Ecosystems Flashcards
What is the difference between a community and a population?
A population is all the organisms of a particular species living in the same area whereas a community is all the interdependent populations of organisms in an area
What forms an ecosystem?
Organisms and the environment where they live
What is the calculation for an estimate for a population size from a quadrat?
POPULATION SIZE = NUMBER OF ORGANISMS IN ALL QUADRATS X TOTAL SIZE OF AREA/TOTAL AREA OF QUADRATS
What are some examples of abiotic factors?
- pH
- Temperature
- Oxygen levels
- Light intensity
What are 2 examples of biotic factors?
- Competition
- Predators
What does a food web show?
The feeding relationships between the organisms in a community
What is the difference between an organism, population, community and ecosystem?
- Organism - a single living organism
- Population - all the organisms of the same species in an area
- Community - all the populations in an area
- Ecosystem - all the living organisms (the community) and the non-living components in an area
What is a pollutant?
Energy or a chemical substance that has a harmful effect on living organisms
What might plants compete for?
- Light
- Space
- Water
- Nutrients
What might animals compete for?
- Food
- Mates for reproduction
- Territory
Why do very few plants grow beneath a canopy?
Very little sunlight so plants unable to compete with trees for sunlight
What is intraspecific competition?
Same species competing for the same resource
What is interspecific competition?
Members of different species competing for the same resource
What is a niche?
The role of a species within a particular ecosystem
Around how much energy does the Earth capture from the Sun via photosynthesis each year?
3X10^20 joules
What is the energy flow in organisms?
PRODUCER -> PRIMARY CONSUMER (HERBIVORE) -> SECONDARY CONSUMER (CARNIVORE)
What are trophic levels?
Feeding levels
What is a parasite?
An organism that feeds on another organism (host) while they are living together which harms the host but benefits the parasite
What is mutualism?
When 2 organisms live closely together in a way that benefits them both
Describe the mutualism between a shark and small fish
- The cleaner small fish benefit by getting food
- Shark benefits from loss of dead skin and parasites
Why is the pyramid of biomass a pyramid?
- Because it shows how energy is transferred from the food chain to the environment at each trophic level
- Helps to explain why there is a maximum length of food chain in an ecosystem
How do some species of lichen act as air pollution indicators?
- They grow on trees and buildings and have a mutualistic relationship between fungus + alga
- For the last 20 yrs only found in industrial areas
- They are only lichen to tolerate air pollution with sulfur-containing gases from burning fossil fuels
How are blackspots on rose leaves indicators of air pollution?
- It is a fungus and pathogen of roses
- Cannot grow where there is a lot of sulfur pollution
- Roses growing in cities rarely suffer from blackspot infection
What can water pollution be caused by?
Poisonous substances released by factories such as mercury or detergents, or fertilisers and sewage
What does eutrophication encourage?
The rapid growth of algae and plants
What is negative about algae and plants growing in the water due to eutrophication?
They reduce the O2 concentration in the water, killing many animals living in it
How can you calculate the efficiency of energy transfer?
ENERGY TRANSFERRED TO BIOMASS/TOTAL ENERGY SUPPLIED TO ORGANISM X 100
How are stonefly larvae water pollution indicators?
Can only live in water that contains lots of O2, so show unpolluted water
How are bloodworms indicators of water pollution?
Can live in water that contains little oxygen, so are found in polluted water
How much energy from the Sun to the Earth is lost by reflection or used to evaporate water/heat up the soil?
About 98%, so only 2% gets trapped by the producer
Where is energy lost at each trophic level?
By heating, urine, faeces and respiration
Describe how to carry out random sampling using a quadrat
- Place x and y axis along floor using measuring tape
- Random number generator for coordinates
- Place quadrat at corner of coordinate (1m^2)
- Count biotic factor in quadrat
- Repeat 10 times at different random coordinates for accuracy
- Calculate mean value
- Find out area of whole space
- TOTAL AREA (M^2)/AREA OF ONE QUADRAT (M^2) X MEAN NUMBER OF ORGANISMS IN ONE QUADRAT
Describe how to carry out sampling using a belt transect
- Place a piece of rope/tape measure across the habitat you are looking at
- Use a quadrat to count the number of organisms at intervals (e.g. every 1/2m) on the transect to see how the number of organisms change along the line
- Repeat this 3 times by moving the line across the habitat and repeat the whole process for validation
How is fish farming beneficial?
As human population increases, fish intake increases and people overfish; fish farming aims to produce more fish and so reduce overfishing of wild fish
How does fish farming cause problems?
- Many fish are kept in a relatively small space and so are cramped and parasites/disease spread more easily between fish so need to be treated frequently to keep them healthy
- Uneaten food and faeces from the fish sink to the bottom of the water which can change conditions and may harm the fish living there
What are indigenous/native species?
Organisms that have always been in an ecosystem
Why are some non-indigenous species sometimes introduced to areas?
To reduce the number of another species that has got out of control
What is eutrophication?
The addition of more nutrients to an ecosystem than it normally has
Describe how eutrophication can affect an aquatic ecosystem
- Fertiliser added
- Heavy rain washes fertiliser off
- Nitrates and phosphates dissolve in soil water
- Nitrates and phosphates not taken up by plants are washed into stream or river
- High nitrate and phosphate concentrations in the water encourages plants and algae to grow rapidly
- Surface plants block sunlight, so plants in the water die and stop producing oxygen through photosynthesis
- Bacteria that break down dead materials increase in numbers and use up more oxygen from the water
- Oxygen concentration of water decreases
- Aquatic animals like fish die due to lack of oxygen
What is fish farming?
Growing one kind of fish in an area
What are pooters used for?
To suck small insects from vegetation without harming them
What can nets be used for when estimating insect population sizes?
Can be swept through grass, bushes, streams or ponds (small insects are collected)
Describe a pit-fall trap
- Walking/crawling insects from the soil surface or leaf little can be attracted to a jar with jam or meat inside
- Make a soil slope around the jar
- Wood/stone cover so birds/predators don’t eat them
- Small stones to raise it to allow insects to get in
Describe a tullgren funnel
-Heat source above funnel and beaker with alcohol at bottom
Funnel with soil and leaf litter on top of beaker with metal gauze-
Small insects and other arthropods move done away from the heat source towards the cooler moist conditions
What is the moral reason for maintaining biodiversity?
Humans should respect other living organisms
What is the aesthetic reason for maintaining biodiversity?
People enjoy seeing the variety of living organisms that live in different habitats?
Why is ecosystem structure a reason for maintaining biodiversity?
Some organisms maintain an important role in ecosystems as microorganisms in decay processes and nutrient recycling. If we lose species, food chains become more unstable
Why is usefulness a reason for maintaining biodiversity?
Some species are particularly useful to humans, like plants that produce life-saving drugs or wild varieties of plants grown for crops as a source of genes if the environment changes
What is reforestation?
Replanting forests where they have been destroyed, like to create farmland
What are the advantages of reforestation?
- Restores habitats for endangered species
- Reduces the concentration of carbon dioxide in the air as the trees photosynthesise
- Tree roots bind the soil together and reduce the effects of soil erosion
- Affects local climate, such as reducing temperature variation
What is food security?
Having access to enough safe and healthy food at all times
What do healthier countries prefer to eat?
Meat and fish
What do some think we should eat to help protect the environment?
More vegetable protein as opposed to meat and fish protein
Why is growing food from crops using agricultural inputs (fertilisers) an issue?
- Most of the fertiliser is made using chemical processes that need energy and release CO2, raising concerns about sustainability
- Increase eutrophication
How does growing plants for biofuels reduce carbon emissions?
The carbon released by burning a biofuel is only the amount removed from the air by the crop as it grew and so does not contribute to rising levels of carbon emissions
What is wrong with biofuels?
Land that could have been used to grow crops was used to grow biofuels
What are the soft tissues of organisms decayed by soon after death?
Decomposers
Where do decomposers grow best?
In moist and warm conditions, and many of them need oxygen
What do most methods of food preservation rely on?
- Reducing temperatures (freezers)
- Reducing water content (salting and drying)
- Irradiation of packaged foods (to kill decomposers)
- Reducing oxygen (storing foods in oil)
What are foods that easily decay often packaged in?
An unreactive gas like nitrogen
What forms compost?
Waste garden material in heaps that have been well-decayed
What does the decay process allow for composts?
To be absorbed easier by plants
What does compost increase?
Soil fertility
How do you calculate rate of decomposition?
MASS LOST (G)/NUMBER OF DAYS
What is decay?
The break down/digestion of materials by microorganisms
How does salting foods work?
It causes water to move out of bacterial cells by osmosis so there is not enough water in the microorganism cells for them to grow
What do ions form when they decompose?
Ammonia
Why do we need nitrogen?
Contains amino acids that help make proteins in our bodies
What is bioaccumulation?
Heavy metals or chemicals that stay in your fat
How does vinegar help in food preservation?
It is an acid and so lowers the pH so enzymes of microbes cannot work
What do compost activators contain?
Bacteria and fungal spores
What is crop rotation?
Taking turns growing/harvesting different crops each year on the same land that take different quantities of mineral ions out of the soil
Describe an example of crop rotation
- Wheat has a high demand for nitrate ions
- Potatoes has a low demand of nitrate ions
What percentage of our atmosphere is nitrogen?`
78%
What does nitrogen-fixing bacteria do?
They convert nitrogen to nitrates
What does denitrifying bacteria do?
Converts nitrates back into nitrogen
What is waterlogged soil?
All internal spaces are concentrated with water (no air)
How can you treat waterlogged soil?
Use a drainage system to unclog using pipes
What does nitrifying bacteria do?
Converts ammonia into nitrates
What is aerboic bacteria?
Bacteria that needs oxygen
How does the nitrogen cycle?
- Decomposers break down dead plants and animals and their waste products
- Soil bacteria convert proteins and urea into ammonia
- Nitrifying bacteria convert ammonia into nitrates
- Plants absorb them from the soil and use it to make their proteins which are essential for growth
- Plants eaten by herbivores and so the nitrogen gets passed along the food chain/web
- Denitrifying bacteria live in waterlogged soils and convert nitrates back into nitrogen gas (menace to farmer)
- Farmer may grow legumes to improve nitrogen content of soil or nitrogen fertiliser
- Lightning can provide energy to convert nitrogen gas into nitrates
How does growing legumes in a crop rotation improve the nitrogen content of soil?
These plants have swellings in their roots called nodules which contain nitrogen fixing bacteria which can convert nitrogen gas directly into nitrates
Why is it best not to apply nitrogen fertiliser before it rains or too much?
It may cause eutrophication by spilling into the nearest river/stream
What process makes synthetic fertiliser?
Haber Process
Describe the substance trade between the roots of a legume and the leaves
- Rhizobium (nodules) at end of plant root absorb nitrates and give to rest of plant
- Leaves that capture glucose transfer to rhizobium
What % of our bodies are composed of nitrogen compounds?
3%
What is manure?
Animal waste used as fertiliser
What does manure do?
Makes use of the decay process as fertiliser
Why is the carbon cycle important?
carbon makes up the foundation of all organic material
How much CO2 is in our air?
0.035%
What is decomposition?
Respiration carried out by bacteria
Describe the carbon cycle
- Carbon taken from the atmosphere by plants by photosynthesis
- Passed on to animals and decomposers by feeding
- Returned to the air by respiration, burning fossil fuels and decomposition by microorganisms
Is the water cycle an open or closed ciycle?
Closed
Is there an energy input for the water cycle?
None apart from for evaporation
Describe the water cycle
- Water evaporates from oceans, lakes and rivers as water vapour
- As air rises, it cools and condenses to form clouds
- As water droplets get too large and heavy they fall as rain/snow
- Groundwater moves through soil and rock to nearby rivers
- Rivers flow into lakes and eventually returns to the ocean
What is the cell cytoplasm mostly made of?
Water
What is potable water?
Safe for drinking
In places of drought, how can water be collected?
Catching droplets of water or misty air with collection pipes and cold nets for condensation
What is desalination?
Obtaining fresh water from the sea/salty water
