AQA - Ecology

What is an ecosystem?

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

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 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 ans suitable pH

What can decomposers be used for?

Compost heaps

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

It reduces the amount of land available for animals

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 by?

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 is a pyramid of biomass used to show?

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