Human impact on ecosystems

What are the three main types of pollution?

• Air → smoke, sulfur dioxide (acid rain).

• Water → sewage, fertilisers (causing eutrophication).

• Land → toxic chemicals, landfill, pesticides.

How does pollution reduce biodiversity?

It destroys habitats, kills species, and disrupts food webs.

How do humans use land in ways that affect ecosystems?

For building, farming, quarrying, and dumping waste.

How does deforestation affect ecosystems?

• Loss of habitats and biodiversity.

• Reduced carbon dioxide absorption.

• Increased risk of climate change.

What causes global warming?

Increased greenhouse gases (CO₂ from burning fossil fuels, methane from cattle farming and landfill).

What are consequences of global warming?

Rising sea levels, habitat loss, changing migration patterns, reduced biodiversity, possible extinction.

Why is biodiversity important?

Provides food, medicine, materials, and ensures stable ecosystems.

What methods can help maintain biodiversity?

Breeding programmes, protecting habitats, recycling resources, laws against poaching, reducing deforestation/pollution.

What is food security?

Having reliable access to enough safe and nutritious food.

What factors threaten food security?

Increasing population, climate change, overfishing, pests/diseases, high farming

costs.

How can farming be made more efficient?

• Reducing energy transfer by limiting animal movement.

• Controlling temperature in barns.

• Using high-yield GM crops.

What are the disadvantages of intensive farming?

Ethical concerns (animal welfare), risk of disease spread, reliance on chemicals.

What is mycoprotein and how is it made?

A protein-rich food made from the fungus Fusarium, grown in aerobic conditions on glucose syrup.

How is genetic engineering used in food production?

GM crops → increased yield, pest resistance, enhanced nutrition.

How is biotechnology used in medicine?

Genetically engineered bacteria produce insulin and other medicines.

What factors affect the rate of decay?

Temperature, moisture, oxygen availability, and number of decomposers.

How is biogas made?

Microorganisms break down biomass anaerobically, producing methane, which can be burned as fuel.