Biodiversity is the range of different living organisms that live in a place.

Fertiliser are minerals that are added to the soil to help plants to grow.

Eutrophication is the process in which a body of water is overly enriched with plant nutrients. This leads to excessive growth of simple plants such as algae.

Indigenous species are a species that occurs naturally in an ecosystem. They are sometimes referred to as native species.

Examples of human interactions with ecosystems, including fish farming

Biology

Transfers of biomass between trophic levels

Negative human interactions with ecosystems and impacts on biodiversity

Benefits and challenges of maintaining biodiversity

Climate change and biodiversity: changes in the distribution of organisms

Factors affecting human food security, and possible solutions

Pupils learned about biotic and abiotic components of an ecosystem, measuring population size, interdependence and competition in ecosystems, how changes in biotic and abiotic factors affect communities, the cycling of carbon and water, and the role of microorganisms in cycling materials through ecosystems.

This unit explores trophic levels, biomass pyramids, and the efficiency of biomass transfers in ecosystems. It examines human impacts on biodiversity, factors affecting food security, and biotechnological solutions. Emphasis is on evaluating environmental changes and ethical considerations.

Maintaining biodiversity and human impacts

Fishing that does not reduce the population size of fish species

Fishing that does not reduce the plant species in a habitat

Fishing that causes a significant reduction in fish population sizes.

Fishing that only catches large fish due to large net sizes.

They have no natural predators in the area.

They are eaten by many animals in the area.

Why do the populations of invasive species often grow so quickly? 

Algae and other plants use up all the carbon dioxide.

Fish grow quickly due to all the plant food available.

Algae grows on the surface and blocks out all of the light.

The water becomes less polluted as it is cleaned by the plants.

What happens when eutrophication in a pond takes place?

Food security (the amount of food) for humans will improve.

Populations of fish are at risk of extinction.

Other organisms in food chains are affected.

Which of the following is NOT a consequence of declining fish populations?

Non-native plants are able to adapt quickly.

Non-native plants cause native animals to move to other habitats.

Non-native plants compete with native plants for resources.

Non-native plants are eaten more by native animals.

When taken to a new habitat, non-native plants often threaten native plants of the new habitat.  Why do they do this?

Fertiliser from farming is washed into rivers and ponds.

Introduction of new species from other parts of the world.

How do humans cause eutrophication of aquatic habitats?

What does an increase in atmospheric carbon dioxide cause?

Which of the following reduces the land available for other organisms and therefore reduces biodiversity?

Less trees give out large amounts of carbon dioxide

Less trees take in less carbon dioxide to photosynthesise

Crops grown on deforested land take in more carbon dioxide

Why does deforestation increase the amount of carbon dioxide in the atmosphere?

Migration patterns are being disrupted as the seasons change.

Animals are migrating in the same way as they always have.

Almost all species now have to migrate as the climate changes.

Some species migrate. What impact does global warming have on these species?

Methane is one of the greenhouse gases. What human activities are leading to a rise in atmospheric methane levels?

A long term shift in weather patterns is known as...

Starter Quiz

What does an increase in atmospheric carbon dioxide cause?