ecology Flashcards
population definition
the number of organisms of the same species living in the same area
biodiversity definition
all the organisms that are interdependent on eachother and the environment in which they live eg living organisms in a rainforest
habitat definition
the area where and organism lives
community definition
the number of organisms of all the species living in the same area
decomposer definition
an organism that gains energy by feeding on dead organisms and breaking them down eg fungi and bacteria
biotic factor
living factors that may affect the distribution of organisms eg predation of mice by owls, competition for sunlight in a field of sunflowers
trophic level definition
the level of the food chain that the organism is feeding at. The producer is always at trophic level 1
food chain definition
shows what eats what in a community
food web definition
shows how food chains interact in a community
pyramid of biomass definition
shows the dry mass of individuals at each stage in a food chain
consumer definition
an organism that gains energy by eating another organism
abiotic factor definition
non living factors that may affect the distribution of plants and animals
examples of biotic factors
predation
food availability
competition
how is wind speed measured
an anemometer
how is ph measured
soil tests or a ph probe
how is light measured
light meter
how is temperature measured
thermometer
how is water/ moisture levels measured
weigh soil sample
dry sample in oven
reweigh sample
calculate change in mass
calculate the % of mass lost
how to calculate % soil moisture
change in mass/original mass X100
sampling method
-use quadrat
-place quadrat along line transect or use random sampling by throwing quadrat over the shoulder or using coordinates
-move quadrat and place at different distances
-use a key to identify species
-calculate percentage cover of species or count number of species
-record results
-repeat
what do food chains show
the feeding relationships which transfer energy and nutrients between several different organisms
what’s an issue with pyramids of numbers
they can be misleading as they don’t take size of the individuals into account 
name an advantage of pyramids of biomass over a pyramid of numbers
accounts for differing sizes of individual organisms, therefore giving a more accurate picture of energy in the ecosystem 
name an advantage of pyramids of numbers over pyramids of biomass
They are easier to calculate as you just count the number of individuals. You don’t need to kill them to calculate their dry mass and you do for biomass.
hi, is energy lost between the Sun and plant
-Light is reflected off of the leaf
-Light passes through the leaf and Mrs chloroplasts
-Light hits the ground rather than the leaf
how much energy is transferred between trophic levels?
Approximately 10 to 20%
why is energy lost in between the trophic level
-Not all food available is eaten e.g. bones and fur
-Not all food is digested as egested as faeces
-Heat and respiration, respiration provides energy for movement growth and reproduction
what is the equation for energy efficiency?
energy at tropic level/energy at previous tropic level X100
why are warm temperatures needed for decay
So that decomposers can respire aerobically to breakdown organic material
how do decomposers work?
They are saprophytic and breakdown dead organic matter by secreting enzymes onto it to digest it extracellularly and then absorb the nutrients
what are the best conditions for decomposition?
-Warm temperatures
-Adequate moisture
-Large surface area and decomposing organism
describe photosynthesis purpose in the carbon cycle
Carbon dioxide is converted into glucose and other organic carbon compounds
describe the process of feeding in the carbon cycle
Carbon transfers from plants to animals or animals to animals when eating
Describe the process of respiration in the carbon cycle
Carbon dioxide is returned to the atmosphere by plants, animals and decomposers
describe the process of decomposition in the carbon cycle
Bacteria and fungi breakdown carbon containing compound and release carbon dioxide by respiration
Describe the process of fossilisation in the carbon cycle
Plants and animals which don’t decay are preserved over a long time becoming fossil feels
describe the process of combustion in the carbon cycle
Carbon dioxide is released when fossil fuels are burned
describe the process of excretion in the carbon cycle
The process of expelling waste matter from the body eg urination
Describe the process of egestion in the carbon cycle
The process of expelling undigested foods such as faeces
describe nitrogen fixing bacteria’s role in the nitrogen cycle
-They carry out nitrogen fixation which converts nitrogen gas to nitrates
-They’re found in the soil and root nodules of legumes
-They use the glucose the plant produces as a food source and in turn, they provide the plants with nitrates to grow
describe nitrifying bacteria role in the nitrogen cycle
-These bacteria perform nitrification which converts ammonia compound in the soil into nitrates
describe the role of denitrifying bacteria in the nitrogen cycle
-These bacteria perform denitrification converting nitrates in the soil into nitrogen gas
-These bacteria like waterlogged conditions which are anaerobic
describe the role of bacteria and fungi in the nitrogen cycle
-Bacteria and fungi are decomposers
-These microbes carry out decomposition breaking down protein in dead plants and animals into ammonia.
-This is essential to maintain the cycle
what is a root hair cell?
Specialised cells in the root that are adapted for absorption by having fingerlike extensions providing a large surface area for increased absorption of water, nitrates and other minerals
how , are nitrates taken into the cell?
-Nitrates are taken into the cell by active transport
-This process requires energy
-It transports the nitrates against a concentration gradient from a low concentration in the soil to high concentration in the cell
-Cells make the energy needed for active transport during respiration
-Cells need oxygen for aerobic respiration to produce energy to move the nitrates against the concentration gradient
why is there poor plant growth in water logged soil?
-In waterlogged soil, there is less oxygen
-Meaning less respiration
-Less energy in root hair cells
-Less active uptake of nitrates
-Less protein made in plants
-Less plant growth
-Denitrifying bacteria thrives and waterlogged conditions meaning they will remove nitrates from the soil
Where are the stores of nitrogen?
-nitrogen gas
-Nitrates in the soil
-Protein in plants
-Protein in animals
why is animal manure used in fertiliser?
Nitrates are excreted from animals in their urine and egested in their faeces
Describe active uptake in aerated soils
-more oxygen in soil means
-More respiration
-More energy in root hair cells
-More active transport of nitrates
-More protein produced
-More growth
what minerals are found in fertilisers?
-nitrates
-Calcium needed for plant cell walls
-Magnesium needed to make chlorophyll
how can buying fertiliser be an investment for farmers?
Increases the crop yield
describe advantages of artificial fertilisers
-Easier to spread
-Mineral content can be controlled
describe disadvantages of artificial fertilisers
-Soil structure can deteriorate
-Easily washed off
describe advantages of natural fertilisers
-Contains organic content so add humus and structure to the soil
-Cheaper
describe disadvantages of natural fertilisers
-Smells bad and is messy
-Exact mineral content is unknown
Describe the process of eutrophication
-addition of nutrients to water from sewage and fertiliser run-off
-leads to increase in growth of aquatic plants, e.g. algae
-algae grows to form algal bloom
-algal bloom blocks the light from reaching plants that are lower down causing them to die
-The dead plants are decomposed by aerobic bacteria
-The bacteria uses up the dissolved oxygen in the water
-The fish and other animals die due to lack of oxygen
how can eutrophication be reduced?
By increasing environmental awareness of farmers to encourage better control of fertiliser and more secure storage of manure and slurry
what is leach?
The run-off into lakes
how, has the carbon cycle changed in the past 150 years?
-Increased combustion of fossil fuels add more carbon dioxide to the atmosphere
-Increase deforestation means less carbon dioxide is absorbed by plants in photosynthesis
name the effects of global warming
-Climate change
-Polar ice caps are melting
-Sea levels rise and there is flooding
-More land becomes desert
-Loss of habitats
how to prevent global warming
-Plant more trees
-renewable fuels instead of fossil fuels 
-Reduce deforestation
how does human activity damage biodiversity?
-Deforestation
-Burning fossil fuels
-Using excess fertilisers
How to slow the effects of human activity on biodiversity
-sustainable wood:
* only a small number of large trees are harvested at a time
* saplings planted so this creates reforestation
* harvesting of the same area does not happen again until medium trees have grown to become large

-International measures:
* 1997 Kyoto protocol
* Paris in 2015- 195 countries agreed to a legally binding global climate change deal to attempt to reduce global warming
