Biology - ECOLOGY (B7)

Ecosystems & Interdependence -

What is an ecosystem?

A community of organisms interacting w/ the biotic + abiotic elements of their environment.

Ecosystems & Interdependence -

Define “community” in ecological terms.

All the populations of different species living + interacting in a habitat.

Ecosystems & Interdependence -

What is interdependence?

The way in which species rely on each other for food, shelter, pollination, etc.

Ecosystems & Interdependence -

What is a stable community?

One where the population sizes remain relatively constant due to balanced biotic + abiotic factors.

Abiotic & Biotic Factors -

What are abiotic factors? Give 3 examples.

Non-living factors:

Light intensity

Temperature

Water availability

Abiotic & Biotic Factors -

What are biotic factors? Give 3 examples.

Living factors:

New predators

Competition

New pathogens

Abiotic & Biotic Factors -

How can a change in abiotic factors affect a community?

Can reduce population sizes by affecting growth or reproduction.

Abiotic & Biotic Factors -

How can biotic factors cause changes in population size?

Changes in predation, disease / competition can increase / decrease populations.

Adaptations -

What is an adaptation?

A feature that helps an organism survive + reproduce in its environment.

Adaptations -

What are the three types of adaptations?

Structural (e.g. thick fur)

Behavioural (e.g. migration)

Functional (e.g. concentrated urine)

Adaptations -

What is an extremophile?

An organism that can live in extreme environments, such as high temperature, salinity, / pressure.

Organisation of an Ecosystem -

What is a producer?

An organism (usually a green plant / algae) that produces its own food via photosynthesis.

Organisation of an Ecosystem -

What is a primary consumer?

An organism that eats producers - usually a herbivore.

Organisation of an Ecosystem -

What is a trophic level?

The position of an organism in a food chain.

Organisation of an Ecosystem -

What is the role of decomposers?

Break down dead organisms + waste materials to recycle nutrients.

Organisation of an Ecosystem -

How do decomposers break down materials?

They secret enzymes to digest materials externally + absorb the nutrients.

Pyramids of Biomass & Energy Transfer -

What does a pyramid of biomass show?

The relative mass of living material at each trophic level.

Pyramids of Biomass & Energy Transfer -

Why is energy transfer between trophic levels inefficient?

Only about 10% of energy is transferred; most is lost via respiration, movement, / as heat.

Pyramids of Biomass & Energy Transfer -

How can biomass be lost in a food chain?

Through:

Not all material being eaten

Waste

Movement + respiration

The Carbon Cycle -

What are the main processes in the carbon cycle?

Photosynthesis (removes CO2)

Respiration (releases CO2)

Combustion (releases CO2)

Decomposition (releases CO2)

The Carbon Cycle -

Why is the carbon cycle important?

It recycles carbon, a vital element in all living organisms.

The Water Cycle -

Name the key stages of the water cycle.

Evaporation

Condensation

Precipitation

Transpiration

The Water Cycle -

What is transpiration?

Loss of water vapour from plants via stomata.

Decay & the Cycle of Materials -

What factors affect the rate of decay?

Temperature

Oxygen availability

Moisture levels

Number of microorganisms

Decay & the Cycle of Materials -

What is compost?

Decayed organic matter used as a natural fertiliser.

Decay & the Cycle of Materials -

What is biogas + how is it produced?

A fuel produced by anaeorbic decay of biological material.

Environmental Change & Biodiversity -

What is biodiversity?

The variety of different species of organisms on Earth / w/in an ecosystem.

Environmental Change & Biodiversity -

Why is biodiversity important?

It ensures the stability of ecosystems by reducing dependence on one species.

Environmental Change & Biodiversity -

How do human activities reduce biodiversity?

Deforestation

Pollution

Overexploitation

Climate change

Environmental Change & Biodiversity -

What measures are being taken to protect biodiversity?

Breeding programmes

Habitat protection

Reduction of deforestation + waste

Recycling programmes

Pollution -

What are the main types of pollution?

Water pollution

Air pollution

Land pollution

Pollution -

How does pollution affect ecosystems?

It kills plants + animals, disrupts food chains, + reduces biodiversity.

Global Environmental Issues -

What causes global warming?

Increased greenhouse gases (CO2 + methane) trap heat in the atmosphere.

Global Environmental Issues -

What are the effects of global warming?

Rising sea levels

Habitat loss

Changes in migration patterns

Reduced biodiversity

Global Environmental Issues -

What is deforestation + why is it done?

Removal of forests for:

Farming

Timber

Biofuel production

Global Environmental Issues -

What are the environmental consequences of deforestation?

Less CO2 absorbed

More CO2 released

Reduced biodiversity