Ecosystems

what does ecosystem mean ?

an ecosystem is made up of all the living organisms that interact with one another in a defined area, and also the physical factors present in that region

how can an ecosystem be desribed

as dynamic

what abiotic features could have an affect on an ecosystem

• light

• tempurature

• water availability

• oxygen availablity

• edaphic (soil) factors

how does light effect ecosystems 

• the greater the availabilty of light, the greater the success of a plant species 

• in areas of low light they may have larger leaves 

• might develop photosynthetic pigmes that require less light, or reproductive systems that operate only when light availabilty is at an optimum 

how does temperature effect ecosystems 

• effects enzyme controlling metabolic reactions 

• plants will develop faster in warmer temperatures 

• can trigger migration, hibernation, leaf fall, dormancy and flowering 

how does water availabilty effect ecosystems

• a lack of water leads to stress, which can lead to death

• a lack of water will cause plants to wilt

• xerophytes have developed ways to work around low water

how does oxygen availability effect ecosystems

• fast flowing cold water contains high conenctrations of oxygen

• if water becomes too warm, or slow flow, leads to a drop in oxygen concentration leading to suffocation of water species

• in water logged soil the air spaces between the soil particles are filled, which reduced the oxygen availabiliy

how does edaphic factors effect ecosystems

different soils have different particle sizes:

• clay- fine paritcles, easily waterlogged and forms clumps when wet

• loam- different sized particles, retains water but dosent become water logged

• sandy- coarse well sperated particels that allow free drainf, does not retain water easily

what is meant by community

all the populations that live in a particular place at the same time

what is meant by a population

all the organisms of the same species living together in a particular habitat

what is a niche 

the role an organism has in an ecosystem , including where it lives and what it eats 

what is a pioneer

a plant species found in the early stage of succession

what i meant by interspecific competition

individuals of more than one species attempt to make use of the same scarce resource

what is an autotroph 

an organism producing its own food from simple inorganic materials 

what is a heterotroph

an organism obtaing food by feeding on organic matter

what is intraspecific competition

individuals of the same soecies attempt to make use of the same scarce resources

what similarities are there between aquatic and terrestrial ecosystems

• organisms are intwedependent on each other

• variety of species found in community

• populations found at different trophic levels

• organims have specifc adaptations for their conditions

what  differences are there between aquatic and terrestrial ecosystems

• aquatic have more stable tempuratures 

• oxugen levels lower in aquatic 

• light more variable in aquatic

• water readily availble in aquatic 

• visocity of aquatic greater

• terrestrial influenced far more by gravity 

how do ecosystems work ?

• organisms require a source of energy to live - this energy is transferred through an ecosystem , linearly through biotic components

• chemical elements are also needed, theses cycles in ecosystems between biotic and abiotic components

what does chemosynthesis mean

organic compounds by bacteria or other living organisms using energy derived from reactions using inorganic chemicals

what is a chemoautotroph

• an organism that takes inorganic chemicals and transforms it into energy

which two diagrams can be used to represent energy transfer

• food webs

• food chains

what three types of ecological pyramids are there 

• pyramid of numbers: number + area

• pyramid of biomass: fresh or dry- madd +area 

• pyramid of energy:energy + area + time 

what is meant by biomass

the dry mass of an organisms

what is a producer

an organism that converts light energy into chemical energy by the process of photosynthesis

what is a consumer

an organism that obtains its energy by feeding on other organisms

how would you calculate biomass at each trophic level 

biomass present x mass of fresh material 

• however the presence of water can make this equation unreliable 

what does ecological efficieny refer to

the effecicency with which biomass of energy is transferred from one trophic level to the next

why do producers only convert a very small amount of sunlight they recievve into chemical energy 

• not all of the solar energy available is used for photosynthesis 

• water availability limits photosynthesis 

• a proportion of the enrgy is lost, as it is used for photosynthetic reactions 

what are some advantages of using biomass pyramids

• eliminates most inversion and scale problems

• solar input can be included

• can be inverted

• compares productivity due to time factor incorporated

what are some disadvantages of using biomass pyramids

• can be difficulr to draw the differences between numbers of producers and top carbivores can be huge

• biomass may not be equivalent to energy values

why is it that consumers at each trophic level convert 10% of the biomass in their food to their own organic tissue ?

• not all of the biomass of an organism is eaten

• some energy is transfered to the environemnt as metabolic heat

• some parts of organisms are eaten but are indigestible

• some energy is lost from animal via poo and wee

what is the equation for ecological efficeincy 

energy or biomass available after the transfer/ energy or biomass available before the transfer x 100

what do energy flow diagrams show ?

• the quantity of energy entering different parts of an ecosystem + what happens

• allow you to compare efficiencies of energy transfers

• allows you to compare productivity of different ecosystems

what are the 3 types of ecological productivity definitions

• Gross primary productions

• net primary productions

• secondary production

what is meant by gross primary productivity ?

rate at which plants convert light to chemical energy/ organic matter e.g rate of photosynthesis

what is meant by Net primary production 

the rate at which carbohydrates accumulated in the tissue of plants of an ecosystem 

how do you calculate NPP

NPP= GPP- R (respiratory losses)

what is secondary productivity

the rate at which energy is used to make new consumers

how would you calculate energy consumption

c=P+R+U+F

p= secondary production

r= respiration

u= energy in urine

f= energy in faceces

how to humans maximise energy input ?

Provide water and fertilisers, use selective breeding for fast growth/ provide vitamins and minerals, use selective breeding for fast growth

how to humans maximise growth?

provide good quality feed/ use optimum planting distnace between crop plants, provide light in greenhouses on overcast days

how do humans control disease

use fungicides, use antibiotic and vaccines

how do humans control predation 

use extensive systems such as ranching, contorl predators such as wolves and foxes, use intensive farming, keep animals protected from predators in sheds, used fencing to exxlude grazers like rabbits and deer, use pesticides to kill nematodes slugs and snails 

how to humans reduce competition

control competitors such as rabbits and deer/ use plughing and herbicides to kill weeds

hwo do humans reduce energy loss 

breed plants that maximise enrgy sotrgae in edible products such as seeds and fruits/ keep animals im heated sheds to recstrict movement 

how do you use a bomb calorimeter

• each sample is dried to a constant mass in an oven and then burned in oxygen in a bomb calorimeter

• the heat energy produced by oxidation passes to a knwon mass of water and the tempurature ruse of water is measured

what is a decomposer

they secrete enzymes onto detritus and digest materials externally, (fungi and bacteria)

what is a detritivore

ingest detritus, shred it and digest internally

maggots, woodlice and termites, worms and slugs (if they have mouths)

explain the process of extra cellular digestion 

• carbohydrates, protease and lipase enzymes leave the cell via exocytosis 

• hydrolysis reaction takes place which brakes down the large insoluble molecules to small soluble molecules 

• the small soluble molecules can be absorbed using carrier proteins for facillitated difussion and active transport 

• the molecules are then used in metabloism of the decomposer 

what facotrs affect decomposotion

no oxygen

incorrect temperature

what are the bitoic components of the nitorgen cycle

• chlorophyll

• amino acids

• phospholipids

• ATP

what are the abitotic components pf the nitrogen cycle

• atmosphere

• NO3- soil nitrate

• NH4+- soil

• NO2 - soil nitrate

• urea - CO (NH2)2

what are the names of the 4 process in the nitrogen cycle

• Nitrogen fixation 

• Decomposition and ammonification 

• nitrification 

• denitrification 

which bacteria is used in the nitrogen fixation between N in air and in leguminous plants 

Rhizobium 

what is an example of a bacteria used in nitrogen fixation of bacteria

Azotobacter

which bacteria is used in the oxidation between ammoniums ions and nitirte ions

nitrosomonass

which bacteria is used in the oxidation by bacteria between nitrites and nitrates

nitrobacteria

what role does fungi play in the nitrogen cycle 

nitrogen fixation

what is a nitrogen fixing bacteria

microorganisms that convert N2 into NH3 for plants

mutualism

both species benefit from the interaction in an inderpendent relatioship

chemoautotroph

a microrganism that turns inorganic chemicals into energy and use that energy to reproduce and grow

nitrifying bacteria 

can convert toxic ammonia from organic waste into nitrates 

denitrifying bacteria

breaks down nitrates and return nitrogen gas to the air

what does ammonification mean

the name given to the process by which decompsoers convert nitrogen containing molecules into dead organisms

where can CO2 be found

• the atmosphere

• in solution

• within organisms

• carbonate rocks

• fossil fuels

what are the main 7 stages of the carbon cycle 

• photosynthesis 

• feeding 

• death, excretion, egestion 

• deposition 

• resperation 

• combustion 

• oxidation 

what does primary siccession mean 

this occurs on an area of land that had been newly formed or exposed such as bare rock. There is no soil or organic materials to begin with 

what does scondary succession mean

this occurs on areas od land where soil is present by it contains no plant or animal species

what are the main steral stages

pioneer community, intermediate community and climax community