people and the biosphere

What is an ecosystem?

A grouping of plants and animals that interact with each other and their local environment

What is a biome?

A large ecosystem; a grouping of plants and animals over a large area of the Earth

What are 5 biomes?

1. Taiga

2. Temperate biome

3. Tundra biome

4. Tropical biome

5. Desert biome

Characteristics of the Taiga biome?

• At higher latitudes where the Sun’s rays are weak

• Trees are adapted to the cold with needle-like leaves

Characteristics of the temperate biome?

• Have high rainfall and there are seasonal variations in the Sun’s rays

• Trees lose their leaves in the cool winters

Characteristics of the Tundra biome?

• Within the Arctic Circle

• The Sun gives little heat here and there is little rainfall

• Only tough, short grasses survive

Characteristics of the Tropical biome?

• Mostly found either side of the Equator

• The temperature is hot and there is heavy rainfall

Characteristics of the Desert biome?

• Close to the tropics of Cancer and Capricorn

• Where hot dry sir sinks down to the Earth’s surface and Sun’s rays are concentrated, making it very hot in the day

How does altitude affect where biomes are found?

• Different plants grow at different temperature within the same biome

• The higher the altitude, the lower the temperature

How does rock and soil type affect where biomes are found?

Can affect how fertile different areas are within a biome

How does drainage affect where biomes are found?

• Swamps + bogs occur where drainage is poor

• Fewer, more specialist plants grow in boggy areas

What are examples of biotic factors? (living)

• Plants (flora)

• Animals (fauna)

What are examples of abiotic factors? (non-living)

• Soils

• Rocks

• Water

• The atmosphere

What is biodiversity?

The variety of biotic components in an ecosystem

(high biodiversity = thousands of different plants + animals)

What is an example of how biotic and abiotic factors interact?

Taiga biome has a low biodiversity → long, cold winters, low precipitation (abiotic) → only specialist plants that can tolerate poor soils and low light (biotic)

What are 4 main ways the biosphere provides resources for people?

1. Food from the biosphere

2. Medicine

3. Fuel resources

4. Building materials

How does the biosphere supply food?

• Fish + meat are part of the biosphere

• Sustainable harvesting of fruits

• Natural vegetation can be replaced with crops like wheat and rice

How does the biosphere supply medicine?

• The periwinkle plant is used to treat leukaemia

• The aloe plant has soothing properties

• Poppies are the source of the painkiller morphine

How does the biosphere supply fuel resources?

• Animal dung is dried and burnt as fuel

• Wood from trees and shrubs

• Biofuels convert plant products to fuel through a range of different processes (eg. bioethanol) made by fermenting crops like sugarcane

What is an example for how the biosphere increasingly exploited for its resources?

The demand for some fish species has led to overfishing and huge declines in fish numbers

What does the biosphere do for us? (3 main things)

1. It regulates the water cycle — plants slow the flow of water to rivers, and filter water to make it clean

2. Regulates the gases that make up the atmosphere — plants absorb carbon dioxide and produce oxygen to breathe in

3. Keeps soil healthy for plants to grow — new nutrients are provided by rotting plant material

What 3 main factors increase resource demand and how?

1. Urbanisation — as more people move to cities, there is a greater need for water

2. Industrialisation — factories need large amounts of water and raw materials to operate

3. Affluence (wealth) — wealthier people use more energy and water as they can afford more appliances

What is Thomas Malthus’ theory?

• It was impossible to increase food production as rapidly as population growth

• If a population grew too much, food supply would run out and result in reducing the population size

What was Ester Boserup’s theory?

• Human innovation will be sparked by demands on resources

• So if there is a high demand for food resources, new techniques to increase food production will be invented

What do climate graphs and nutrient cycle diagrams show?

Climate graphs:

• Climate characteristics

Nutrient cycle diagrams:

• Interdependencies between biotic and abiotic factors

What are the top 3 plant adaptations?

1. The dense forest canopy blocks out light.

   • Some trees, called emergents, are 40m and grow 10m above the canopy

2. Mould grows on all wet surfaces — this blocks sunlight from leaves.

   • Most plants have evolved drip tips that channel water off the leaf

3. Nutrients are concentrated in only the top layer of the soil. This means tree roots have to be shallow.

   • Buttress roots give the tall trees extra stability

What are adaptations of taiga plants?

• Needle-shaped leaves — taiga trees do not drop their leaves. This is to maximise photosynthesis throughout the year. This also reduces water loss

• Cone-shaped — many taiga trees have downwards facing branches to shed heavy snow

• Few species; a simple ecosystem structure — few plants can deal with taiga extremes. Coniferous trees dominate, plus lichens. Trees grow close together to reduce wind damage

What are 3 examples of taiga animals?

• The moose — large taiga herbivore. It can eat pine needles

• Brown bear — large carnivore/omnivore. They build fat layers in summer for hibernation in winter dens

• Non-migrating animal species often have coats or feathers that turn white in winter for camouflage and extra warmth

What happens in the rainforest nutrient cycle?

• Plants grow all year in huge numbers

• Dead matter drops to the forest floor and decomposes quickly in the warm, wet conditions

• Fast-growing plants take up the nutrients very quickly

• The constant precipitation leaches nutrients down through deep rainforest soil

What happens in the taiga nutrient cycle?

• Plants can only grow in the short summer (3-5 months)

• Litter accumulates because decomposition only happens in summer

• Soils are thin + low in nutrients + acidic

• Plants grow very slowly due to short growing season and low-nutrient soil

What are causes of tropical rainforest deforestation?

• Biofuels

• Mining

• Agricultural

  • subsistence

  • commercial

• Commercial hardwood logging

• Wood for fuel

• Electricity

How does global warming threaten the tropical rainforest? (5 ways)

• Warming global temperatures could cause a shift in the atmospheric system that constantly brings wet weather to tropical rainforests

  • makes rainforests drier and hotter

• Tropical rainforest plants and animals have evolved to constant temperate conditions; they cannot tolerate heat spikes

• Tropical rainforest plants are not able to tolerate long droughts

• Stressed plants and animals have less resistance to disease

• Drier forests are at risk of reforest fires

What are 2 causes of deforestation and how they lead to it?

1. Biofuel

   • Can be produced from crops (palm oil)

   • Because of its high demand, farmers can make a lot of money by clearing forest and planting oil palm plants

2. Subsistence agriculture

   • When poor people clear the forest to plant crops to feed themselves and their family

   • Rainforest soils quickly lose their nutrients when forest cover is cleared

What are direct threats to the taiga?

• The conifer trees of the taiga produce softwood timber.

• Direct threats come from logging for softwood, pulp and paper production

What are indirect threats to the taiga?

• Mining for minerals and fossil fuels

• Threatened when dams are created for hydroelectric power schemes which flood forested valleys

Why is biodiversity in the taiga at risk?

• Animals like the Siberian tiger have heavy fur coats and high levels of body fat, making them heat intolerant

• Warmer winter temperatures will allow new disease and pests to spread to the taiga. Taiga animals + plants will not have resistance to these, so species could die out

• Forest fires — taiga species are not adapted to frequent fires; nee trees need many years to grow

What is CITIES and what does it do?

Convention on International Trade in Endangered Species of Wild Fauna end Flora

• Protects 35,000 different species

• Countries that sign up to CITIES agree to stop exports or imports of endangered species

What are is an advantage and disadvantage of CITIES?

Advantage:

Had a huge international influence: 181 countries have signed up

Disadvantage:

Very difficult to check that all the countries are enforcing the CITIES rules. (eg. in 2014, 1000+ things were killed by poachers in South Africa)

What is REDD and what does it do?

Reducing Emissions from Deforestation and Forest Degradation

• Supports schemes that reduce the rate of deforestation

• The United Nations monitors the schemes by the use of remote sensing

What are is an advantage and disadvantage of REDD?

Advantage:

• Backed by the United Nations, so very large sums of money are available for their projects

• A REDD scheme in Brazil is backed by a US$1 billion fund

Disadvantage:

• Not clear what REDD means by ‘forest’

• Some palm tree plants received REDD funding, even though these damage rainforests

What is sustainability?

The ability to keep something going at the same rate or level. It must:

• Keep you without using up natural resources

• Not require lots of money to keep it going

• Meet the needs of people now and in the future without having a negative effect

What are advantages of sustainable biosphere management?

• Ensures the ecosystem can recover quickly from any use

• Prevents damage to the environment/ecosystem

• Helps local people benefit from their environment/ecosystem

• Helps local people understand why this management benefits them

What are possible economic tensions of sustainable tropical rainforest management?

• Individuals and communities often want to make as much money as possible, and may use the resources in the biosphere to do this

• This provides tensions as it may damage or destroy the environment in long term

• Some businesses may flourish at the expense of others

What are possible social tensions of sustainable tropical rainforest management?

• Must not benefit one group at the expense of another, including future generations

• Must consult people on an equal basis

• If everyone is to benefit, this puts the environment as risk

What are possible environmental tensions of sustainable tropical rainforest management?

• Must not harm natural resources so they can’t regenerate or continue in the long term

• This can conflict with making money and improving living standards for all

Why protect the taiga?

• Plants grow very slowly because of the lack of nutrients + cold winters

• Pollution remains in the ecosystem for decades

• There are very few species in the taiga. A disease that affects one species impacts the whole ecosystem

• Taiga animals + plants are highly specialised. They will struggle to adapt to climate change

What areas prevent any exploitation of natural resources?

• Conservation protects plants and animals by looking after and restoring their natural habitat

• Scientific research finds out more about the ecosystem, how it’s threatened and how best to protect it

• Education informs visitors about the taiga and why it should be protected