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Abiotic factors

Non-living factors in an ecosystem

Biotic factors

Living factors in an ecosystem

Percolation

movement of water through the soil to the ground water

Quadrats

Square frames used in field-work techniques

Mutualism

Organisms living closely together for mutual benefit

Random sampling

Sampling method done with quadrats

Systematic sampling

Sampling method done with belt transects

Parasite

Organism feeding on another while living together

Non-indigenous species

Organisms not naturally found in an area

Reforestation

Replanting forests after destruction

Potable

Water safe for drinking

Combustion

Process releasing carbon dioxide into the atmosphere

Photosynthesis

Process removing carbon dioxide from the atmosphere

Desalination

Producing drinking water from salty water

Chlorine

Added to water to kill pathogens

Filtration

Process to remove large solids from water

population

all the organisms of a particular species in that habitat

habitat

where an organism lives

ecosystem

the interaction of a community of living organisms with the non-living parts of their ecosystem

community

all the population of different species that live together in a habitat

interdependence

all species depend on other species in some way for survival

interspecific competition

competition between different species

intraspecific competition

competition between members of the same species

competition

the struggle between organisms to survive in a habitat with limited resources

abundance

how many organisms there are

distribution

where the organisms are

what are quadrats used for

measure abundance

what are transects used for

measure how distribution changes

what is a transect

a line through a habitat along which organisms are sampled

biodiversity

variety of living things on earth or in a particular ecosystem

why is biodiversity important

keeps ecosystem stable, we need pollinators for food, need certain species for medicine, jobs , tourism and cultural aspects

fertiliser

substance added to soil in order to supply plants with nutrients

leaching

nutrients are washed from the soil by water

eutrophication

-nutrients from fertiliser enter lakes and rivers by leaching
-stimulates rapid algae growth which blocks light from reaching plants below
- lack of light kills plants
- decomposers eat dead plant matter
- decomposers aerobically respire ( less oxygen )
- lack of oxygen kills fish and other aerobic organisms

what are the bacteria that feed on dead plants called

saprobiotic bacteria

dangers of non-indigenous species being added to habitat

spread disease, ruin ecosystem as they may outcompete indigenous species

mutualism examples

oxpeckers and hippos , cleaner fish and sharks , nitrogen fixing bacteria and plants

what percentage of energy and biomass is passed on at each stage

10

what affects rate of decomposition

oxygen availability, temperature, water content

trophic level

position of an organism in a food chain

why is only 10% of biomass passed on at each stage of a food chain

organisms don’t eat all of their food, some material isn’t absorbed, most biomass is used to release energy for processes

nitrogen cycle steps without plants and animals

nitrogen fixation , nitrification , denitrification

nitrogen cycle with plants and animals steps

nitrogen fixation , nitrification , assimilation , decomposition , nitrification , denitrification

nitrogen fixation

nitrogen fixing bacteria turn nitrogen gas into ammonium.

what can lightning do in terms of nitrogen fixation

lightning can turn nitrogen gas into nitrates

decomposition in nitrogen cycle

dead plants and animals and waste products are decomposed into ammonia

nitrification

nitrifying bacteria turns ammonia into nitrites then nitrates

denitrification

denitrifying bacteria turn nitrates into nitrogen gas

assimilation

plants take up nitrates and make proteins

water cycle

water from sea evaporates and transpiration , water vapour rises and condensed and forms clouds , precipitation , percolation

sedimentation

remove smaller bits as they pass through a bed of sand and gravel

carbon cycle

• photosynthesis takes carbon dioxide

• animals eat plants storing carbon

• plants and animals respire

• plants and animals decompose releasing carbon

• plants and animals fossilise storing carbon

• carbon is released in combustion

what are 2 carbon sinks

oceans , sedimentary rock

rate of decay

change in mass / time

decomposers

break down matter at microscopic level

detritivores

small animals that break down large matter to increase surface area for decomposers

factors affecting decay

temperature, water , availability of oxygen

how does temperature affect decay

optimum temp for enzymes

how does water affect decay rate

water is needed for essential biological processes and enzyme reactions

how does availability of oxygen

oxygen is needed for aerobic respiration

4 methods of preserving food

freezing, removing water , reducing oxygen , irradiating foods to kill bacteria

reverse osmosis

salt water moves through partially permeable membrane at high pressure

negative human impacts on biodiversity

overfishing, eutrophication by fertilisers, introduction of non-indigenous species

sustainable fishing methods

• maximum catch per year

• larger holes in nets to let small fish escape

• no fishing during breeding seasons or near breeding grounds

types of conservation and maintenance of biodiversity

conserving species, reforestation

methods of conserving endangered animals

protect habitat
breeding programs

method of conserving endangered plants

seed banks - store seeds of rare species

what are indicators of air pollution

absence of lichens or crusty lichens

indicators of clean air

blackspot fungus on roses and bushy lichens

indicator of water pollution

bloodworms and sludge worms

indicator of clean water environment

freshwater shrimps and stoneflies

Food security

Having enough food to feed a population

Biological factors threatening food security

Population , changing diets , environmental changes , pests and pathogens , conflicts , price

How do environmental changes affect food security

Extreme weather conditions and environmental changes due to climate change can cause decreased yield

How can cost affect food security

Agricultural inputs can be expensive . Costs are passed on to the consumer making food more expensive

Sustainable farming methods

Making enough food for current population while ensuring that future generations ability to make enough food isn’t affected

food web

show interdependence of ecosystem

3 types of food pyramids from producer to tertiary consumer

pyramids of number, pyramid of biomass, pyramid of energy transfer

how do changing diets affect food security

makes feeding populations more difficult. drives demand and makes food more expensive

why is the carbon cycle important

to cycle carbon which is a component of all organic molecules and to sustain life

why is the water cycle important

distributes freshwater around the world

1. nitrogen fixation

2. feeding

3. denitrification

4. decomposition

5. assimulation

6. nitrification

how does oxygen availability affect decay

increases it as oxygen is needed to respire

decomposition / decay

breaking down and digestion of biological material by organisms called decomposers

what microorganisms are decomposers

bacteria , fungi, detritus feeders

uses of decomposition

compost

what is compost

natural fertiliser which recycles materials back into the soil

what are the conditions for compost making

mesh sides to increase oxygen, moist and warm conditions generated by the decomposers, insulation

how to slow down decomposition

low temperatures, sterile conditions, vacuum pack food, dry foods

what is a sustainable alternative of fossil fuels that are non-renewable

biofuel

benefits of fishfarming

can produce lots of fish for humans in small spaces. maximises yield

negatives of fish farming

attracts predators which may get caught in nets, spread of disease in and outside fish farm, eutrophication can occur ,

if fish escape they may cause problems as they’re indigenous

how do plants take up nitrates by assimilation

taken up using active transport in root hair cell

what are nitrates used for

making amino acids and proteins , proteins are used to build plant cells

3 ways concentration of nitrates in the soil can be increased

artificial fertiliser, crop rotation, nitrogen fixing and nitrifying bacteria

how does lightning help make nitrates

the heat and pressure of lightning combines oxygen and nitrogen in the atmosphere

how could deforestation affect the water cycle

water vapour in atmosphere would decrease as there is less trees and transpiration

why might CO2 levels fluctuate in a year

during winter , trees have less leaves so less photosynthesis occurs

more fossil fuels are being burned in winter

consequence of no carbon cycle

less organic molecules for future organisms to build their biomass with as there’s finite number of atoms

how do clouds form

warm air rises with water vapour and as the air cools , the water vapour condenses