B7 Flashcards
what are the levels of organisation in an ecosystem?
individual, population, community, ecosystem
what is an ecosystem?
The interaction between the living components and the normal components
what’s factors do plant compete for?
light
space
water
mineral ions
what factors do animals compete for?
food
mates
territory
what is interdependence?
different species in an ecosystem depend on each other for various resources, if one species is removed the whole community may be affected
what is a state community?
a community in which all the biotic factors and all abiotic facts are balanced so that population sizes remain relatively constant
what are abiotic factors?
non living factors
what are the abiotic factors that may affect an ecosystem?
light intensity
temperature
moisture
soil pH and mineral content
wind intensity and direction
carbon dioxide level
oxygen level
why might light intensity affect an ecosystem?
different species of plants may have different optimum light intensity for growth
why does temperature affect an ecosystem?
Different species of plants and animals may have different optimum temperatures for growth and survival
how does soil pH affect an ecosystem system?
certain plants grow better in either alkaline or acidic soil
soil pH may affect the appearance of plant e.g. colour of hydrangea
how does moisture level affect an ecosystem?
many plants cannot survive in waterlogged soil as their roots cannot respire
certain plants are adapted to high moisture levels
how does wind intensity affect an ecosystem?
plants are more likely to germinate in locations with low wind intensity which may also attract animals that depend on plant to live nearby
how does soil mineral content affect an ecosystem?
most plants require a high level of soil minerals to grow well
what plant is adapted to low soil mineral content?
carnivorous plants that catch insects to compensate for the low level of soil mineral content
how does carbon dioxide concentration affect and ecosystem?
higher carbon dioxide concentration leads to more plant growth
how does oxygen concentration affect an ecosystem?
aquatic animals cannot survive in areas with low oxygen concentration
what are the biotic factors that may affect an ecosystem?
food
new predators
new pathogens
competition
what are adaptations?
features that enable organisms to survive in their living environment
what are organisms living in extreme environments called?
extremophiles
what are 3 examples of extreme living environments?
high temperature
high pressure
high salt concentration
where are extremophile bacteria?
in deep sea vents
what is the definition of a population?
a species that occupy the same habitat
what is the definition of a habitat?
the place in which an organism lives
what is the definition of commutity?
populations of different species interacting
what is the definition of an ecosystem?
the interactions between biotic and abiotic factors in an area
what do food chains show?
the feeding relationships of different organisms and the flow of energy between the organisms
what is the definition of biomass?
the total mass of living material
what are trophic levels?
the stages in a food chain
what do arrows in a food chain represent?
the direction of biomass transfer
what is the order of the food chain and the order of trophic levels?
producer
primary consumer
secondary consumer
tertiary consumer
what is a producer?
an organism that makes its own food through photosynthesis
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?
an organism that feeds on producers
what is a secondary consumer?
an organism that feeds on primary consumers
what is a tertiary consumer?
an organism that feeds on secondary consumers
what is a predator?
a consumer that kills and eats other animals
what is prey?
an animal that is killed and eaten by another animal
what is the pattern of predators and prey in a stable community?
the numbers of predators and prey rise and fall in cycles
what are producers the first trophic level?
producers provide all biomass for the food chain
rest of the food chain involves the transfer of this biomass
what is used to measure the abundance and distribution of organisms in an area?
a quadrat
how do materials cycle through the living and non living components of an ecosystem?
organisms take in elements from the surroundings e.g. soil, air
elements converted to complex molecules which become biomass
elements transferred along food chain
elements returned to environment during excretion and decomposition of dead organisms
what the 3 molecules which are cycled through ecosystems?
oxygen, carbon dioxide and water
what is the carbon cycle?
plants fix carbon dioxide into organic molecules during photosynthesis
the organic carbon containing molecules are passed onto organisms that eat the plants
carbon dioxide is released back into the atmosphere by respiration
burning fossil fuels releases carbon dioxide
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
what is the water cycle?
water from lakes and oceans evaporate
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
what is the role of microorganisms in cycling materials through an ecosystem?
they return carbon to the atmosphere as carbon dioxide and minerals ions to the soil
what is meant by decomposition?
the breakdown of dead materials into simpler organic matter
how do decomposers break down dead matter?
decomposers release enzymes which catalyse the breakdown of dead material into smaller molecules
what are the two of decomposition?
aerobic and anaerobic
what are the factors that affect the rate of decomposition?
Oxygen availability
Temperature
Water content
why is oxygen required for decomposition?
Most composers require oxygen for aerobic respiration
how does the availability of oxygen affect the rate of decomposition?
As oxygen levels increase the rate of decomposition increases and as oxygen levels decrease the rate of decomposition decreases
why can decomposition still occur in the absence of oxygen?
some decomposers respire anaerobically, but this means the rate of decomposition is slower as it produces less energy
How does water content affect the rate of decomposition?
decomposers require water to survive
In most conditions, the rate of decorum position is high
in waterlogged soils, there is little oxygen for respiration so the rate of decomposition decreases
why does decomposition require water?
Water is required for the secretion of enzymes and the absorption of dissolved molecules
how does temperature affect the rate of decomposition?
Decomposition release enzymes
The rate is the highest at 50° because that is a optimum temperature for enzymes
Lower temperature enzymes work too slow slowly the rate decreases
Higher temperatures enzymes in nature and decomposition stops
how is the rate of change calculated when considering the decorative biological material?
Rate of change = change in value/change in time
what is compost?
The nutrient-rich product of the rapid decay of waste biological material in optimum conditions set by gardeners and farmers
how is compost used?
Used as a natural fertiliser to promote growth of crops or garden plants
how do biogas generators work?
Bio gas generators provide methane gas for fuel through anaerobic decomposition that occurs in animal waste
how can environmental conditions affect communities?
Temperature soil pH light intensity affect the abundance and distribution of organisms within the community
How can different temperatures be bad for certain communities?
if the temperature is too low growth will be slower as organisms will use more energy to stay warm
If the temperature is too high or organisms can die and water will become unlimited as evaporation increases
How can changes 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 cannot survive with certain gases present
Polluted water can cause illness animals that drink it
what are the detrimental impacts of of sulphur dioxide on the environment?
dissolving water to form acid rain, which can errode buildings and pollute water sources
when is sulphur dioxide formed?
When fossil fuels containing impurities are burnt
what are the detrimental impacts of carbon monoxide on the environment?
Carbon monoxide binds irreversibly to haemoglobin which prevents it carrying oxygen
Too much exposure can cause unconsciousness and death
how is carbon monoxide formed?
From the incomplete combustion of fossil fuels
What are the greenhouse gases?
water vapour
Carbon dioxide
Methane
what are three human activities that contribute to greenhouse gases?
Burning fossil fuels
Deforestation
Large scale livestock farming
how do greenhouse gases lead to global warming?
Greenhouse gases allow heat from the Sun to enter the atmosphere
The gases act as a blanket and trapped the heat in the atmosphere
What are three negative consequences of global warming?
Sea levels rise caused by melting icebergs
disrupted farming and agriculture
Increased spread of disease in warmer climates
what is biodiversity?
The variety of the different species on earth or within an ecosystem
what is the importance of biodiversity?
To maintain the stability of an ecosystem
how does biodiversity ensure the stability of an ecosystem?
It reduces the dependent on particular species for resources e.g food and shelter, so that if one species is removed, other species can still survive
why have humans consumption of resources and waste production increased?
rapid rise in human population
Increase in standard of living
Where does pollution occur?
Air, land and water
what is an example of water pollutants?
Sewage
Fertiliser
Chemicals
how does eutrophication occur?
fertiliser from farms pollute the water causing access algae depleting the oxygen in the water causing other plants and animals to die
Dead plants are decomposed by bacteria and the oxygen levels decrease further
what are examples of air pollutants?
Smoke
Acidic gases
what are examples of land pollutants?
Landfill waste
Chemicals
what human activities reduce the land availability for animals and plants
Building
Farming
Quarrying
Disposing of waste
why have peat bogs been destroyed?
To produce compost to increase food production
why does the destruction of peat bogs greatly contribute to the greenhouse effect?
peat bogs are stores of carbon and burning them release a large volume of carbon dioxide into the air
why have large-scale deforestation activities occurred?
to provide land for cattle or rice fields
to grow crops to produce biofuels
What is the greenhouse effect?
Greenhouses trapped energy from the Sun as heat in the atmosphere keeping the temperature on earth suitable for life
What is causing global warming?
The increase in levels of greenhouse gases so temperature increases on earth
what are the harmful effects of deforestation?
Destruction of many animals habitats
Releases large amount of greenhouse gases
What are the consequences of global warming?
rising sea levels
melting polar caps
changing weather patterns
migration of animals to find suitable habitats
tropical diseases more common
extinction of species
what are the steps that are taken to maintain biodiversity?
Reading programs for endangered species
Protection and rebuilding of rare habitats
Replanting field margins and hedgerows in agricultural areas
Reduction of deforestation and carbon dioxide emissions
Recycling and resource resources rather than dumping waste in landfill
what is the purpose of replanting hedgerows and field margins?
There is higher biodiversity in the margins and the fields that they surround
how are trophic levels represented?
Tropic levels are represented by numbers starting from one
After one tropic levels are numbered according to how far along the organism is in the food chain
what is an Apex predator?
A carnivore with no predators
why is dry mass used for biomass?
Because the wet mass varies as a volume of water in organism varies
how do you calculate the efficiency of biomass?
Efficiency = (energy transferred/total energy available) x 100
what percentage of incident energy from light to photosynthesis do producers transfer?
1%
what percentage of biomass from one tropic level is transferred to the level above in feeding?
10%
why are biomass transfers not 100% efficient?
Energy is lost
how is energy loss through biomass transfers?
Removal of faeces (egestion)
removal of waste products e.g. urine: water and urea (excretion)
Respiration where large amounts of glucose is lost
Production of inedible bones and shells
what is a biomass pyramid?
A pyramid that shows a total dry mass of an organism at each tropic level
What is food security?
Having enough food to be able to feed a population
What are the biological factors threatening food security?
rising birth rates
Changing diets in developed countries
New pests and pathogens
Environmental changes
Increased cost of agriculture
Armed conflicts
how does intensive farming increase the production of animals
Feed animals high protein foods to increase growth
Reduce their energy loss to the environment by limiting movement and regulating their surrounding temperature
Feed animals antibiotics to prevent disease
what are the advantages of intensive farming?
Higher yield of food
More efficient
Easier quality control
what are the disadvantages of intensive farming?
Antibiotic resistance
Expensive
Ethical objections e.g. harm caused by limited movement
Biodiversity being reduced
how can fish stocks be conserved?
Control the size of gaps in fishnets to prevent juvenile fish from being killed before reaching reproductive maturity
Introducing fishing quotas
what is a transgenic organism?
An organism that has been genetically modified to contain genetic material from another source
what is an example of genetically modified foods?
Golden rice
why might crops be genetically modified?
to improve nutritional value
To be pest resistant
To be pesticide resistant
what are the advantages of golden Rice?
It contains additional beta-carotene which can be converted to vitamin A
Supplementing people who do not obtain enough vitamin A in their diet will prevent night blindness from forming
what is mycoprotein?
A protein-rich substance used to make meat substitute food for vegetarians and vegans
How is mycoprotein produced?
A fungus (fusarium) is grown on glucose syrup in aerobic conditions and the biomass is harvested and purified to get the mycoprotein
