Edexcel B Geography Paper 3 Topic 8

State three characteristics of tropical rainforests (3 Marks)

No distinct seasons (1 Mark)

Evergreen trees (1 Mark)

Multiple layers (shrub, understory, canopy, emergent) (1 Mark)

Describe the climate of the tropical rainforest biome (3 Marks)

Very wet with over 2,000 mm of rainfall per year (1 Mark)

Very warm with an average daily temperature of 28°C (1 Mark)

The climate is consistent all year round. There are no seasons (1 Mark)

Explain how biotic and abiotic characteristics are interdependent in tropical rainforests (4 Marks)

There is a warm and wet climate due to the location on the equator (1 Mark), (the explanation) this means that plants grow quickly, (1 Mark) (the explanation) so the dense leaf cover protects the forest floor from wind and heavy rainfall (1 Mark) and (the explanation) the root systems hold the soil together and stops it being eroded (1 Mark)

Identify three features of the rainforest shown (3 Marks)

Very tall trees (1 Mark)

Canopy layer (1 Mark)

Layered or stratified forest structure (1 Mark)

Very dense vegetation growth (1 Mark)

Using your own knowledge, identify two ways in which plants in tropical rainforests are adapted to the climate (2 Mark)

buttress roots

drip tip leaves

Identify one adaptation of tropical rainforest trees to the climate of countries such as Cambodia (1 Mark)

The trees stop some water movement / acting as barrier (interception) (1 Mark)

The trees slow down the movement of water from canopy to ground/soil (1 Mark)

Explain why the climate in equatorial regions, such as Brazil provides excellent conditions for growth (3 Marks)

There are very few limiting factors to growth such as warmth (1 mark), (the explanation) because there is more sunshine hours and high rainfall due to its location close to the equator, (1 mark) (the explanation) and this results in a year-round growing season (1 mark).

Explain one adaptation that tropical rainforest plants have (2 Mark)

(The adaptation) Plants have thick and waxy leaves with pointed tips called drip-tips, (1 Mark)

(the explanation) so these channel the water to a point so it runs off so the weight of the water doesn't damage the plant (1 Mark)

(The adaptation) Trees have buttress roots, (1 Mark) (the explanation) which allow support for the very tall trees reaching for light (1 Mark)

(The adaptation) Epiphytes grow on the branches of tall trees, (1 Mark) (the explanation) so that they are higher up and have more light than on the forest floor (1 Mark)

Explain one adaptation that tropical rainforest animals have (2 Marks)

(The adaptation) Howler monkeys have strong limbs, (1 Mark) (the explanation) so that they can spend all day climbing and leaping from tree to tree in the canopy (1 Mark)

(The adaptation) Leaf-tailed geckos are camouflaged to look like leaves, (1 Mark) (the explanation) so they can hide from predators (1 Mark)

(The adaptation) Sloths are nocturnal (active at night), they sleep through the day and feed at night when it's cooler, (1 Mark) (the explanation) (the explanation) because this helps them to save energy (1 Mark)

Explain why nutrient cycling is so rapid in tropical rainforests (4 Marks)

(The reason) Trees are evergreen, (the explanation) so dead leaves and other material fall all year round (1 Mark) then the warm, moist climate (1 Mark) (the explanation) means that fungi and bacteria can decompose the dead organic matter quickly (1 Mark), (the explanation) so then nutrients released and are soaked up by the soil (1 Mark)

Explain the impact of deforestation on the nutrient cycle (4 Marks)

(The reason) Most nutrients in the tropical rainforest are stored in biomass, (1 Mark) (the explanation) so if forest is cut down most nutrients are destroyed, (1 Mark) (the explanation) so without the forest to protect it, (1 Mark), (the explanation) causing litter and soil to be eroded by heavy rains (1 Mark)

Define what is meant by biodiversity (1 Mark)

Biodiversity means the number of different plant and animal species in an area/ or the range of different species in an area (1 Mark)

Explain why tropical rainforests have such high levels of biodiversity (4 Marks)

(The reason) Tropical rainforests have high levels of biodiversity, (the explanation) because it's hot and wet all year round, (1 Mark) so there is lots of water and warmth, (1 Mark) which means lots of photosynthesis can take place, (1 Mark) leading to lots of primary productivity forming the huge amounts of plant biomass (1 Mark

Explain why food webs in tropical rainforests are so complex (2 Marks)

(The reason) High biodiversity, (1 Mark) (the explanation) so many niches (1 mark)

(The reason) High levels of productivity, (1 Mark) (the explanation) so a large food source (1 Mark)

(The reason) It is a high-energy ecosystem, (1 Mark) (the explanation) so a very high plant biodiversity (1 mark

State three characteristics of the taiga biome (3 Marks)

Low biodiversity compared to other biomes (1 Mark) - if you just put high biodiversity you will not get the mark. You must give it some context by comparing it to other biomes

Distinct seasons (1 Mark) Coniferous trees (1 Mark

Describe the climate of the taiga biome (3 Marks)

Short, wet summers of three months when temperatures can rise to over 20°C (1 Mark) Long, cold, dry winters with several months below freezing, as low as -20° (1 Mark) Snow on the ground for 5 months of the year (1 Mark)

Explain how biotic and abiotic characteristics are interdependent in the taiga biome (4 Marks)

(How they are interdependent) In summer, the trees absorb heat from the sun and shade the ground below, (1 Mark) (the explanation) so this prevents the permafrost below from thawing, (1 Mark) (the explanation) meaning the permafrost can provide water for plants, (1 Mark) (the explanation) so helping them to grow (1 Mark)

State two adaptations of coniferous trees (e.g. spruce, pine) to ensure they can survive (2 marks)

The 'cone' shape (1 Mark)

Branches are flexible and bend downward to take the weight of the snow(1 Mark) Needle-like leaves protected by a waxy coating (1 Mark)

Seeds protected by woody cones (1 Mark)

Shallow tree roots (1 Mark)

Explain one adaptation of trees in the taiga (2 Marks)

(The adaptation) They are evergreen (they don't drop their leaves in a particular season), (1 Mark) (the explanation) so they can make best use of the available light (1 Mark)

(The adaptation) They have needles instead of flat leaves, (the explanation) so this reduces water loss from strong, cold winds as it reduces the surface area.

(The adaptation) They are cone-shaped, (1 Mark) (the explanation) so this means that heavy winter snowfall can slide straight off the branches without breaking them (1 Mark)

State one adaptation that helps many taiga animals to survive (1 Mark)

Thick, oily fur (1 Mark)

Hibernate in the winter (1 Mark)

Migration in the winter (1 Mark)

Layer of insulating feathers (1 Mark)

Explain one adaptation of animals in the taiga (2 Marks)

(The adaptation) Wolves have this fur, (1 Mark) (the explanation) so they are well-insulated against the winter cold (1 Mark)

Explain why the taiga biome has low levels of primary productivity (4 Marks)

(The reason) In the taiga there is a cold, seasonal climate (1 Mark) (the explanation) thus it limits the amount of warmth and light (1 Mark) (the explanation) therefore reducing the amount of photosynthesis, (1 Mark) (the explanation) so there are low levels of primary productivity (1 Mark)

Explain two reasons why nutrient cycling is much slower in the taiga compared to tropical rainforests (4 Marks)

The biomass store in the Taiga is small (1) because trees grow for only a few months each year, reducing the nutrient cycle time span (1)

Precipitation in the Taiga is lower, and chemical weathering is limited (1) because of the cold temperatures (1)

Explain one reason for the low levels of biodiversity in the taiga biome (4 Marks)

(The reason) The taiga has low levels of biodiversity, (the explanation) because it has a cold and very seasonal climate and is not wet all year round, (1 Mark) so there isn't of water and warmth, (1 Mark) which means not much photosynthesis can take place, (1 Mark) leading to little primary productivity forming only small amounts of plant biomass (1 Mark)

Explain two direct threats to tropical rainforests (4 Marks)

(The threat) Local demand for fuelwood, (1 Mark), (the explanation) because they chop down trees to use as fuel for cooking or to burn to make charcoal (1 Mark)

(The threat) Commercial hardwood logging, (1 Mark) (the explanation) because trees are felled to make furniture and for construction (1 Mark)

Explain how foreign debt is causing an increase in deforestation rates (2 Marks)

(How foreign debt is causing an increase) There is a huge market for goods from tropical rainforests, (1 Mark) (the explanation) so it's an easy way for poor countries to make money to pay back the debt they owe to richer countries (1 Mark)

Explain how economic development is causing an increase in deforestation rates (2 Marks)

(How economic development is causing an increase) Road and rail projects to promote economic development, (1 Mark) (the explanation) cause huge areas of the rainforest to be cut down for logging, mining and farming (1 Mark)

Explain why climate change in an indirect threat to the health of the tropical rainforests (4 Marks)

(The changes to climate) Changes change means that temperatures increase and rainfall rates decrease, (1 Mark) (the explanation) which leads to drought, (1 Mark) (the explanation) which then leads to ecosystem stress, (1 Mark) because plants and animals living in tropical rainforests are adapted to moist conditions and therefore many species die in dry weather (1 Mark)

Explain one direct threat to the taiga biome (2 Marks)

(The direct threat) One direct threat is logging for softwood, (1 Mark) (the explanation) because trees are cut down so that they can be made into housing, furniture and matches (1 Mark)

Explain one indirect threat to the taiga biome (2 Marks)

(The indirect threat) In the exploitation of fossil fuels e.g. tar sands, (1 Mark) (the explanation) because trees are cleared to extract gas and oil from the ground (1 Mark)

Explain two ways that climate change that may threaten the biodiversity taiga forests (4 Marks)

(The reason) Increased wildfires, (1 Mark) (the explanation) leading to habitat loss (1 Mark) (The reason) Increased pests/parasites, (1 Mark) (the explanation) causing the wiping out of

some species (1 Mark

Explain one way that acid rain damages the taiga ecosystem (4 Marks)

(The way) Acid rain damages trees/plants by damaging the needles/leaves (1 Mark) (the explanation) which makes it harder for them to cope with the cold (1 Mark), (the explanation) and so reduces their rate of photosynthesis, (1 Mark) (the explanation) so the trees weaken, becoming more susceptible to death or disease (1 Mark)

Explain two global actions which help protect the rainforest (4 Marks)

(The action) CITES stops animal trade, (1 Mark) (the explanation) so helps to protect endangered species (1 Mark)

(The action) REDD provides funding, (1 Mark) (the explanation) which results in forests being protected

State one advantage of CITES in protecting the tropical rainforest (1 Mark)

CITES has changed the way that endangered animal species are traded and has protected many endangered species

State one disadvantage of CITES in protecting the tropical rainforest (1 Mark)

Membership of CITES is voluntary so many countries still trade illegally in endangered species (1 Mark)

State one advantage of REDD in protecting the tropical rainforest (1 Mark)

An advantage of carbon trading is that it could raise money quickly for developing countries (1 Mark)

State one disadvantage of REDD in protecting the tropical rainforest (1 Mark)

A disadvantage is that flooding existing carbon markets with REDD credits could further dilute the already low value of carbon. (1 Mark

Explain one reason why deforestation rates are rising in some areas (2 Marks)

(The reason) Urban poverty forces people to move to rural areas with poor job opportunities, (1 Mark) (the explanation) causing people to get involved in illegal logging (1 Mark)

Explain one reason why deforestation rates are falling in some areas (2 Marks)

(The reason) Forest protection laws, (1 Mark) (the explanation) because there are fines and prosecution for illegal deforestation that means people cut down trees less (1 Mark)

Explain one social challenge of achieving sustainable forest management (4 Marks)

(The social challenge) Sustainable forest management generally provides fewer jobs for local people than conventional forestry, (1 Mark) (the explanation) so many locals won't see the benefits, (1 Mark) (the explanation) so may turn to illegal logging, (the explanation) which is difficult to police (1 Mark

Explain one economic challenge of achieving sustainable forest management (4 Marks)

(The economic challenge) The economic benefits of sustainable management are only seen in the long-term, (1 Mark) so this affects poorer countries, (1 Mark) because they need income immediately, (1 Mark) so they will use more commercial non-sustainable methods instead (1 Mark)

Explain one environmental challenge of achieving sustainable forest management (4 Marks)

(The environmental challenge) When the trees are replanted, the new forest many not resemble the natural forest, (1 Mark) (the explanation) because the trees are replaced but the entire ecosystem may not be restored, (1 Mark) (the explanation) because of the biodiverse nature of the biome, (1 Mark) (the explanation) and the complexity of the food webs of the biome (1 Mark

Explain one way that alternative livelihoods is a better way to protect the remaining tropical rainforest (4 Marks)

(One way) Ecotourism employs local people in tourism, (1 Mark) (the explanation) so they don't have to log or farm to make money, (1 Mark) this means that fewer trees are cut down, (1 Mark) (the explanation) because there is an incentive to not cut down trees (1 Mark)

(One way) Sustainable farming in the form of agro-forestry plants trees and crops at the same time, (1 Mark) so the tree roots bind the soil, (1 Mark) which protects the soil from erosion and

Explain one way that alternative livelihoods is a better way to protect the remaining tropical rainforest (4 Marks

(One way) Ecotourism employs local people in tourism, (1 Mark) (the explanation) so they don't have to log or farm to make money, (1 Mark) this means that fewer trees are cut down, (1 Mark) (the explanation) because there is an incentive to not cut down trees (1 Mark)

(One way) Sustainable farming in the form of agro-forestry plants trees and crops at the same time, (1 Mark) so the tree roots bind the soil, (1 Mark) which protects the soil from erosion and

the leaves protect crops from the impacts of heavy rain (1 Mark), whilst also planting many trees to support the ecosystem (1 Mark

Explain one challenge of conserving the taiga using national parks (2 Marks

(The challenge) Wilderness areas in Taiga forests cover a huge area, (1 Mark) (the explanation) so many of them are very difficult to police and enforce protections (1 Mark