ecosystems and material cycles

What is an individual?

A single organism

What is a population?

All the organisms of one species in a habitat

What is a community?

All the organisms of different species living in a habitat

What is an ecosystem?

A community of organisms along with all the abiotic conditions

What are abiotic factors?

Non-living factors

What are biotic factors?

Living factors

How does temperature affect communities?

Change in average temperature can affect distribution of some organisms

How does light affect communities?

Different plants may grow in a more shaded area

How does water affect communities?

Different plants will die if soil is too dry or waterlogged

How do pollutants affect communities?

Can poison or harm organisms

How does competition affect communities?

Organisms compete with other species for the same resources

How does predation affect communities?

If there are less predators, there will be more prey

What is interdependence?

When organisms depend on each other for food or shelter to survive and reproduce

What does interdependence mean for a community?

A change in the population of one species can have huge knock on effect for other species in the same community

What is mutualism?

Where both organisms benefit in a relationship

What is parasitism? 

Parasite benefits by feeding off a host organism often causing harm to it

What is the first step in using a quadrat to study organisms?

Place a (1 \text{ m}^2) quadrat on the ground at a random point within first sample area

How can you find a random point to place the quadrat when studying organisms?

Divide sample area into grid and use random number generator to pick coordinates

Why is it important to place the quadrat randomly when studying organisms?

To ensure results are representative of whole sample area

What do you do after placing the quadrat when studying organisms?

Count all organisms you're interested in within the quadrat

What do you do after counting organisms in the quadrat when studying organisms?

Repeat placing the quadrat and counting organims many times

What do you do after repeating counting the organisms when studying organisms?

Work out mean number of organisms per quadrat within first sample area

How do you calculate the mean number of organisms per quadrat?

[\frac{ \text{Total number of organisms} }{ \text{Number of quadrats} }]

What do you do after calculating mean number of organisms per quadrat in studying organisms?

Repeat sampling and counting then calculate the mean for the second sample area

What do you do after calculating the mean number of organisms for the second sample area when studying organisms?

Compare the means of the two sample areas

What is a change in abiotic factors across a habitat called?

Gradient

How is the distribution of organisms along a gradient studied?

Belt transect

What is the first step in using a belt transect?

Mark out a line in area being studied

What do you do after marking a line when using a belt transect?

Collect data along the line using quadrats placed next to each other

What can you do to collect data when the belt transect is long?

Place quadrats at regular intervals instead of next to each other

How do you collect data using a quadrat in a belt transect? (Count)

Count all organisms of species being studied

How do you collect data using a quadrat in a belt transect? (Estimate)

Estimate percentage area of a quadrat covered by a certain organism

What additional data could you record in a belt transect?

Mean height of plants or abiotic factors in each quadrat

What do you do after collecting data in a belt transect?

Repeat marking a line and collecting data several times

What do you do after repeating collecting data in a belt transect?

Find the mean number of organisms or mean percentage cover for each quadrat

What do you do after finding mean number/percentage cover of organisms in a belt transect?

Plot graphs to see if changing the abiotic factor affects distribution of species being studied

How do you calculate the mean number of organisms in a given area?

[\text{Mean number of organisms per } m^2 \times \text{Total area of habitat in } m^2]

How is some energy transferred to less useful forms at each trophic level?

Used to keep organism alive like in respiration which transfers heat energy to surroundings

Why is energy that an organism uses to keep itself alive not transferred to next trophic level?

Not stored as biomass and usually dissipated to surroundings 

Why does energy that does get stored as biomass not all get transferred to next trophic level? (Eating)

Not all parts of an organism are eaten such as bones

Why does energy that gets stored as biomass not all get transferred to next trophic level? (Digestion)

Not all parts of an organism that are eaten can be digested

What happens to undigested material in a food chain?

Lost in faeces

Why are there hardly ever food chains with more than five trophic levels?

Too much energy is lost at each trophic level so there is not enough to support organisms after five

Why do there tend to be less organisms at each trophic level?

Not enough energy to sustain higher trophic levels

What does a pyramid of biomass show? (Mass)

Total mass of all organisms in a food chain

What does a pyramid of biomass show? (Energy)

Amount of energy in each trophic level

Why does the mass of organisms go down each trophic level in a pyramid of biomass?

Most biomass is lost and does not become biomass in next level up

How do you calculate the efficiency of energy transfers between trophic levels?

[\frac{ \text{Energy transferred to next level} }{ \text{Energy available at previous level} }]

What is biodiversity?

Variety of living organisms in an ecosystem

What happens if too much fertiliser is applied and it rains afterwards?

Nitrates run off into rivers and lakes causing eutrophication

What is eutrophication?

An excess of nutrients in a body of water

What can eutrophication lead to?

Death of many species present in water which reduces biodiversity of the habitat

What is the first step of eutrophication?

Fertilisers cause excess nitrates to enter water

What happens after excess nitrates enter water in eutrophication?

Cause algae to grow quickly and block out light

What happens after algae blocks light in eutrophication?

Plants can't photosynthesise due to lack of light so start to die and decompose

What happens after plants decompose in eutrophication?

Microorganisms that feed on decomposing plants increase in number as more food is available

What do the increased number of microorganisms in eutrophication do?

Use up all oxygen in water

What happens when microorganisms use up all oxygen in water in eutrophication?

Organisms that need oxygen for aerobic respiration like fish die

What is the first step of fish farming reducing biodiversity?

Food is added to nets to feed the fish which produce a lot of waste

What can happen to the food and fish waste in fish farming?

Can leak into open water and cause eutrophication or death of wild species

What do fish farms in open water often act as?

Breeding ground for large numbers of parasites

What could happen to parasites in fish farms?

Can leak out of farm and infect or kill wild species

How can fish farms be dangerous to predators like sea lions?

Can become trapped in nets and die

What can sometimes happen in fish farms?

Farmed fish can escape into wild, causing problems for wild populations of indigenous species

Why are fish farmed in large tanks low in biodiversity?

Only one species is farmed with tanks free of any plants, predators, and parasites

What is a non-indigenous species?

Species that doesn't naturally occur in an area

How can non-indigenous species be introduced?

Intentionally or unintentionally

What can non-indigenous species do to reduce biodiversity? (Compete)

Compete with indigenous species for resources like food or shelter

What is a result of non-indigenous species out-competing indigenous ones?

Indigenous decrease in number and eventually die out

What can non-indigenous species do to reduce biodiversity? (Disease)

Bring new diseases to a habitat

What is a result of non-indigenous species bringing new disease?

Can infect and kill indigenous species which reduces habitat's biodiversity

What is reforestation?

Replanting a forest in land where there used to be one

Why do forests generally have a high biodiversity?

Contain a wide variety of trees and plants which animals use for food and shelter

What does reforestation do?

Increases biodiversity of deforested areas

What is an example of maximising positive effects of reforestation?

Replanting a variety of tree species will result in a higher biodiversity than one type

What do conservations schemes do?

Help to protect biodiversity by preventing species from dying out

What is an example of a conservation method? (Habitat)

Protecting a species' natural habitat

What is an example of a conservation method? (Captivity)

Protecting species in safe areas outside their natural habitat

What can be done in species kept in captivity for safety to increase numbers?

Introducing captive breeding programmes

What is an example of a conservation method? (Seeds)

Using seed banks to store and distribute seeds of rare or endangered plants

What are the benefits of maintaining biodiversity? (Food)

Protects the human food supply as conservation programmes reduce effects of over-fishing

What are the benefits of maintaining biodiversity? (Food chains)

Ensures minimal damage to food chains which helps other species by conserving one

What are the benefits of maintaining biodiversity? (Medicine)

Provides future medicines as many medicines come from plants

What are the benefits of maintaining biodiversity? (Culture)

Cultural aspects are important like a national animal of a country

What are the benefits of maintaining biodiversity? (Ecotourism)

People are drawn to visit unspoilt landscapes with a variety of animal and plant species

What is an impact of ecotourism?

Helps bring money into biodiverse areas where conservation projects are happening

What are the benefits of maintaining biodiversity? (Jobs)

Provides jobs for local people in ecotourism, conservation or reforestation schemes

What is food security?

When everyone has access to enough food that is safe to eat and has correct balance of nutrition

How does the increasing human population affect food security?

More food must be produced so each person still has same amount of food to eat

What affects people's preference for meat and fish?

More wealthier are more likely to include more meat and fish in diets

Why does increasing consumption of meat and fish affect food security?

Less energy and biomass at each trophic level in a food chain

What does less energy and biomass in each trophic level mean for animal farming in food security?

More food can be produced in same land by farming crops instead of animals

How does increased animal farming affect food security?

Animals and fish reared to be eaten are often fed crops otherwise eaten by humans

How does increased fish consumption affect food security?

Risk of over-fishing wild fish so there may not be enough to catch in the future

How do environmental changes due to human activity affect food security?

Burning fossil fuels releases greenhouse gases which cause global warming

How does global warming affect food security?

Can cause other forms of climate change which can affect growth and yield of crops

How can other environmental changes caused by humans like soil pollution affect food security?

Can reduce ability to grow crops

What is a sustainability issue in food security? (Biofuels)

Land to grow biofuels can be used to grow food crops instead

What must be done to maintain food security in land used for biofuels?

Balance the need for land to make biofuels and with need to make food

What is a sustainability issue in food security? (Costs)

High input costs of farming can make it too expensive for farmers in some areas to maintain food production in future