1. Circulation of nutrients
1.1. soil
1.1.1. structure
1.1.1.1. pores inbetween particles
1.1.1.1.1. provide water and air for plants
1.1.1.2. inorganic components from rock
1.1.1.2.1. sandy
1.1.1.2.2. clay
1.1.1.2.3. loams
1.1.2. fauna
1.1.2.1. fungi
1.1.2.1.1. penicillium
1.1.2.1.2. decompose large plant molecules
1.1.2.1.3. nurtrient cycling
1.1.2.2. bacteria
1.1.2.2.1. NItrobacter
1.1.2.2.2. most abundant
1.1.2.2.3. imporant
1.1.2.3. invertebrates
1.1.2.3.1. earth worms, woodlice, spiders, nematodes
1.1.3. rhizosphere
1.1.3.1. plant roots and soil contact
1.1.3.2. many micro-organisms here
1.2. detritivores and decomposers
1.2.1. detritivores
1.2.1.1. invertebrates that feed on Detrius
1.2.1.1.1. may be eaten by a larger animal, starting a detrius based food chian
1.2.2. decomposers
1.2.2.1. bacteria, funghi
1.2.2.1.1. release digestive enzymes
1.2.2.1.2. absorb digested nutrients
1.2.2.2. utilise energy as sources of
1.2.2.2.1. energy
1.2.2.2.2. carbon
1.2.2.2.3. nutrients
1.2.2.3. cellular respiration
1.3. Decomposition
1.3.1. undecomposed matter
1.3.1.1. litter
1.3.2. completely decomposed matter
1.3.2.1. humus
1.3.3. mineralisation
1.3.3.1. nutrients from dead organisms released
1.3.4. rate
1.3.4.1. type of organic matter
1.3.4.2. number/ types of detritivores and decomposers
1.3.4.3. environmental conditions
1.4. cycles
1.4.1. carbon cycle
1.4.1.1. needed for carbohydrates, proteins, nucleic acid, lipids
1.4.1.2. moves by abiotic to biotic environment by fixation during photosynthesis
1.4.1.3. returned to atmosphere by respiration and decomposition
1.4.2. NItrogen
1.4.2.1. fixation
1.4.2.1.1. atmospheric nitrogen to ammonia
1.4.2.2. nitrification
1.4.2.2.1. ammonium to nitrite to nitrates
1.4.2.3. dentrification
1.4.2.3.1. returns nitrogen to the atmosphere
1.4.2.4. ammonification
1.4.2.4.1. decomposition
1.4.2.5. effected by water saturation
1.4.3. Phosphate
1.4.3.1. added to soil by weathering of rocks
1.4.3.2. taken up by producers, returned by decomposition
1.4.3.3. limiting factor in productivity of aqautic ecosystems
1.4.3.4. enrichment can lead to eutrophication
2. Symbiotic interactions
2.1. interaction between any species living together
2.2. parasitism
2.2.1. one organism benifits while the other is harmed
2.2.2. often a balance is acheived between the parasitic damage and the host's defence
2.2.3. relastionship may evolve to be highly specific
2.2.4. parasites
2.2.4.1. facultative
2.2.4.1.1. can live with or without host
2.2.4.2. obligate
2.2.4.2.1. cannot survive without host organism
2.2.4.3. Endoparasites
2.2.4.3.1. within hosts body
2.2.4.4. Ectoparasites
2.2.4.4.1. on surface of host
2.2.4.5. transmission
2.2.4.5.1. vectors, secondry hosts
2.2.4.5.2. direct contact
2.2.4.5.3. resistant stages
2.3. commensalism
2.3.1. one organism benifits, the other is unharmed
2.3.2. usually based on feeding
2.3.3. difficult to observe in nature
2.3.4. ie. clown fish in the tentacles of an anenome
2.4. Mutalism
2.4.1. both organisms benefit
2.4.2. both organisms share metabolites and are structirally compatible
2.4.3. ie. lichen - an interaction between fungus and alga
3. Succession
3.1. series of changes in types of species which occupy an area in a given time
3.2. at each stage of succsession the current species creates the environmental conditions suitable for its competitors
3.3. system moves from
3.3.1. unstable community --> relatively stable community
3.3.2. simple --> complex
3.3.2.1. number of species
3.3.2.2. population sizes
3.3.2.3. biological productivity
3.3.2.4. increase in variety of habitats and niches
3.3.2.5. increase in complexity of food webs
3.3.3. ecosystem may loose complexity due to
3.3.3.1. monoculture
3.3.3.1.1. diversity limited- one crop grown
3.3.3.2. toxic pollution
3.3.3.3. oxygen depleation
3.3.3.3.1. algal blooms
3.3.3.3.2. Eutrophication (more nutrient being put in that removed)
3.3.3.3.3. larger animals die
3.4. example
3.4.1. grass colonise area
3.4.2. humus builds up
3.4.3. support and nutrients increased
3.4.4. ideal conditions for tree saplings developed
3.4.5. trees grow, blocking light
3.4.6. grass out competed
3.5. autogenic
3.5.1. changes in environemntal conditions which lead to change in species are caused by the biological processes of the organisms themselves
3.6. allogenic
3.6.1. changes in environmental conditions leading to changes in species composition are unrelated to the organisms present.
3.6.2. Examples include hurricanes, forest fires and climate changes.
3.7. primary
3.7.1. plants established on land not previously inhabitated, no soil
3.7.1.1. bare rock, newly formed sand dunes
3.7.2. takes longer than secondary
3.7.2.1. due to lack of soil
3.8. secondary
3.8.1. plants invade habitat previously inhabited by other plants, existing soil
3.8.1.1. regeneration after forest fire
3.9. pioneer species (first to colonise area)
3.9.1. lichens which colonise bare rock
3.9.2. annuals who seeds are blown into a cleared field
3.9.3. can withstand difficult environmental conditions
3.9.3.1. ie. dessication (drying out)
3.9.4. fast growing, high rate of reproduction
3.10. Climax community
3.10.1. mature
3.10.2. stable
3.10.3. no further succsesion takes place
3.11. Degradative
3.11.1. changes assosiated with stages of decomposition
3.11.2. when organisms die and decompose, certain species appear
3.11.3. also known as heterotrophic succession
4. Increase in energy needs
4.1. increase in human population has led to increase in energy demand
4.2. finite fossil fuel supplies are running out
4.2.1. must be conserved
4.2.2. alternatives must be found
4.2.2.1. nuclear
4.2.2.2. solar
4.2.2.3. wind
4.2.2.4. hydroelectric
4.2.2.5. wave
4.2.2.6. geothermal
4.2.2.7. biofuels
4.3. increase in fuel use has led to global warming
4.3.1. green house effect
4.3.2. gas in the earths atmosphere prevents infrared heat from escaping, warming the earth
4.3.3. the problem gasses
4.3.3.1. carbon dioxide
4.3.3.2. water
4.3.3.3. methane
4.3.3.4. nitrous oxide
4.3.3.5. CFCs
4.3.4. this may lead to reduction in diversity
4.3.4.1. Coral bleaching
4.3.4.1.1. Coral polyps with white Calcium Carbonate exoskeleton
4.3.4.1.2. symbiotic relationship with coloured zooxanthellae
4.3.4.1.3. increase in temperatures make these zooanthellae leave the polyps
4.3.4.1.4. the white exo skeleton is left, the coral is bleached.
5. Pollution
5.1. negative effect of harmful substances in the environment
5.2. water
5.2.1. organic material
5.2.1.1. eg. dumping of sewage
5.2.1.2. food for micro-organisms
5.2.1.2.1. use up oxygen
5.2.1.2.2. make water anoxic
5.2.1.3. other naimals die
5.2.2. shown by BOD of water
5.2.2.1. Biochemical Oxygen Demand
5.2.2.2. the greater the BOD, the more micro-organisms, the more polluted the water is
5.3. concentration of pollutant increases along the food chain
5.3.1. known as biomagnification
5.3.2. DDT and heavy metal pollutants show high biomagnifictaion as they are large, persistant molecules
5.4. susceptible species
5.4.1. con not tolerate changes in the environemnt
5.4.2. indicator species eg. lichen and stonefly nymphs
5.4.2.1. dsisappearance of lichens indicates rise in SO2 levels
5.5. favoured species
5.5.1. can tolerate a wide range of conditions
5.5.2. invasive exotic species can be considered pollution
6. Energy fixation and flow
6.1. photosynthesis
6.1.1. energy fixation
6.1.2. autotrophic oorganisms
6.1.2.1. phototrophic organisms
6.1.2.1.1. light to chemical energy
6.1.2.2. chemotrophic
6.1.2.2.1. use energy from breakdown of inorganic molecules
6.1.2.2.2. make complex organic molecules
6.1.2.2.3. involved in nitrogen cycle
6.1.3. plants
6.1.3.1. autotrophs
6.1.3.1.1. store extra material
6.1.3.2. respires
6.2. respiration
6.2.1. heterotrophs
6.2.1.1. cannot synthesis energy rich molecules
6.2.1.2. consume ready made molecules
6.3. productivity
6.3.1. primary productivity
6.3.1.1. the amount of light energy converted into chemical energy during a given period of time by autotrophs
6.3.2. total primary productivity =
6.3.2.1. Gross primary productivity (GPP)
6.3.3. net primary production
6.3.3.1. energy availiable in food web
6.3.3.1.1. availiable to primary consumers
6.3.3.2. (GPP) - energy used in plant respiration (R)= (NNP)
6.3.4. measured in biomass
6.3.4.1. dry wieght of vegetation ( g/m2/year)
6.3.4.2. effected by
6.3.4.2.1. temperature
6.3.4.2.2. light intensity
6.3.4.2.3. CO2
6.3.4.2.4. nutrients
6.3.4.2.5. water
6.3.4.2.6. limiting nutrients
6.4. Energy flow
6.4.1. producers
6.4.2. Consumers (heterotrophs)
6.4.2.1. NPP availiable
6.4.2.2. herbivore
6.4.2.2.1. primary consumer
6.4.2.3. carnivore
6.4.2.3.1. secondry / tertiary consumer
6.4.2.3.2. predators
6.4.2.3.3. carrion feeders
6.4.2.3.4. parasitic
6.4.3. decomposers
6.4.3.1. bacteria and funghi
6.4.3.2. convert orginc wate into inorganic compounds
6.4.3.2.1. essential
6.4.4. food chains
6.4.4.1. arrows show direction of energy flow
6.4.4.1.1. 10% passed onto each new levels
6.4.4.2. trophic levels
6.4.4.3. ecological efficiancy
6.4.4.3.1. ratio of (NPP of one level) / (NPP of level below)
6.4.5. Pyramids of
6.4.5.1. numbers
6.4.5.1.1. typrical shape
6.4.5.1.2. inverted
6.4.5.2. biomass
6.4.5.2.1. total mass of organisms at ecach level
6.4.5.2.2. typical shape
6.4.5.2.3. aquatic ecosystems
6.4.5.3. productivity
6.4.5.3.1. typical shape
6.4.5.3.2. best
7. Biotic Interactions
7.1. Biotic
7.1.1. interactions between organisms and living factors
7.1.1.1. predation
7.1.1.2. desease
7.1.1.3. food supply
7.1.1.4. competition
7.2. Abiotic
7.2.1. between organisms and non living factors
7.2.1.1. temperature
7.2.1.2. light intensity
7.2.1.3. soil pH
7.2.1.4. water availiablity
7.3. Density
7.3.1. Dependant
7.3.1.1. regulate population growth
7.3.1.2. effects increase in proprtion to population size
7.3.1.3. ie. predation, food supply and disease
7.3.2. Independant
7.3.2.1. may regulate population growth
7.3.2.2. effects independant of population size
7.3.2.3. effect large and small populations equally
7.4. interactions
7.4.1. interspecific
7.4.1.1. individuals of a different species
7.4.2. intraspecific
7.4.2.1. individuals of the same species
7.5. Predator/ prey
7.5.1. population growth curves
7.5.2. predators lag behind prey/ slightly out of phase
7.5.2.1. predators control numbers of dominant most competetive prey species, allowing less strong populations to increase ie. grazers
7.5.2.2. grazers
7.5.2.2.1. any species which eats part of an organism without killing it
7.5.2.2.2. moderate grazing increases biodiversity
7.5.2.3. prey have adapted sos not be eaten
7.5.2.3.1. camouflage
7.5.2.3.2. warning colouration
7.5.2.3.3. mimicry
7.5.3. interactions are cyclical
7.5.3.1. recurring in cycles
7.5.4. regulated by
7.5.4.1. other predators
7.5.4.2. availiability of food for prey
7.5.4.3. disease
7.5.4.3.1. parasitism
7.6. competition
7.6.1. interferance
7.6.1.1. when two organisms fight over a resource
7.6.2. Exploitation
7.6.2.1. two or more species use the same resurce
7.6.3. exotic species are not native, ie. been introduced
7.6.3.1. may compete more succsefully than native species
7.6.3.2. may change the habitat itself, making it unsuitable for native species ie. rhodedahdron
7.6.4. weak competitors
7.6.4.1. potential for growth if ecosystem changes
7.7. niche
7.7.1. fundamental
7.7.1.1. total resources a species can make use of without competition
7.7.2. realised
7.7.2.1. actual resources a species makes use of with competition in mind
8. interactions -costs, benefits
8.1. positive
8.1.1. beneifits species
8.1.1.1. symbiosis is a relationship in which at least one species will benefit
8.2. negative
8.2.1. harms species
8.2.1.1. competition is a negative interaction for both species, neither will benifit
8.3. neutral
8.3.1. no effect on species
8.4. the nature of an interaction may change
8.4.1. parasitism
8.4.1.1. positive environemntal factors will increase hosts health
8.4.1.2. negative environmental factors will damage hosts health, favouring the parasite
8.5. managing environmental factors
8.5.1. by use of
8.5.1.1. drugs
8.5.1.2. pesticides
8.5.2. improves health and host environemnt
8.5.3. herbicides used to manage plant competition
8.6. organisms have evolved to cope with environmental changes
8.6.1. tolerance/ compensation mechanisms
8.6.2. behavioural and physiological responces
9. Effects of intensive food production
9.1. increase in population has led to increased food production
9.2. traditional farming cannot meet demands
9.3. monoculture
9.3.1. growth of one species
9.3.2. advantages
9.3.2.1. high yeilds
9.3.2.2. large profits
9.3.3. disadvantages
9.3.3.1. effect on soil condition
9.3.3.1.1. nutrients used by plan population are depleated
9.3.3.1.2. plant debris not alowed to decompose in soil
9.3.3.2. destruction of habitats
9.3.3.2.1. hedgerows removed
9.3.3.2.2. devestating effect on species diversity
9.3.3.3. large field size
9.3.3.4. breeding ground for pests
9.3.3.4.1. lack of natural predators
9.3.3.4.2. crops compete against weeds- encourgaing use of herbicides/ fungicides