P1 Section B: The Living World
Global Biomes:
Climate graphs show
temperature and precipitation
The line shows the temperature
The bars shows precipitation
What is the climate like in certain biomes?
Rainforest
Tundra
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UK small scale ecosystem: a pond
Energy is lost moving up the ecosystem as animals respire of defecate.
Factors affecting small scale ecosystems:
Nutrient Cycling: interdependence
How are nutrients recycled in an ecosystem?
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P1 Section B: Rainforests
The Structure of a Rainforest
EMERGENTS or Top Canopy – 30-60m
Shrub layer and ground layer (less than 5m)
Canopy – 15-30m
UNDER or Lower tree canopy – 5-15m
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40
35
30
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20
15
10
5
0
Decreasing fertility
Increased Leaching of nutrients by rainwater
Soils – High Iron content, thick leaf litter layer
Some trees are fast growing to “emerge” above forest canopy and capture sunlight e.g. Capoc
Eagles, bats, monkeys and butterflies can live up here
Many trees have wide deep BUTTRESS roots. These stabilise the tree, increase surface area for Oxygen/CO2 exchange and help transport water
Liana – a woody plant that takes root in soil but that is supported by trees so it can grow upwards to get sunlight
Drip tip leaves to allow excess water to spill off, prevents leaf damage
Epiphytes – parasitic plants that take root in trees high in the canopy
Plant Adaptations
There is great biodiversity (variety of life) up to 100 in a single hectare. It supports the largest number of plant and animal species of any biome.
Most animals are found in the canopy where there is maximum light (spider monkeys are well adapted to living in trees). Animals such as wild boars live on the forest floor eating seeds and berries.
Leopards have a number of adaptations.
Camouflage to help them hunt small animals in the dense forest. Claws to help them climb trees to hunt monkeys and rest up in the canopy. Powerful jaws to kill animals and survive as a predator.
There are hundreds of frogs in the rainforest, sometimes over 50 species in one area.
Some are poisonous to avoid being eaten by larger animals or birds in the rainforest. Often they are brightly colored to warn animals of this. Some just imitate this colour to trick animals into thinking they are.
There are also many species of birds and birds of paradise.
They often have bright colours to attract mates in order to reproduce as well as strong beaks that can be used to break open nuts that grown in the forest.
Animal adaptations.
Plant adaptations.
Practice Qs:
Suggest why there are high levels of biodiversity in the rainforest [2]
Describe the global distribution of rainforests [3]
Explain how plants have adapted to survive in a tropical rainforest biome [6]
Explain how animals have adapted to survive in a tropical rainforest biome [6]
Suggest how nutrients can be recycled within an ecosystem[6]
Suggest how a small scale ecosystems that you have studied could be impacted by human activity. [4]
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Value of Tropical rainforests:
Palm oil (commercial crop)
Timber e.g. in construction
Dams and reservoirs for HEP
Mining metal ores e.g. copper
Commercial farming for soybeans
Beef cattle ranching
Forests purify the atmosphere – taking in Carbon Dioxide & giving out oxygen purifying the atmosphere.
The rainforest is a life support system for our planet
Trees protect the soil by intercepting rainfall, so their is less surface run off and so less soil erosion.
Forests provide leaf litter which rots down into humus, returning important nutrients to the soil.
Forests create their own rainfall as water evaporates from leaves and as transpiration releases water vapour
Removing CO2, it is a huge carbon sink
Services
Water regulation
Goods/ resources
25% of modern medicined derive from the rainforest.
Rubber tapping
Rates of deforestation in the Amazon are decreasing
Causes of Deforestation in the Amazon:
Comprising about 40 percent of Brazil's total area, it is bounded by the Guiana Highlands to the north, the Andes Mountains to the west, the Brazilian central plateau to the south, and the Atlantic Ocean to the east.
NAMED EXAMPLE: Amazon Rainforest: Brazil.
Characteristics, causes and consequences of deforestation and sustainable management.
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The BR-163 is a 1700km long main road that serves as useful infrastructure to transport good out of the Amazon rainforest. This has improved access for people to carry out illegal logging and encouraged the growth of settlements.
Legal and illegal logging. In 1996, Asian companies invested more than US$ 500 million in Brazil’s timber industry.
Space is needed for villages and towns, as well as farms to grow food to feed and ever growing population. Trees will have to be removed and sometimes land dug up to get services to these settlements too, such as electricity, water and gas. Brazil is a NEE with limited job opportunities so people are pulled to the rainforest for “easy” income.
Hydropower accounts for about 16 percent of the world's electricity, but more than 70 percent in Latin America, particularly in the Amazon basin, where it is more plentiful and cheaper than any other source. This is flooding large areas of rainforest, which will decompose underwater releasing methane.
China is involved in mining projects in the eastern Amazon, ranging from aluminium/steel to nickel/copper.
Subsistence = Farming to feed your family
Commercial = Farming to make a profit cattle ranching is the main cause of deforestation in the Amazon. Providing cheap meat to HICs
Causes of Deforestation in the Amazon :
Forested = Trees can intercept rainfall and absorb water from soil.
Deforested = Soil becomes saturated and landslide occur
Impacts of deforestation in the Amazon:
You need to be able to identify Social, Economic and Environmental effects.
Discuss local and global impacts and impacts on different groups of people.
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REDD
REDD (Reducing Emissions from Deforestation and forest Degradation) is a United Nations project whose purpose is to stop deforestation, by high income countries giving financial incentives life funding or debt reduction to Low Income Nations to conserve their forests rather than deforest.
Selective logging or partial forest removal is the practice of cutting down a few species of trees while leaving the rest intact and unharmed. It aims to keep the canopy intact, protect biodiversity and reduce soils erosion.
But, a lack of trained officials to enforce and monitor the system across the Brazil has led to the continuation of abuses and illegal activities. Measures, such as replanting, have not always been carried out satisfactorily. Deforestation is still taking place where land is being converted into oil palm plantations.
Ecotourism benefits the economy and environment by employing local people and using local produce, so profits stay in the local community. It provides money for the local area whilst educating people in conservation and so not damaging the environment. However, it is small-scale as ecotourism is an expensive option for travellers, as a result the impact is limited. E.g. The Posada Amazonas eco-lodge in Peru where local people earn 60% of profit. 18 local people are employed in roles ranging from cleaning to guides. All waste is recycled.
Sustaineble Management:
Forest Stewardship Council
The Forest Stewardship Council (FSC) is an international organisation that promotes sustainable forestry. Products that have been sourced from sustainably managed forests carry the FSC label. The FSC aims to educate manufacturers and consumers about the need to buy wood from sustainable sources. It also aims to reduce demand for rare and valuable tropical hardwoods.
NAMED EXAMPLE: Amazon Rainforest: Brazil.
Characteristics, causes and consequences of deforestation and sustainable management.
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Vegetation e.g. acacia trees
Diurnal temperature range +40 in the day -20 at night!
Hot deserts are found in all continents apart from Europe. Examples include the Thar, Arabian and Gobi in Asia, Namib and Sahara in Africa. They are found in areas of high pressure due to dry air descending
Landscape
Low precipitation <250mm a year
P1 Section B: Hot Deserts
Interdependence in Hot Deserts: adaptations
Interdependence (relying on other things) between the different components of hot deserts is essential for
life to thrive. These are:
, , , ,
.
The biotic components that live in the hot desert are connected to each other and the physical environment .
climate
water
soil
plants
animals
people
The Cacti and Aloe [pictured] has fat fleshy leaves to store water. It has roots that spread out over a wide area and stay shallow to catch as much water as possible when it rains. Spines stop animals from eating it that are searching for water.
To stay cool a Bilby digs underground.
It is nocturnal so it avoids daytime heat
It can cope with drought because it takes moisture from food
Eucalyptus trees:
Shed leaves in drought to prevent water loss
have few stomata to reduce transpiration
use deep roots to reach groundwater
only germinate when it is the rainy season
Kangaroos have adapted to jump instead of run which is an efficient way to travel that loses less energy. They also only mate in the rainy season when there is an abundance of food and water.
Acacia trees are found in our study location of the Thar desert.
It shares many adaptations of the Eucalyptus but also has spikey branches to prevent transpiration and predation. Their large canopy creates shade too which encourages growth around it.
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Opportunities
Challenges
As the climate changes, average temperatures become higher, increasing evaporation. This moisture is then carried away by trade winds. Higher temperatures make it harder for plant life to survive, exposing the soil causing it to erode faster.
The Thar desert is one of the major hot deserts of the world it covers 200,000km2 and is mostly in the Indian state of Rajasthan. It is the most densely populated desert in the world with a population of around 78,000 (Sheffield 250,000).
Mineral Extraction
Gypsum - used in making plaster and cement for the construction industry. At Jaisalmer, Sanu limestone is the main source of limestone for India’s steel industry. Valuable reserves of marble are quarried near Jodhpur, to be used in the construction industry. The Thar desert also has feldspar (used in the construction industry), phosphorite (used in fertilisers) and kaolin (used as a whitener in paper).
Energy
Extensive coal deposits and a thermal energy
plant has been constructed at Giral
Bhaleria solar power plant uses the ideal sunny, cloudless skies, for solar power generation.
In the Barmer district a large oilfield has been discovered which could transform the local economy. India’s largest wind farm, the Jaisalmer wind Park, was constructed in 2001.
Farming
Rajasthan canal, built in 1958, is 650km long and has made irrigation possible allowing the growing of wheat and cotton
People survive in the desert by grazing animals on the grassy areas and cultivating vegetables and fruit.
Tourism
Desert safaris on camels are a popular attraction. Local people provide food, accommodation and act as tour guides. The Thar Desert has beautiful landscapes. Thousands visit the desert each year, many from Pakistan.
It is a hot/arid climate; total rainfall 313mm/year meaning little water for the large population. High temperatures lead to high evaporation
Commercial farmers often can’t grow enough to sell, so jobs are lost and families pay less tax meaning lower development. There is a lack of water and resources in the area.
The high temperatures can cause the tarmac to melt and the strong winds can cause sand dunes to migrate over roads.
NAMED EXAMPLE: Hot desert – Thar Desert on the boarder of India and Pakistan
Opportunities, challenges, causes and management of desertification.
Many places are only accessible by camel and public transport often involves seriously overladen (busy) buses.
Climate change (Physical)
Soil erosion (Physical)
Soil erosion is increase by human activities like over grazing and cultivation. Depleting the soil.
However the soil is naturally being eroded and weathered. Becoming so dry it is blown away by the wind [saltation]
Population growth (Human)
Populations are increasing in the Thar desert. Putting more pressure on resources e.g. trees for fuel wood. The ground is being over cultivates and water id put under greater stress increasing desertification.
Overgrazing (Human)
An increasing population results in larger desert areas being farmed. Sheep, cattle and goats are overgrazing the vegetation. This leaves the soil exposed to erosion. The animals also trample and break up the ground making it easier to erode.
Because of the increasing population, more food is needed. This means that the soil is over-cultivated (ploughed), resulting in the soil becoming exhausted and infertile. It will turn to dust.
Additionally, the use of chemical fertilizers and pesticides makes the soil more acidic and less fertile.
Over-cultivation (Human)
Deforestation (Human)
Trees shade the soil, regulate the flow of water, release water vapour from their leaves and hold solid together with their roots. Without them the soil is left dangerously dry and loose.
Causes of Desertification:
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Sustainable management of desertification:
The canopy of leaves intercepts (stops) rainfall, from here it falls gently to the ground by dripping from leaf tips. Without this interception, the raindrops would strike the soil and their force can erode small soil particles.
The plants prevent the surface of the soil being baked in the heat. Without vegetation cover more moisture in the soil is drawn upwards and evaporates from the surface.
Roots of plants help to bind the soil together and prevent gulley erosion.
The leaves provide shade. This can reduce air temperatures by up to 20°C than in the open so the soil stays cooler.
Great Green Wall In the Sahel [planting acacia trees.
Environmental benefits
Acacia trees have all the benefits any tree provides; protecting the soil from erosion by regulating water flow and providing shade.
Social benefits:
Local people can harvest from the trees and sell gum arabic to a middle-man who then sells to a larger supplier. This provides vital income
Magic stones “bunds”
Farmers place stones in around the perimeter of their land.
The stones create shade that holds moisture underground
The stones capture soil being transported by saltation, keeping soil in the area.
Drip irrigation or trickle irrigation is a type of micro-irrigation system that has the potential to save water and nutrients by allowing water to drip slowly to the roots of plants, either from above the soil surface or buried below the surface.
NAMED EXAMPLE: Hot desert – Thar Desert on the boarder of India and Pakistan
Opportunities, challenges, causes and management of desertification.
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