and the energy
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food chains always begin with .... .... (producers) which provide food for the ...
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radiation from the sun is the source of ...... for all .... . green plants capture a small part of the solar energy which reaches them and store it in ..... which make up thier ..... and ...
- energy
- communities
- substances
- cells
- tissues
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food webs consist of :
interconnected food chains which show the complex feeding relationships whicm may exist in an ecosytem (altthough some animals only eat one kind of food)
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in a food web , some organisms are usually found at more than one ..... ... (..... ....) they may , for example feed as both primary and secondary consumers , if they eat both plants and aniamls
trophic level (feeding level)
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in a food chain the organisms at the bottom of the chain are are often more ....... than those at the top the width of the band represents the number or organisms at each trophic level
below is a pyramid of numbers
numerous
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sometimes , however a pyramid of numbers looks different e.g. a single oak tree may have hundreds of caterpillas feeding on it
in this case it is more useful to consider :
- the mass of organisms at each trophic level , called the biomass . this produces a pyramid of biomass
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16% of energy gained from the grasshopers food became part of the grasshoppers body however 1% of energy gained from the rabbits food became the rabbist body explain why
as both are primary consumers the difference is not due tom diet . But the rabbit is a mammal and therfore warmblooded therfore it uses energy to maintain its body temperature which the grasshopper as an inverterbrate does not need to do
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energy is transferred from plants to the environment during respiration . in what form is this energy ?
heat
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