section 8 - ecology and the environment Flashcards
what is a habitat
the place where an organism lives
population
all the organisms of one species in a habitat
what is a community
all the different species in a habitat
what is an ecosystem
all the organisms living in a particular are and all the non-living conditions
what is biodiversity
the variety of different species of organisms on earth, or within an ecosytem
why is high biodiversity important
makes sure that ecosystems are stable because different species depend on each other for things like shelter or food.
what is reducing biodiversity
human actions like deforestation, pollution and global wearing
what are 2 abiotic factor which affect communities
- environmental conditions
- toxic chemical (eutrophication)
what are the biotic factors that affect communities
- availability of food
- number of predators
- competition
how much energy is lost between trophic levels
around 90%
what does the the 10% of total energy available for
biomass
how is energy lost
- some parts are eaten (bone) so the energy isn’t taken in
- some parts are indigestible so pass through organism and come out as waste
- a lot of energy used in respiration and stalling alive for life processes
- most transferred to surroundings by heat
what does interdependent mean
if one species changes, it affects all the others
what are the 7 important points of the carbon cycle
- green plants use carbon from CO2 to photosynthesise
- eating passes the carbon compounds in the plant along to animals in a food chain
- respiration releases CO2 back into the air
- plants and animals eventually die and decompose
- decomposers release enzymes which catalysers the break down of dead materials into smaller molecules
- fossil fuels are made from decayed plant and animal matter burned in combustion and released CO2 into the air
- CO2 gets released from respiration of the decomposers
what happens in the nitrogen cycle
- nitrogen is needed for making proteins for growth
- plants get their nitrogen from the soil, so nitrogen in the air has to be turned into nitrogen compounds before plants use it. animals can only get proteins from eating plants.
how to measure the rate
the change in the time
what is nitrogen fixation
turning N2 from the air into nitrogen compounds in the soil so plants can use
how do nitrogen from the air go to the soil
lighting
nitrogen fixing bacteria
what are the 4 different types of bacteria in nitrogen cycle
decomposers - break down proteins and urea and turn into ammonia
nitrifying bacteria - turn ammonium ions in decaying matter into nitrates (nitrification)
nitrogen-fixing bacteria - turn atmosphere N2 into nitrogen compounds that plants can use
Denitrifying bacteria - turns nitrates back into N2 (no benefit)
what does fossil fuels if they are burnt without enough energy supply produce
carbon monoxide
what does burning fossil fuels release
carbon dioxide and sulphur dioxide
what does the sulphur dioxide become
sulfur impurities
what goes this gas form when mixes with rain clouds
sulphuric acid which falls as acid rain
what is the main cause of acid rain
internal combustion engines in cars and power stations
what does acid rain cause
changes pH in rivers and many organisms are sensitive.
can kill tres and releases toxic substances from the soil making it hard for the trees to take up nutrients
how does human activity cause lots of co2
- humans release co2 into the atmosphere all the time as part of out every day lives
- people cut down large areas of forest for timber and to clear land for farming
how does human activity cause methane
- produced naturally from various sources - rotting plants in marshland
- rive growing and cattle rearing
how does human activity cause nitrous oxide
- naturally by bacteria in soils and the ocean
- a lot more is released from soils after fertilisers are used
- vehicle engines and industry
how does human activities cause CFCs
- man0made chemicals. powerful greenhouse gases
- most countries have agreed not to produce them because it damages the ozone layer that prevents UV radiation
- some still remain and get released like from leaks from old fridges
what happens in eutrophication
- nitrates and phosphates are put into fields as mineral fertilisers
- if too much fertilisers is applied and it rains afterward, nitrates are easily leached into rivers and lakes.
- the result of eutrophication which can cause serious damage to river and lake ecosystems
- another cause is pollution by sewage. contains lots of phosphates from detergents. it also contains nitrates from urine and faeces.
