4A,B,C,D Ecology & the Environment Flashcards
Define the term population
A group of organisms of the same species in an area
Define the term community
A group of organisms of different species in an area
Define the term ecosystem
The organisms + the environment
Define the term habitat
A place where an organism lives
TRIPLE ONLY
Define the term biodiversity
The variety of genes, species and habitats
Describe the difference between biotic and abiotic factors
Biotic = living factors
Abiotic = non-living factors
Give 3 examples of biotic factors
Predation
Competition
Disease
Give 3 examples of abiotic factors
Light intensity
Temperature
Humidity
What does the term abundance mean
The number of organisms
Describe how to estimate the population size of an organism in an area using a quadrat
Randomly lay quadrat
ID organisms using a key
Count number of individuals
Record abiotic factors e.g. …?
Repeat several times
Calculate mean and then times by total area
Explain how to avoid bias when sampling in biology
Randomly place quadrat
(i.e. use random number generator to get coordinates for placement)
Explain how to increase reliability when sampling
Increase sample size - place more quadrats down
TRIPLE ONLY
What does the term distribution mean in biology
Where organisms are located
TRIPLE ONLY
State what piece of equipment you would use to measure how the distribution of organisms change from one area to another
Line transact
TRIPLE ONLY
Describe how you would measure how the distribution of an organism changes
Lay line transect from one area to another (must be specific where)
Place quadrat at even intervals along transect (e.g. every 5m)
ID organisms using a key
Count number of individuals
Record abiotic factors e.g…?
Repeat line transect several times
Define the term trophic level
Stage in a food chain
Define these food chain terms:
Producer
Consumer
Decomposer
Producer = makes own food using photosynthesis
Consumer = needs to eat other organisms to get nutrition
Decomposer = breaks down decaying matter to get nutrition
What do all food chains start with, and give common examples
All start with producers e.g. plants, algae
How much energy is transferred from one stage in a food chain (trophic level) to another
Just 10%
Explain why energy is lost as you move along food chains
Energy released for heat, movement, release of faeces
Not all parts of organisms are eaten either e.g. bark of trees
Describe how carbon is released into the atmosphere during the carbon cycle
Combustion of fuels
Respiration of plants, animals, decomposers
Volcanic activity
Describe how carbon is absorbed from the atmosphere in the carbon cycle
Photosynthesis
Dissolving in oceans
TRIPLE ONLY
State the role of nitrogen-fixing bacteria in the nitrogen cycle
Turns atmospheric nitrogen (N2) into nitrogen compounds in soil and plants
TRIPLE ONLY
State the role of decomposers in the nitrogen cycle
Break down large nitrogen compounds into ammonium compounds
TRIPLE ONLY
State the role of nitrifying bacteria in the nitrogen cycle
Convert ammonia into nitrites and nitrates
TRIPLE ONLY
State the role of denitrifying bacteria in the nitrogen cycle
Converts nitrates back into atmospheric nitrogen (N2)
TRIPLE ONLY
Explain the role of lightning in the nitrogen cycle
Atmospheric nitrogen (N2) reacts with oxygen in the air to form nitrates in the soil
TRIPLE ONLY
Explain why it is important for atmospheric N2 to be fixed into nitrogen compounds for organisms to use
Used to make amino acids and DNA
State two main pollutant gases
Sulphur dioxide (SO2)
Carbon monoxide (CO)
State the biological consequences of sulfur dioxide
Forms acid rain - dissolves leaves and makes lakes acidic, killing fish
State the biological consequences of carbon monoxide
Binds to haemoglobin
Less oxygen transported to cells, so less respiration
Leads to fatigue, dizziness and can lead to death
State 5 greenhouse gases
Methane
Carbon dioxide
Water vapour
Nitrous oxides
CFCs
Explain what is meant by a greenhouse gas
Traps heat in the earth’s atmosphere
List the activities that have increased the number of greenhouse gases in the atmosphere
Burning fossil fuels
Cutting down trees
Increased cars, factories etc
Cattle farming and rice fields (releases methane)
Explain the main effects that too many greenhouse gases can have on the planet
Climate change and extreme weather
Desertification
Ice caps melting, causes sea level rise and flooding
Affecting animal migrations
Explain why sewage in waterways can kill aquatic life i.e. fish
Sewage provides nutrients for bacteria to grow
Bacteria grow, respire and use up oxygen in water
No more oxygen in water kills fish (water becomes anoxic)
Describe the process of eutrophication
Fertiliser/nutrients flow into water i.e. pond
Algae on surface grow
Algae block sunlight for underwater plants
Plants die (cannot photosynthesise)
Bacteria feed on plants and respire, using up oxygen in water
No oxygen kills fish
Explain what leaching is
Fertilisers dissolve in rainwater and drains into rivers, ponds and lakes
TRIPLE ONLY
Describe 4 effects of deforestation on the environment
Leaching → mineral ions aren’t taken up by roots so wash away in rainwater
Soil erosion → no roots to stabilise soil, leads to land slides
Evapotranspiration → less trees to recycle water vapour by transpiration
Carbon dioxide → less trees means less photosynthesis so less carbon dioxide absorbed from atmosphere
