T7 organisation of an ecosystem Flashcards
define population
species that occupy the same habitat
define habitat
place in which an organism lives
define community
populations of different species interacting
define ecosystem
interactions between biotic and abiotic factors in an area
what do food chains show
feeding relationships of different organisms and the flow of energy between the organisms
define biomass
total mass of living material
what are trophic levels
stages in a food chain
what do arrows in a food chain represent
direction of biomass transfer
describe a simple food chain
producer > primary consumer > secondary consumer > tertiary consumer
what is a producer
organism that makes its own food
what types of organisms are primary producers
photosynthetic organisms like green plants and algae that trap energy from the sun
what is a primary consumer
organism that feeds on producers
what is a secondary consumer
organism that feeds on primary consumers
what is a tertiary consumer
organism that feeds on secondary consumers
what is a predator
consumer that kills and eats other animals
what is prey
animal that is killed and eaten by another animal
describe the pattern of predators and prey in a stable community
number of predators and prey rise and fall in cycles
why are producers the first trophic level
provide all biomass for the food chain (production of glucose via photosynthesis)
rest of the food chain involves the transfer of this biomass
piece of apparatus used to measure the abundance and distribution of organisms in an area
quadrat
piece of apparatus used to study the distribution of organisms across a gradient
belt transect
describe how materials cycle through the living and non-living components of an ecosystem
organisms take in elements from their surroundings
elements converted to complex molecules which become biomass
elements transferred along food chains
elements returned to environment during excretion and decomposition of dead organisms
give 3 molecules which are cycled through ecosystems
oxygen
carbon dioxide
water
describe the carbon cycle
plants fix CO2 into organic molecules during photosynthesis
organic carbon-containing molecules are passed onto organisms that eat the plants
CO2 is released back into the atmosphere by respiration from animals and plants
burning fossil fuels also releases CO2
why is the carbon cycle important
carbon-containing molecules such as glucose are important for living organisms to grow and provide energy for vital functions within cells
describe the water cycle
water from lakes and oceans evaporates
evaporated water condenses into clouds and returns to earth as precipitation
water from precipitation is useful for life on land
water then returns to rivers and oceans through surface runoff
why is the water cycle important
living organisms require water and the water cycle provides organisms on land with a continuous supply of water
why are microorganisms important for the cycling of materials through an ecosystem
return carbon to the environment by releasing CO2 through respiration while they decompose dead matter
decomposition of dead matter in soil returns mineral ions to the environment for other organisms to use
what is meant by decomposition
breakdown of dead materials into simpler organic matter
how do decomposers break down dead matter
release enzymes which catalyse the breakdown of dead material into smaller molecules
two types of decomposition
aerobic decomposition (with oxygen) anaerobic decomposition (not w oxygen)
what factors affect the rate of decomposition
oxygen availability
temperature
water content
why is oxygen required for decomposition
aerobic respiration
how does the availability of oxygen affect the rate of decomposition
as O2 levels increase, rate increases
as O2 levels decrease, rate decreases
why can decomposition still occur in the absence of oxygen
some decomposers respire anaerobically however, rate is slower as anaerobic respiration produces less energy
how does soil water content affect the rate of decomposition
decomposers require water to survive
in moist conditions, rate is high
in waterlogged soils there is little oxygen for respiration so the rate decreases
why does decomposition require water
water is required for secretion of enzymes and absorption of dissolved molecules
how does temperature affect the rate of decomposition
decomposers release enzymes:
rate highest at 50C
lower temp, enzymes work too slowly, rate decreases
higher temp. enzymes denature, decomposition stops
how is the rate of change calculated when considering the decay of biological material
rate of change = change in value / change in time
value is a measurable variable associated with the decay of the material
what is compost
nutrient-rich product of the rapid decay of waste biological material in optimum conditions set by gardeners and farmers
how is compost used
natural fertiliser to promote growth of crops or garden plants
describe how biogas generators work
provide methane gas for fuel through anaerobic decomposition that occurs in animal waste
describe how environmental conditions affect communities
affect the abundance and distribution of organisms within communities
eg. rising global temp have been linked to extinction of frog species
how can different temperatures be bad for certain communities
temp too low = growth will be slower as organisms will use more energy to stay warm
temp too high = organisms can die and water will become limited as evaporation increases
how can change in water levels affect ecosystems
animals may have to migrate to find water
melting ice caps may destroy the habitats of some animals
how can atmospheric gases affect ecosystems
some organisms can’t survive when certain gases are present
polluted water can cause illness to animals that drink it
what impacts can sulfur dioxide have on the environment
formed when fossil fuels containing impurities are burnt
sulfur dioxide can dissolve in water to form acid rain which can erode buildings and pollute water sources
what impacts can carbon monoxide have on the environment
formed from the incomplete combustion of fossil fuels
binds irreversibly to haemoglobin which prevents it from carrying oxygen
too much exposure can cause unconsciousness and death
name 5 greenhouse gases
water vapour carbon dioxide nitrous oxide methane CFCs
give 3 human activities that contribute to greenhouse gases
burning fossil fuels
deforestation
large scale livestock farming
how do greenhouse gases lead to global warming
allow heat from the sun to enter the atmosphere
gases act as blanket and trap the heat in the atmosphere
3 consequences of global warming
sea level rise due to melting icebergs
disrupted farming and agriculture
increased spread of diseases in warmer climates
