GCSE AQA Biology- Ecology

What is an ecosystem?

The relationship between all living and non-living parts of a habitat

What are the 3 levels of organisation in an ecosystem?

Individual organisms, populations, communities

What is a population in an ecosystem?

Groups of individuals of the same species

What is a community in an ecosystem?

Made of many populations living together

What is competition in an ecosystem?

Organisms competing for resources

What do plants compete for?

Light, water, minerals from soil and space

What do animals compete for?

Food, mates and territory

What is interdependence?

When species rely on each other for food, shelter, pollination, seed dispersal etc

Why would removing one species from an ecosystem be bad for an ecosystem?

Because of interdependence, it can affect the whole community

What happens in a stable community?

All species and environmental factors are in balance so that population size stays fairly constant.

What is an example of a stable community?

A rain forest or ancient oak woodland

What is an abiotic factor?

A non-living factor that effects the community

What is a biotic factor?

A living factor that effects a community

What do abiotic factors include?

Light intensity, temperature, moisture levels, soil pH and mineral content, wind intensity and direction, carbon dioxide levels (Plants), oxygen levels (Aquatic animals)

What do biotic factors include?

Availability of food, new predators arriving, new pathogens, one species out-competing another

What are adaptations?

Features that allow an organism to survive in the conditions that they normally live in

What is a structural adaptation?

A physical adaptation. Features an organism has such as fur, beaks etc

What is a behavioural adaptation?

Something an organism does to allow it to survive

What are functional adaptations?

An internal working or body process that allows an organism to survive

What are extremophiles?

Organisms that can live in extreme conditions such as high pressure, high salt concentration, or high temperatures

What is an example of an extremophile?

A tardigrade

What method can be used to study an ecosystem?

Transect line and a quadrat

What are decomposers?

Organisms that break down dead or waste material

What type of organisms are decomposers?

Fungi and bacteria

What do decomposers need?

Oxygen, moisture, a suitable temperature and suitable pH

How do decomposers break down the waste?

They secrete enzymes which partly digest the waste

What do decomposers do with the small molecules produced by their enzymes?

They take up the small, soluble molecules by diffusion

What can decomposers be used for?

Compost heaps

Why do gardeners stir their compost heaps?

Because oxygen is needed. In anaerobic conditions, methane gas is produced

What is the carbon cycle?

It describes how carbon is recycled in nature

Why does the carbon cycle depend on decomposers?

To return carbon to the atmosphere as carbon dioxide through respiration

What is the water cycle?

Describes how fresh water circulates between organisms, rivers and the sea.

What is a producer in a food chain?

It synthesises molecules

What is an example of a producer?

A green plant, which produces glucose molecules by photosynthesis

What are producers eaten by?

Primary consumers

What are consumers eaten by?

Secondary consumers

What are secondary consumers eaten by?

Tertiary consumers

What is each level of a food chain called?

A trophic level

What is a predator?

Consumers that eat other animals

What is prey?

The animals that are eaten by predators

What are apex predators?

Carnivores with no predators

What happens to the number of prey and predators in a stable community over time?

The numbers of each rise and fall in cycles

How can the balance of predators and prey be shown?

A predator-prey graph

What is biodiversity?

The variety of all different species on Earth or in an ecosystem

Why does a high biodiversity maintain a stable community?

Species depend on each other for food and shelter

What are the factors that are changing which threaten biodiversity?

Availability of water, temperature, atmospheric gases

Why are the factors affecting biodiversity changing?

Changes in the season, geographic activity (volcanoes, storms), human interaction

What is pollution doing?

Killing plants and animals

When or where can pollution occur?

In water from sewage, fertilisers or toxic chemicals, in air from gases, on land from landfill and toxic chemicals

What is overexploitation?

When humans take too many resources out of the environment

What is the effect of overexploitation and why?

It reduces biodiversity because not enough nutrients are left for other animals and plants

What is the effect of building, quarrying, farming and dumping waste?

It reduces the amount of land available for animals

Why does producing compost reduce biodiversity?

It destroys peat bogs, reducing habitat of the organisms living there

What does the burning and decay of peat lead to?

The release of carbon dioxide

Why has deforestation occurred in tropical areas?

To provide land for cattle and rice fields , to grow crops which biofuel can be produced from

What is global warming?

The gradual increase in the temperature of the Earth

What do scientists think the causes of global warming are?

The changes in gases in the atmosphere

What are the changes of gases in the atmosphere caused b?

Pollution and deforestation

What are the gases that cause global warming?

Methane and carbon dioxide

What are the biological consequences of global warming?

Loss of habitat when low lying areas are flooded by rising sea levels, changes in the distribution of species when an areas temperature or rainfall has changed, changes in the migration patterns of animals

What are the steps scientists and governments have taken to conserve biodiversity?

Setting up breeding programs, protecting rare habitats, encouraging farmers to keep margins and hedgerows in fields, reducing carbon emissions, reducing the rate of deforestation, recycling resources

What is food security?

Ensuring the world's population is supplied with enough food to be healthy

What are the factors that are making it harder to supply the world's population with food?

Increasing birth rate, changing diets in developed countries, new pests and pathogens affecting farming, changes in weather, cost of agricultural supplies

What is a pyramid of biomass used to show?

The amount of biomass in each trophic level of a food chain.

Why do losses of biomass occur?

Some of the food taken in is lost as faeces, large amounts of glucose are used in photosynthesis, some material is lost in excretion

Why does a loss of biomass help to shape the pyramid of biomass?

The loss of biomass and reduction in energy means there are fewer organisms in the higher trophic levels

How can the efficiency of food production be increased?

By reducing the energy transfer from animals to the environment by limited the movement of animals and controlling the temperature of their surroundings

How does factory farming enforce the things you can do to increases food production?

Raising chickens in cages, calves in pens and giving them high protein foods to increase growth

What are the regulations to stop fish numbers decreasing?

Control the size of nets to ensure only adult fish are caught, set fishing quotas

What does biotechnology allow?

It allows microorganisms to be grown in large quantities for food

What are microorganisms for biotechnology grown in?

Fermenters

What is the fungus used to make mycoprotein?

Fusarium

What is mycoprotein used to make?

Quorn

What are the properties of mycoprotein?

Protein rich, low in fat, high in fibre, suitable for vegetarians

How is fusarium used in mycoprotien grown in a fermenter?

On a glucose syrup, in aerobic conditions, then is harvested and purified

What can GM crops be used for in food production?

To provide more food or food with and improved nutritional value