3.1.2: The Living World

Question 1

What is an ecosystem?

Answer 1

A set of living organisms that interact with each other and the environment around them. They are also dependent on the climate, soil and water.

Question 2

What is an example of a small-scale ecosystem in the UK?

Answer 2

Freshwater ponds:

• Pond bottom - Little oxygen/light, decomposers live here that eat dead material like water worms.
• Mid water - Fish live here that find food on the pond bottom or surface. Animals here breathe through gills or skin.
• Pond surface - Animals here breathe through gills, skin or lungs. Plenty of oxygen and light.
• Above pond - Birds like kingfishers and dragonflies live here.

Question 3

How is the food chain in the small-scale ecosystem structured?

Answer 3

Leaves/Algae -> Pond Bottom -> Mid Water -> Pond Surface -> Above Pond

Question 4

What are some examples of human/natural impacts on ecosystems?

Answer 4

Human:

• Introducing more fish
• Changing water levels
• Changing pH levels of water
• Changing nutrient levels in water via fertilisers.

Natural:

• Drought
• Flood
• Fire
• Disease

Changing any of these factors can massively impact an ecosystem and cause a food chain collapse.

Question 5

How are ecosystems distributed globally?

Answer 5

Taiga, forest and grassland covering most of Europe, Asia and North America.

Tropical rainforest, savannah and desert covering between tropics.

Hardwood forests covering south of Europe, north of Africa and south of Australia.

Tundra covering north-most and south-most areas of globe, e.g. Iceland, Greenland, south of Africa.

Question 6

What is the climate like in a tropical rainforest?

Answer 6

Extremely hot with over 28 degree temperature, very wet at over 2000mm rainfall a year, extremely humid atmosphere, with no seasons.

Question 7

What is the soil like in a tropical rainforest?

Answer 7

Infertile, with a thin layer of fertile soil at the surface where dead leaves decompose. Red in colour due to richness of iron. Nutrients washed out quickly by rainfall.

Question 8

Why is there lots of biodiversity in the tropical rainforest?

Answer 8

• Warm and wet climate is perfect for plant growth.
• Wide range of plant species supports wide range of animal species.
• Species have adapted to rainforest featers, e.g. trees with shallow roots to absorb nutrients from thin fertile soil.

Question 9

How is the rainforest structured?

Answer 9

• Ground layer - low light levels.
• Shrub layer - low light levels.
• Under canopy - medium light levels.
• Main canopy - reasonable light levels.
• Emergents - high light levels.

Question 10

How have plants adapted to the rainforest?

Answer 10

Lianas - tall woody vines that have roots in the ground but climb trees to reach the sun. Their leaves and flowers grow in the canopy.

Drip tips - leaves with pointy ends, to allow water to run off without damaging the leaf.

Buttress roots - large roots that have ridges to create a large surface area, supporting the tree in the shallow soil.

Epiphytes - plants that live on the branches of trees in the canopy, that get nutrients from the air and water.

Question 11

How have animals adapted to the rainforest?

Answer 11

Sloth - moves slowly and uses camouflage to make it difficult for predators to spot.

Spider monkey - long, strong limbs to help climb through forest.

Flying frog - Webbed hands and feet with loose skin between limbs to allow for gliding.

Toucan - long bill to allow it to reach fruit on weak branches.

Question 12

Why are humans deforesting, using a case study?

Answer 12

Case Study: Amazon Basin

• Farming - large areas cleared to farm cattle and cash crops, to keep up with increasing demand.
• Logging - logs can be sold as timber for profit.
• Mining - Basin is rich in iron, tin, and aluminium. Mines have developed to exploit this, which require clearing to create.
• Roads - access is needed for farmers and loggers, leading to destruction of large areas.
• Hydroelectric Power - large areas flooded to create reservoirs and dams - Balbina Dam in Brazil lead to 920 square miles of rainforest being lost.
• Population - population growth = more houses needed = expansion into rainforest.

Question 13

What are the impacts of deforestation?

Answer 13

• Soil erosion - no plants means no leaf litter, which means soil doesn’t recover from being picked up by plants, plants die, soil washed and blown away by water and wind.
• Loss of biodiversity - plants die, but animals dependent on said plants also die.
• Climate change - Rainforest acts as carbon sink, removing carbon sink = more carbon dioxide in atmosphere = climate change.
• Economic development - money gained from business in forest leads to development in country, e.g. improved infrastructure.

Question 14

How can tropical rainforests be managed to reduce deforestation, with a case study?

Answer 14

Case Study: Malaysia

• Only logging mature trees and replanting after logging means that canopy is never empty/destroyed - Selective Management System in Malaysia.
• Educating the locals on biodiversity and tourism so they learn to protect it.
• Promoting ecotourism (environmentally friendly tourism) to conserve the rainforest for future generations to come.
• Permanent Forest Estates where no change of land use is allowed set up by governments.