what is ecology
the name given to the study of relationships between organisms and their environment
what is an ecosystem
it is all the living organisms which interact with each other in a defined area
a community of organisms and the habitat in which it lives
the two types of factors which effect an ecosystem
abiotic
biotic
abiotic factors
NON LIVING
light availability
rainfall
soil ( edaphic)
ph
biotic factors
LIVING factors
number of predators
food availability
infectious diseases
what is a trophic level
stage in a food chain made up of particular organisms
( producers, primary and secondary consumers etc)
what does a food chain and food web show
the transfer of biomass and energy through organisms in an ecosystem
levels of a trophic level
producer
primary consumer
secondary consumer
tertiary consumer
quaternary consumer
there is rarely anymore as there is nor sufficient biomass and stored energy left to support organisms
what is a producer
what is a consumer
producer is an organism which converts light energy into chemical energy via photosynthesis
what is a decomposer
an organism which breaks down dead organisms and waste material they release nutrients back into the ecosystem
what is biomass
the mass of living material present in a particular place or particular organisms
net production formula
gross production - respiratory losses
efficiency formula
efficiency =
biomass transfer/biomass intake x 100
what is decomposition
a chemical process in which compounds are broken down into smaller molecules
why are decomposers saprotrophs
because they obtain their energy from dead or waste materials
what are detritivores
an animal which feeds on dead organic material,
explain the nitrogen cycle
- nitrogen fixation
this is when bacterias ( azotobacter and rhizobium) which contain the enzyme nitrogenase combine with nitrogen and hydrogen producing ammonia - nitrification
this is an oxidation reaction where nitrifying bacteria oxidise ammonium compounds into nitrites and nitrobacter oxidise nitrites into nitrates - denitrification
this converts nitrates into the soil back into the nitrogen gas
this is done under anaerobic conditions - ammonification
decomposers convert nitrogen containing molecules in dead and waste materials into ammonium compounds
explain the carbon cycle
fluctuations in the atmospheres carbon dioxide
what is succession
the process by which an ecosystem changes over time
what are the two types of succession with definitions
primary succession
this occurs in an area of land which has been newly formed or exposed, there is no soil or organic material
secondary succession
occurs on areas of land where soil is present but no plants or animals are there
stages of succession
- barren land
new bare land with hostile abiotic conditions - pioneer community
colonisation of pioneer species to form a pioneer community which appear from seeds/ spores blown in on the wind and adapt to survive in hostile conditions, they change the abiotic conditions by forming humus through decomposition making it less hostile. - intermediate conditions
this is when previous species are outcompeted as the new species are better adapted so soil compositions continue to change and an intermediate community develops new species continue to change the environment making it less suitable for the previous species - climax community
biodiversity increase forming a climax community
what is deflected succession
succession prevented by human activity because of grazing and trampling of vegetation, removing existing vegetation to plant vrops, burning of forest clearance
what does distribution of organisms refer to
where individual organisms are found within an ecosystem
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Neuronal Communication65
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Hormonal Communication43
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Homeostatis62
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Plant Response34
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Energy For Biological Processes23
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Respiration29
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Genetics Of Living Systems27
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Patterns Of Inheritance And Variation58
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Manipulating Geonomes17
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Cloning And Biotechnology29
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Ecosystem29
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Population And Sustainability20
