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