9) Ecosystems Flashcards
What is an ecosystem made up of?
Abiotic and biotic parts
What are the levels of ecosystem organisation? (3)
Individuals
Populations
Communities
What are communities made up of?
Populations from different species
What are populations made up of?
Individual organisms to make up a single species
What do plants compete for? (4)
Water
Mineral ions
Light
Space
What do animals compete for? (3)
Food
Mates
Territory
What is interdependence?
One species relying on another species for different things
What do species rely on other species for? (4)
Shelter
Seed dispersal
Food
Pollination
When is a community stable?
When all the species and environmental factors are balanced and population sizes are more or less constant
What are the levels of the food chain? (5)
1) Producer makes its own food through photosynthesis (algae, plants)
2) Primary consumers
3) Secondary con sumers
4) Tertiary consumers
5) Apex predators
What do food chains show?
The feeding relationships within a community
What components are food chains made up of? (4)
Predators
Prey
Apex predators
Decomposers
What are decomposers?
The final stop for food chains, they break down dead material by secreting enzymes
Enzymes partially digest waste products and produce small food molecules
What are apex predators?
Predators which are not prayed upon
What are prey?
Animals predators eat
What are predators?
Consumers that eat other animals
What does a trophic level describe?
Where an organism fits into a food chain
What is at level 1 of the food chain?
Producers that use light energy to synthesise their own food
What is at level 2 of the food chain?
Primary consumers that eat plants/ algae (herbivores)
What is at level 3 of the food chain?
Secondary consumers that eat herbivores (carnivores)
What is at level 4 of the food chain?
Tertiary consumers that eat other carnivores
What do predator-prey graphs show?
The cyclical nature of predator and prey populations in stable communities
What is the process of a predator-prey graph?
1) An increase in prey numbers means more food is available for predators so predator numbers increase
2) The increase in predator numbers means the prey have more predators so the prey numbers decrease
3) The predators then have less food available so their numbers decrease
4) The decreasing predator numbers allows the prey numbers to increase again, and the cycle repeats
What is parasitism?
One organism benefits from the relationship but the other is harmed
What is mutualism?
Both species benefit in this relationship
What are the types of relationship between species? (4)
Predator-prey
Producer-herbivore
Mutualism
Parasitism
Why is the recycling of materials essential for future organisms?
They provide the building blocks
What does the water cycle describe?
How water moves on, or above or below the surface of our planet between different locations
What is the carbon cycle?
1) Carbon is removed from the atmosphere by producers who use it in photosynthesis
2) Animals obtain carbon compounds by consuming plant matter
3) Carbon is returned into the atmosphere because of respiration in plant and animal cells
4) When animals and plants die, decomposers return the carbon locked in their bodies back to the atmosphere via decay
5) Combustion of fossil fuels is another source of carbon entry into the atmosphere
What is the nitrogen cycle?
Nitrogen is present in all living organisms
It moves through food chains and is recycled when organisms die
What is the process of the nitrogen cycle?
1) Plants absorb nitrates from the soil and grow with the help of bacteria in roots (root nodule bacteria)
2) Plants absorb nitrogen from the air
3) Farmers may add fertilisers with root nodule bacteria to add nitrates to infertile soil
4) Nitrogen passed onto animals that eat the plants
5) Plants and animals die and bacteria recycle nitrogen back into soil through decomposition
6) Lightning strikes soil and nitrogen is released back into the air
What type of bacteria helps plants absorb nitrogen in the soil?
Root nodule bacteria
What is the process of the water cycle?
1) Water evaporates from the Earth’s surface and rises to the atmosphere
2) Water vapour in atmosphere cools and condenses to rain or snow
3) Rain or snow will become surface run off or ground water
4) Plants take up water through their roots
5) We get drinking water by filtering or adding chemicals to fresh water or by desaltinating seawater
What is responsible for recycling organic matter within an ecosystem?
Decomposers
What do decomposers produce?
Compost
How do decomposers break down dead materials?
Secreted enzymes partly digest waste products by producing small and soluble food molecules which can diffuse into the decomposer
What factors affect the rate of decay? (3)
Temperature
Oxygen availability
Moisture availability
What are the types of decomposers? (2)
Fungi
Bacteria
What methods are used to preserve food by decreasing the rate of decay? (5)
Freezing Storing in another gas Storing in oil Irradiating Salting
How does storing food in another gas slow the rate of decay?
Low/ no oxygen availability stops aerobic respiration
How does irradiating food lower the rate of decay?
Radiation kills decomposers
What does the temperature and milk decay practical measure?
The effect of temperature on milk by measuring pH change
What is the process of the decay of milk practical? (4)
1) Use a water bath to heat all of the components to a given temperature
2) Mix the milk, sodium carbonate and Cresol red to create a purple solution
3) Add lipase to the solution and start timing
4) When solution turns yellow stop timing
5) Repeat using different temperatures
What is the independent variable of the milk decay practical?
Temperature
What is the dependent variable of the milk decay practical?
Time taken for solution to turn yellow
Why are lipase and sodium carbonate used in the milk decay practical?
To speed the slow decay
What indicator is used in the milk decay practical?
Cresol red
What substances are added in the milk dceay practical? (4)
Milk
Cresol red
Lipase
Soidum carbonate
What is biomass?
The total number of living material in an organism multiplied by the number of organisms
How is the relative amount of bioamss at each trophic level in a food chain represented?
A pyramid of biomass
Why is less energy and biomass passed onto to the higher food chain organisms?
Energy is wasted at each trophic level
What is the general rule for transfer efficiency between trophic levels?
10% available to next trophic level
How much light energy do producers trap?
1%
What are reasons for inefficient transfer of biomass? (4)
Movement
Digestion
Excretion
Body temperature
Why does movement waste biomass transfer energy?
Large quantities of glucose are used to produce energy
Highly mobile animals require a lot of energy to sustain movement meaning less energy for growth
Why does digestion waste biomass energy transfer?
Not all food is digested
Some food is stored as the waste material faeces
Why does excretion waste biomass energy transfer?
Some material is excreted such as carbon dioxide, water and urea
What are quadrats?
Square frames used to estimate population sizes
What are transects?
A piece of tape that is stretched across the habitat of interest
What are transects used to do?
Investigate the effect of a factor on the distribution of a species
What is the median?
Middle value
What is the mode?
Most common value
What is the mean?
Average value
What metrics are used for organism abundance?
Mean
Mode
Median
What is the process of using quadrats to estimate a population size?
1) Divide habitat into series of quadrat sized cells
2) Randomly select a given number of cells and go out into the habitat and place a quadrat in these positions
3) To evaluate count the number of individual organisms of interest or record the percentage of the quadrat taken up by an organism
4) Samples from the quadrat are used to estimate the total population of a given area
What is the equation for population using quadrats?
population = number counted x (total survey area / area sampled)
Why can’t most animals be sampled with quadrats or transects?
They are mobile
What is the method of estimating the animal population size of an area?
Capture-recapture
Animals are caught, marked and then released
How are crawling insects and birds caught?
Pooters and nets
What can slurry be used as?
Fertiliser
What fungus is grown to produce Mycoprotein?
Fusarium
What has led to the decline of many fish stocks across the globe?
Overfishing
What is correlation?
A relationship or connection between things
What is causation?
When a change in one factor is the reason for a change in another factor
What type of sampling should be used when assessing ecosystems?
Random sampling
Why have warning signs against a lack of biodiversity been ignored?
Pursuit of economic gain
What is an attitude shift to biodiversity causing?
Measures taken to prevent further damage being done
What does industrial waste affect? (3)
Water
Air
Land
How is water contaminated by industrial waste?
Sewage and toxic chemicals find their way into water sources
What are some land pollutants?
Toxic herbicides and pesticides
Buried nuclear waste
Household waste in landfill sites
What gas cause acid rain?
Sulfur dioxide
What is deforestation?
The cutting, clearing and removal or trees in order to free up land for biofuels as well as cattle and rice fields
What are negative consequences of deforestation?
Methane release
Carbon dioxide release
Loss of ecosystem services
Loss of biodiversity
Why does deforestation increase carbon dioxide release?
Less photosynthesis is taking place
What are consequences of global warming? (7)
Migration patterns
Rising sea surface temperatures bleach sensitive corals
Ocean acidification makes it harder for corals to build their skeleton
Increased extreme meterological events
Distribution of species
Melting ice causing rising sea levels
Reduction of biodiversity
What are pros and cons of fish farming?
Pros- reduces the pressure of overfishing on wild fish populations
Cons- parasites, diseases and excess nutrients can leak into the surroundiung environment
What is eutrophication?
When nutrient levels in a body of water increase
What does eutrophication cause?
Improved growth in nutrient poor environments
Increases in algae which are toxic to many species
What are invasive species?
Species that are not native to a habitat but have been introduced by humans
What is a con of invasive species?
They outcompete native species and cause a loss of biodiversity
When will food security be achieved?
When the whole global human population has access to enough safe and nutritious food to stay healthy
What are obstacles to food security? (6)
Birth rates Conflicts Costs of agricultural inputs Diet shifts New pests and pathogens Extreme meterological events
What programmes attempt to reduce the negative impacts humans have on biodiversity? (5)
Breeding programmes
Regeneration of rare and threatened habitats
Government-imposed targets
Recycling waste
Incentivising farmers to maintain fiel margins
What can an indicator species signal?
The levels of a specific environmental condition by being present or absent
What do lichen species indicate?
Levels of air pollution
What do the different species of lichen mean?
Bushy lichen need really clean air
Leafy lichen can survive a small amount of air pollution
Crusty lichens can survive in more polluted air
Where do blacksport fungus grow?
Roses if there is a low concentration of sulfur dioxide
What are uses of sampling indicator species?
Cost effectice and simple way of measuring pollution levels
Early indication of environmental changes
Not very precise
What do different species in water show?
Bloodworm and sludgeworm can live in highly polluted water
Freshwater shrimp and stonefly can only live in clean water
