AQA GCSE Geography - The Living World (copy)

Starred terms for EOY

What does a producer do?

- a producer uses sunlight energy to produce food

What is the nutrient cycle?

1) plants drop leaves => dead material decomposes => nutrients are released into the soil

2) nutrients are then absorbed from the soil by plants => those plants may then be eaten by consumers

3) plant/consumer who ate the plant dies => nutrients returned to the soil

4) transfer of nutrients = nutrient cycling

What are the features of a hot desert ecosystem?

- found between 15° and 35° N/S of the equator
- little rainfall
- very hot during the day
- very cold at night
- shrubs and cacti are sparsely disttributed in the sandy soil

What are the features of a tropical rainforest ecosystem?

- found around the equator, between the tropics (hot and wet all year around)
- dense canopies of vegetation forming distinct layers

What is the climate like in tropical rainforests?

- same all year round
- hot (sun's energy is more intense near the equator as it is overhead all year around)
- very high rainfall

What are the plants like in tropical rainforests?

- most trees are evergreen = trees are very tall
- dense vegetation cover
- lots of epiphytes (plants that grow on other living plants and take nutrients and moisture from the air), e.g. orchids and ferns

Why isn't the soil very fertile in tropical rainforests?

- heavy rain washes nutrients away
- only thin layer of surface nutrients due to decayed leaf fall (decay is fast in the warm, moist conditions)

What are the inhabitants (natives) like in tropical rainforests?

- many indigenous people have adapted to life in the rainforests
- they hunt, fish, and gather nuts and berries for food
- also grow vegetables in small garden plots (subsistence or commercial farming)

What is biodiversity?

- the variety of organisms living in a particular area (plants & animals)
- rainforests have an extremely high biodiversity

Why are rainforests stable and productive?

- their climate is always hot and wet

Why is the biodiversity in tropical rainforests decreasing?

- deforestation and uncontrolled development are likely to lead to the extinction of many species => loss of biodiversity

What effect can deforestation have on a tropical rainforest?

- cutting down trees => can contribute to climate change

- trees intercept & take up lots of water & release it back into the atmosphere => providing moisture for further rainfall (reducing tree cover may increase the risk of drought, affecting the animals/plants)

- trees stabilise soil with their roots and provide some nutrients when they drop their leaves
- fewer trees => soil would have less protection from heavy rainfall => even fewer nutrients in the soil as they are washed away more easily

To what 3 things are plants adapted to in tropical rainforests?

- high rainfall
- high temperatures
- competition for light

What are the 4 layers of plants with different adaptations?

1) Emergent trees
2) Main canopy
3) Undercanopy
4) Shrub layer

How do trees compete for sunlight?

- trees compete with each other for sunlight by growing tall

How are the leaves of plants adapted for the heavy rainfall?

- thick, wavy leaves with pointed drip-tips => channel rainwater to the point, encouraging runoff (weight of the water doesn't damage the plant + no standing water for bacteria/fungi to grow)

How are lianas adapted to compete for sunlight?

- lianas use tree trunks to climb up high to reach sunlight

How are trees adapted to the heavy rainfall?

- smooth, thin bark => water runs off easily

What feature do trees have which supports their tall, tree trunks?

- large, stable buttress roots

How are some undercanopy plants adapted to receive the most sunlight?

- large leaves to absorb as much sunlight as possible

How are howler monkeys adapted to keep away from predators?

- howler monkeys have strong limbs so they can move around quickly and easily high up in the canopy

Why do harpy eagles have short, pointed wings?

- so that they can easily manoevre between the dense tangle of trees

How are flying squirrels adapted to escape predators?

- flaps of skin between body and arms that allows them to glide between trees

How are leaf-tailed geckos adapted to escape predators?

- camouflaged to look like leaves so they can hide

Give an example of where an animal in a tropical rainforest has adapted to thee low-light levels on the floor.

- anteaters have a sharp sense of smell so they can detect predators

Why are some rainforest animals nocturnal?

- they feed at night because it's cooler then => save energy

CASE STUDY: AMAZON RAINFOREST

Location?
What is it?
How large?

- Amazon Rainforest

• South America

• mainly in Brazil but also in: Colombia, Peru, Bolivia, Ecuador, Guyana, Suriname, Venezuela, French Guyana
  

- the Amazon is the largest rainforest on Earth
- covers an area of 8,000,000km²

What is the main cause of deforestation in the Amazon Rainforest?

- commercial farming;

• forest is cleared to make space for cattle grazing or huge plantations (cattle ranching is no. 1 cause, 65-70%)
  - e.g. soy, rice, corn and sugar cane

What is the 2nd biggest cause of deforestation in the Amazon?

- subsistence farming (20-25%);

• forest is cleared by small-scale farmers who need land to grow food for themselves and their families
  - many indigenous people are subsistence farmers

What is the 3rd biggest cause of deforestation in the Amazon?

- commercial logging (2-3%);

• the Amazon is full of valuable hardwood trees such as mahogany
  => logging is extremely tempting for both legal and illegal businesses

What are the other 4 minor causes of deforestation in the Amazon?

- mineral extraction; explosives are sometimes used to clear earth
- energy development; building hydroelectric dams floods large areas of forest
- population growth and migration to the area; poor people are offered land in the rainforest
- road building; areas have tobe cleared for the new roads built for logging

How is climate change an environmental impact of deforestation in the Amazon?

- trees remove CO₂ from the atmosphere
- burning the trees releases carbon dioxide from the fire but also from the carbon dioxide that used to be stored in the trees

How is soil erosion another environmental impact of deforestation in the Amazon?

• less tree canopy to intercept rainfall + fewer tree roots to absorb the water => more water reaches the soil => reduces soil fertility as nutrients in the soil are washed away
  

• commercial & subsistence farmers are then forced to find new areas with more fertile soil to farm => further deforestation

What positive economic impacts does the deforestation in the Amazon have?

- economic development, farming in particular, has brought wealth to many Amazonian countries

- the mining industry creates jobs for people

- logging contributes hugely to Brazil's economy

What negative economic impacts does the deforestation in the Amazon have?

- logging can however, also destroy resources that countries depend on, e.g. timber
- logging also reduces the attractiveness of the area to tourists

• local Brazilian rubber tappers (extract natural rubber from rubber trees) have lost their livelihoods as trees have been cut down

In what ways are tropical rainforests valuable to people and the environment?

PEOPLE:

- many products, including rubber, coffee, chocolate and medicines, are sourced from the rainforest

ENVIRONMENT:

- sustainable development => long-term benefits (e.g. ecotourism)
- protection => may reduce greenhouse effect by reducing carbon dioxide emissions, and allowing trees to continue absorbing CO₂
- climate change could affect all countries not just where deforestation is actually happening
- rainforests help regulate the climate and water cycle => without them, the risk of drought and flooding in certain areas could increase

What is sustainable development within the rainforest?

- management of the rainforest in a way that we get the resources that we need today, without damaging the environment so that resources aren't available in the future

How can selective logging be used to manage the rainforests sustainably?

- only some trees (e.g. older ones) are felled => most trees remain

• overall forest structure is kept => allows forest to regenerate (smaller, younger trees can still grow)

How can afforestation be used to manage the rainforest sustainably?

- new trees are planted to replace the ones that are cut down (the same type of tree is replanted)

How can ecotourism be used to manage the rainforests sustainably?

- minimises damage & benefits local people => provides a source of income for the locals => don't have to log/farm to make money => fewer trees are cut down

- only a small number of visitors are allowed into an area at a time + rules are imposed to minimise environmental impacts (e.g. waste/litter are disposed of properly)

- can also raise awareness of conservation issues + bring in more money to help protect rainforests

How can education be used to manage the rainforests sustainably?

- educating international community about impacts of deforestation => encourage people to buy products from sustainable sources

- informs local people, who might damage the forest without realising the long-term effects of their actions

- teaching locals about alternative ways to make money that do not damage the rainforest

How can conservation be used to manage rainforests sustainably?

- many countries have set up national parks and nature reserves within rainforests => damaging activities are restricted

- money can be used to enforce restrictions on damaging activities & promote sustainable use of the rainforests

How can reducing debt be used to manage rainforests sustainably?

- LICs often borrow money from wealthier countries or organisations (money must be paid back with interest => poorer countries log, farm and mine to make money to pay back the debt)

- a reduction in debt means countries don't have to damage the rainforest => rainforests can be conserved

• conservation swap; part of a country's debt is paid off in exchange for a guarantee that the money will be spent on conservation

How can international hardwood agreements be used to manage the rainforests sustainably?

- high demand for hardwood from consumers in rich countries => some tropical hardwood trees are becoming increasingly rare

- international agreements have taken place to try to prevent illegal logging and to promote the use of hardwood from sustainably managed forests

• e.g. the Forest Stewardship Council (FSC) mark sustainably-sourced timer with their logo so that consumers can choose products that do not contribute to unsustainable deforestation

How can conservation groups balance economic development with conservation?

- conservation groups, e.g. Greenpeace and the WWF, pressure governments to protect environments => can lead to more sustainable development that doesn't damage at-risk areas

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What is an ecosystem?

- all the biotic and abiotic parts of an area

What are the 3 classes of the organisms in an ecosystem?

- producers
- consumers
- decomposers

What does a consumer do?

- a consumer is an organism that gets its energy by eating other organisms, including producers or other consumers

What is a decomposer, and its role in the ecosystem?

- a decomposer is an organism that gets its energy by breaking down dead material (fallen leaves) and dead consumers (animal remains)

• - e.g. bacteria and fungi

What does the nutrient cycle show?

- the nutrient cycle shows how nutrients move through an ecosystem

What does a food chain show?

- a food chain shows what's eaten by what in an ecosystem

What does a food web show?

- a food web shows multiple interlinked food chains and how they overlap

What would happen if there was a decrease in the number of prey?

• What is this called?

- whole food chain is affected
- predator has less food => some predators die
- less predators => increase in the number of prey again

• interdependence