TOPIC: The Living World Slide 1: Biotic and abiotic parts of an ecosystem

Transcription

1 TOPIC: The Living World Slide 1: Biotic and abiotic parts of an ecosystem Key idea: Ecosystems exist as a range of scales and involve the interaction between biotic and abiotic components. What is an ecosystem? A community of plants and animals that interact with each other and their physical (natural) environment What are the biotic components of an ecosystem? The living parts. Examples? Plants, animals, humans. What are the abiotic components of an ecosystem? The non-living parts. Examples? Climate (temperature and precipitation (rainfall)) Soil What is an ecosystem? (2marks) Give one abiotic component of an ecosystem. (1mark)

2 TOPIC: The Living World Slide 2: Key words to do with ecosystems Producer: A green plant that is able to produce its own food using the suns energy through the process of photosynthesis. Consumer: A creature that eats animals and/or plants. Decomposer: An organism that breaks down dead tissue, which is then recycled to the environment. Examples are: Bacteria and fungi. Food chain: The connections between plants and animals that eat each other. Food web: A complex hierarchy of plants and animals relying on each other for food. Explain the function of decomposers in an ecosystem. (2marks) Explain the function of producers in an ecosystem. (2marks)

3 TOPIC: The Living World Slide 3: An example of a small scale UK ecosystem: Deciduous Woodland Epping Forest Abiotic characteristics of the Epping Forest ecosystem: 1. Climate: Warm summers and cool winters not too hot and not too cold! Plenty of precipitation throughout the year. 2. Soils: The type of soil is called a brown earth soil because of its red brown colour. There is a thick, nutrient rich upper layer with lots of humus because of all the decomposing leaves. Biotic characteristics of the Epping Forest ecosystem: 1. Vegetation: 4 layers of vegetation: 1. The tallest trees such as oak and beech can reach 30m tall. 2. Smaller trees such as birch for a layer below them. 3. Shrub layer including brambles and hawthorn. 4. Ground layer includes plants such as bracken and ferns. Trees are deciduous what does this mean? They lose their leaves in winter. Describe the biotic characteristics of a small scale UK ecosystem you have studied. (4marks)

4 TOPIC: The Living World Slide 4: An example of a small scale UK ecosystem: Deciduous Woodland Epping Forest Vegetation continued: Epping forest is known for its carpets of spring flowers such as bluebells. These are limited to springtime as for the rest of the year the forest floor is in deep shade once the leaves on the trees have grown. Thick layer of leaf litter on the ground because of the deciduous trees. 2. Animals: Large range of habitats for different animals such as squirrels, rabbits and deer. Large variety of insects and decomposers due to the large layer of rotting leaves on the forest floor. Epping forest food web: Name a producer: Oak tree Remember: the arrow means gets eaten by Name a consumer: Anything else.

5 TOPIC: The Living World Slide 5: Nutrient cycling What is nutrient cycling? A set of processes whereby plants extract minerals (nutrients) necessary for growth from the soil. These nutrients are then passed along the food chain until decomposers return them back to the soil. See next slide. What happens to an ecosystem if one component of the ecosystem changes in one way? You need to show an understanding of the knock on effects of this throughout the ecosystem. For the food web opposite If the number of foxes increased The number of spiders, wood mice and robins would decrease. And the number of beetles and caterpillars would increase. What might cause the numbers of an organism to increase? Less predators eating them, an increase in their food source. What might cause the numbers of organisms to decrease? Disease, an increase in predators eating them, a decrease in their food source. Explain how nutrients are cycles in an ecosystem. (4marks)

6 Nutrients in rainwater are added to the soil Litter: Layer of dead vegetation on the soil surface Plants and animals die Biomass: Plants and animals A diagram showing nutrient cycling: Nutrients taken up by plants through their roots Plants decompose releasing nutrients back to the soil. Leaching: water washes nutrients out of the soil Soil Nutrients are added to the soil by weathering of rock.

7 TOPIC: The Living World Slide 7: The distribution an characteristics of large scale natural global ecosystems What is a global ecosystem? (also called a biome) Very large ecological areas on the Earth s surface where the animals and plants adapt to the particular environment. Biomes usually have similar climate and soil characteristics. Examples include Deciduous woodland, tropical rainforest and hot desert. See the section on Epping forest for the characteristics of deciduous woodland, the section on tropical rainforests and the section on deserts for the distribution of those particular biomes. For the others, see the information on the following two slides. Describe the distribution of hot deserts. (2marks) Describe the distribution of tropical rainforests. (2marks) Describe the distribution of temperate deciduous forests. (2marks)

8 If asked about distribution you must: Try to give a sense of the overall pattern- what do the locations of places with this biome have in common? Mainly near which latitude? Mainly coastal/inland? Mainly on the east or west of continents? Mainly located in particular continents. Try to be specific by using compass directions and naming places.

9 Column 1: Name of the biome. Column 2: Location Column 3: Key characteristics

10 TOPIC: The Living World Tropical Rainforests Slide 10: The physical characteristics of a tropical rainforest 1. Climate: Average temperature is 27 C (High!) Little variation in temperature throughout the year. Annual rainfall is 2000mm or higher. (This is high!) In summary, tropical rainforests are hot and wet. 2. Soils: Tropical rainforests soils are called The distribution of tropical rainforests: Found mainly around the equator and often near the coast. The main locations for tropical rainforests are in South America (Amazon), Africa and in Southern Asia. Smaller areas of tropical rainforests are in northern parts of Australia. Latosols. These are infertile and red in colour caused by the fact that they are rich in iron. There is a thick leaf litter layer at the surface but once nutrients are available they are taken up straight away by the plants leading to the soil being infertile (lacking in nutrients) Heavy rainfall causes some nutrients to be leached out of the soil. Leaching is the carrying away of nutrients by the downwards movement of water through the soil. Describe the climate in tropical rainforests. (2marks) Explain one feature of the soils in tropical rainforests. (2marks)

11 TOPIC: The Living World Tropical Rainforests Slide 11: The physical characteristics of a tropical rainforest: 3. Vegetation and animals: Vegetation is arranged in layers: The tallest layer is the emergent layer These are fast growing trees such as the Kapoc tree which can be 50m tall and stick out above the canopy The second layer is the canopy which is a dense layer of trees reaching 30-40m tall. Below that is the under canopy at about 20m tall. Below this is the shrub layer there are only a few shrubs because of the lack of light. Ground layer again not much vegetation because of the lack of light. See slide for plant adaptations and further vegetation characteristics. Rainforests contain huge biodiversity. What is this? The number and variety of different species in a particular habitat in this case the tropical rainforest. Over 2/3 of the worlds plant species and half of the world s animal species are found here. What are the difficult conditions faced by plants and animals in the tropical rainforest? Poor soils, heavy rainfall, lack of sunlight below the canopy layer. Outline one feature of the vegetation in tropical rainforests. (2marks) Explain how vegetation/animals are adapted to the conditions in tropical rainforests. (6marks)

12 TOPIC: The Living World Tropical Rainforests Slide 12: How are plants adapted to the difficult conditions in the rainforest? How are plants adapted to the poor soils? Plants have shallow roots which spread out over long distances to access nutrients directly from the leaf litter layer. Plants called epiphytes can live on branches high up in the canopy because they get nutrients directly from air and water rather than the soil. How are plants adapted to the lack of sunlight? Epiphytes see above. Emergent trees e.g. Kapoc have buttress roots to stabilise them and enable them to grow tall to reach the sunlight. Lianas are vines which have roots in the ground but climb up other trees to reach the canopy and access the sunlight. Many plants have leaves with flexible bases to they can turn their leaves to get maximum sunlight. How are plants adapted to the heavy rainfall? Leaves have drip tips so heavy rainfall just slides off and doesn t break the plant. Thin, smooth bark on trees allows water to flow easily down the tree trunks. Outline one way in which plants are adapted to the low levels of light in a tropical rainforest. (2marks)

13 TOPIC: The Living World Tropical Rainforests Slide 10: How are animals adapted to the physical conditions? Rainforests provide a variety of food sources throughout the year so they support abundant animal life throughout the year. This can also create challenges: How are animals adapted to the high level of competition for food? Many animals are very specialised and live off a plant or animal that few others eat. For example, parrots and toucans have developed strong beaks to break open nuts. Many animals are able to live up in the canopy which is where most of the food is (fruit, seeds and nuts.) Monkeys and sloths are great climbers so they can access the food. How are animals adapted to escape predators? Because the rainforest has such high biodiversity, animals have many predators. Monkeys and sloths are well adapted to living in the trees. Some animals are poisonous and used bright colours to warn off predators such as arrow frogs. The flying frog has web like feet to enable it to glide through the air to avoid predators. Many animals use camouflage. Explain how animals are adapted to conditions in the rainforest. (4marks)

14 TOPIC: The Living World Tropical Rainforests Slide 14: The interdependence of climate, water, soils, plants, animals and people Interdependence means When different elements of an ecosystem rely on each other for things. E.g. plants need animals and animals need plants. Some examples are Animals need plants for food and plants need animals to disperse their seeds. Plants need soil for nutrients. The soil gets nutrients back from the plant when they die and decompose. Plants need water for growth. Plants release water vapor back into the atmosphere through the process of transpiration, this then increases the amount of condensation and cloud cover in the rainforest which then leads to rain and water being available for plants again through their roots. In this way the rainforest creates its own wet climate. People depend on plants and animals in the rainforest for food. We can live in hope that people will do the right thing and make sure the forests are used sustainably so their benefits are there for future generations to enjoy. Outline one example of interdependence in a tropical rainforests. (2marks)

15 TOPIC: The Living World Tropical Rainforests Slide 15: Issues related to biodiversity: What is biodiversity? The variety of life in the world or a particular habitat. Scientists are very concerned about the loss of biodiversity from deforestation. Even though topical forests cover only twelve percent of the land area of the Earth, they are home to between 50 and 90 percent of the world's species. It is thought that we lose one species a day because of deforestation. This is bad, because we are losing a genetic resource and potential medicines and technologies. Rainforests are a vital source of medicines. It is thought that roughly a quarter of all modern medicines came originally from rainforests, many originally used by indigenous people. An example includes Reserpine, a drug which can be used to treat people with high blood pressure. We also get a huge variety of crops and other products from the rainforests. High biodiversity makes the ecosystem more resilient to change and more likely to survive into the future. What is biodiversity? (1mark) Explain why maintaining high levels of biodiversity is important in tropical rainforests. (4marks)

16 TOPIC: The Living World Tropical Rainforests Slide 16: Changing rates of deforestation: What is deforestation? The chopping down and removal of trees to clear an area of forest. Global rates of deforestation remain high although they are slightly lower than the 1990s. The equivalent of 50 football fields have been lost every minute since the year There were originally 6million square miles of tropical rainforests globally. 2.4 million remain. Rates of deforestation are not the same everywhere. Countries where the rates of deforestation are increasing include Indonesia and Peru Countries where the rate is decreasing include Brazil and Mexico mainly due to vast areas of forest being given protected status. Suggest two reasons why the rates of deforestation vary between different countries. (2marks)

17 TOPIC: The Living World Tropical Rainforests. Case study: Amazon rainforest. Slide 17: The causes of deforestation. 1. Subsistence farming: What is this? Farming to feed your family. The main type of subsistence farming in tropical rainforests is slash and burn where tribes burn an area of forest, use it for farming until the nutrients run out then allow the forest to regrow while moving on to another area. This has been practiced in a sustainable way for generations, however, population growth coupled with less forest available means that the forest is not being allowed sufficient time to recover leading to degradation of the forests. 2. Commercial farming: Cattle: What is this? Rearing animals to sell for a profit. Cattle ranching is huge in the Amazon region. The rearing of cattle is believed to account for 80% of rainforest destruction in the region. As the quality of the land deteriorates because of the lack of nutrients being put back into the soil, ranches have to expand into new areas. 3. Commercial farming: Crops. Which crops are common in the Amazon? Responsible for 10% of deforestation in the Amazon. Palm oil and soy beans. Again, the soil will not sustain the crop for long and the farm has to expand into new areas. Growing sugar cane for biofuels is becoming increasingly important. 1. Outline two causes of deforestation in tropical rainforests. (4marks)

18 TOPIC: The Living World Tropical Rainforests. Case study: Amazon rainforest. Slide 18: The causes of deforestation 4. Logging: What is this? The business of cutting down trees and transporting logs to sawmills. Responsible for 3% of deforestation in the Amazon. (Although land cleared for farmland is not included in this figure) Timber companies are most interested in trees such as mahogany and teak which fetch higher prices. Less expensive trees are often turned to pulp for paper. There are two types: Clear felling is where whole areas of forest are cleared. Selective logging is when only certain trees are taken. 5. Road building: This is a particularly important cause of deforestation as although the land cleared is quite small, building roads then opens up remote areas of the forest to other economic activities such as commercial farming, logging and mining. An example of a key road is the Trans-Amazonian Highway which was built in the 1970s and is 4,000km long. The most damaging roads are those that are concreted as these can be used all year as they don t flood in the wet season. Explain how road building contributes to deforestation in tropical rainforests. (2marks)

19 TOPIC: The Living World Tropical Rainforests. Case study: Amazon rainforest. Slide 19: Causes of deforestation: 6. Mineral Extraction: What is this and which minerals are present in the Amazon? The removal of solid mineral resources from the Earth through mining. Minerals include gold, copper, diamonds, bauxite (from which aluminium is made) as well as coal and oil. The Carajas mine is the largest iron ore mine in the world located in Northern Brazil. Forest has to be clear felled in order to dig out the minerals. 50,000 hectares of land in the Amazon are currently being used for gold mining. 7. Energy development. An unlimited supply of water and ideal river conditions have led to the building of many dams which flood large areas of forest. Dams generate hydro-electric power (HEP) where running water turns turbines and is converted to electricity. Dams may power other activities associated with deforestation. The Carajas iron ore mine is mainly powered by HEP. There are also coal and oil deposits in the Amazon which are exploited. Often the dams have a short life. The rotting submerged forest makes the reservoirs acidic which corrodes the turbines. Suggest one economic activity that may benefit from deforestation in the tropical rainforests. (1marks)

20 TOPIC: The Living World Tropical Rainforests. Case study: Amazon rainforest. Slide 20: Causes of deforestation. 8. Building settlements. All the economic activities so far need workers who need somewhere to live which has led to the growth of settlements in the Amazon rainforest. Forest has to be cleared for land to build these on. Parauapebas is a settlement that has grown up to house workers in the Carajas iron ore mine. 9. Population growth. The over riding cause of deforestation is rapid population growth. People need land to live on, grow their food, create energy etc and this has led to increasing deforestation of the Amazon region to try to allow Brazil to develop. (Brazil is classified as an NEE.)

21 TOPIC: The Living World Tropical Rainforests. Case study: Amazon rainforest. Slide 21: The impacts of deforestation: economic development 1. Economic development: Cutting down trees makes space for economic activities such as commercial farming and mining. Income is generated from these activities e.g Brazil made $6.9billion from cattle trading. Logging, farming and mining create jobs e.g. 50,000 people are employed in gold mining in Peru. The jobs from these activities are a way of raising people s quality of life. Taxes from the economic activities can be spent on improving infrastructure and helping the country to develop. However In the long term, deforestation destroys the resources that countries depend on e.g. timber. The economic benefits of deforestation rarely trickle down to those in need. Corruption, poor governance and inadequate law enforcement often mean that local people (e.g. farmers) are exploited by those in power. Discuss the impacts of deforestation on economic development. (6marks) Suggest one way in which deforestation can benefit a country. (2marks) Outline one possible economic impact of deforestation. (2marks)

22 TOPIC: The Living World Tropical Rainforests. Case study: Amazon rainforest. Slide 22: Impacts of deforestation: soil erosion and contribution to climate change. 2. Soil erosion what is this? The removal of topsoil faster than it can be replaced by the action of wind and water. Cutting down trees exposes the soil to heavy rain which washes it away. (Soil may be eashed into rivers, blocking them and causing floods. Deforestation leads to the loss of most of the nutrients in the ecosystems as in the rainforest the biggest store of nutrients is in the biomass (plants and animals). No leaves are returned to the ground and therefore no nutrients are added to the soil making them more vulnerable to erosion. 3. Contribution to climate change: Deforestation leads to climate change in two ways: A tropical rainforest tree acts as a carbon sink and absorbs around 22.5kg of carbon dioxide each year, taking it out of our warming atmosphere. (Remember carbon dioxide is a greenhouse gas which traps heat in our atmosphere leading to global warming) Destruction of the rainforest through burning accounts for approximately 20% of carbon dioxide released into the atmosphere each year. Explain how deforestation can lead to soil erosion. (2marks) Explain how deforestation can contribute to climate change. (3marks) Outline one possible environmental impact of deforestation. (2marks)

23 TOPIC: The Living World Tropical Rainforests. Case study: Amazon rainforest. Slide 23: The value of the rainforest to people and the environment The value of the rainforest to people: Products we eat: cocoa, sugar, bananas. Products we use: rubber, rope Chemicals from leaves, flowers and seeds used in perfumes, soaps, polishes, chewing gum. Medicinal knowledge of rainforest tribes. 25% of medicines used today are derived from rainforests Less than 1% rainforest plants have been tested for medicinal value. 25% active ingredients from cancer fighting drugs come from organisms only found in rainforest. Homes, source of food and livelihood for people. The value of rainforests to the environment: Air purification: absorbs CO2 combats global warming. Protects against soil erosion. Biodiversity - huge variety of habitats for plants and animals. Explain why the rainforest is important to people. (4marks) Suggest one reason why it is important to look after the rainforests. (2marks)

24 TOPIC: The Living World Tropical Rainforests. Case study: Amazon rainforest. Slide 24: Strategies used to manage the rainforest sustainably: What is sustainability? Actions and forms of progress that meet the needs of the present without reducing the ability of FUTURE generations to meet their needs. There are a number of strategies that we can use to manage the rainforest sustainably: 1. Selective logging and replanting 40 year cycle where trees are identified for felling, only selected trees are cut down then the rainforest is restored, trees replanted and allowed to recover. Example Malaysia s selective management system. Introduced Replanting of areas of forest is possible by collecting seeds, growing saplings then replanting them into the area. One area this has happened is in the Atlantic forest in Brazil. PROS If done properly this is completely sustainable. CONS - Roads need to be built to get to the required trees. Needs careful management and enough time left for forest to recover. What is sustainability? (2marks) Evaluate the strategies used to manage the rainforests sustainably. (9marks) To what extent can tropical rainforests be used sustainably? (9marks)

25 TOPIC: The Living World Tropical Rainforests. Case study: Amazon rainforest. Slide 25: Strategies used to manage the rainforest sustainably: 2. International agreements about the use of tropical hardwoods: FSC Forest Stewardship council products from sustainably managed forests carry the FSC label. FSC tries to educate manufacturers and consumers about the need for sustainable forests. The International Tropical Timber Agreement 2006 restricts the trade in tropical hardwoods to those grown in sustainably managed forests. All of the timber has to be marked with a registration number. PROS These agreements aim to make it much more difficult for people illegally deforesting the rainforest to sell their timber. CONS The high demand for expensive timber such as Mahogany and teak mean it is very difficult to completely stop illegal logging. 3. Debt reduction: What is this? Countries are relieved of some of their debt in return for protecting their rainforests. This is called debt for nature swaps Most of the countries with large areas of tropical rainforests are LICs or NEEs, many with large levels of debt. In 2010, the USA converted 13.5million of debt in Brazil into a fund to protect large areas of tropical rainforest PROS not only is this good for the forests but also enables countries to spend money on improving infrastructure and developing rather than paying off debt. Explain how debt reduction can lead to sustainable management of the rainforests. (3marks) Suggest one way that international co-operation can help make tropical rainforests more sustainable. (2marks)

26 TOPIC: The Living World Tropical Rainforests. Case study: Amazon rainforest. Slide 26: Strategies used to manage the rainforest sustainably: 4. Ecotourism This is responsible travel to natural areas that conserves the environment, provides jobs for local people and often involves education. Ecotourism is small scale involving small groups of people and has minimal impact on the local ecosystem. An example is the Yachana ecolodge in Ecuador which is a small hotel built of local materials where the guests can experience local foods and crafts ad learn about the rainforest. Next door is a college which trains local people in the skills they need to work in the hotel. PROS Ecotourism gives the rainforest an economic value without having to cut it down, in fact in order to make money from ecotourism the forest needs to be protected so people will come. Ecotourism is both environmentally and economically sustainable as jobs are provided for local people. CONS Local people involved in ecotourism activities may lose traditional culture. By its very nature, ecotourism has to be small scale and expensive therefore it cannot solve the huge problem of deforestation of the rainforests. 5. Conservation and Education (goes hand in hand with ecotourism) Conservation protecting the forest This includes the Amazon Region Protected Areas Program (ARPA), where the WWF work with the Brazilian government to protect parks covering 150million acres of forest. Education programmes such as those run by NGOs such as the WWF provide education of local people in how to protect the forest and use it sustainably and provide training for conservation workers. CONS it can be difficult to make people understand the importance of using the forest sustainably when they can gain financially in the short term by cutting down the forest. Explain how ecotourism can contribute to sustainable management of the rainforests. (4marks)

27 TOPIC: Living World Case Study: Tropical Rainforests using a case study of the Amazon Rainforest. Facts Quiz What is the average temperature in the rainforest? 27 C What is the average rainfall? 2000mm or above What is the name of a tropical rainforest soil? Latosol. Which line of latitude are rainforests found close to? The equator. How many of the world s plant species are found here? Two thirds. Name an emergent tree. Kapok Name the type of plant that gets its nutrients from air and water so it can live high in the canopy. Epiphyte. Give another name for the vine like plants in rainforests. Liana

28 TOPIC: Living World Case Study: Tropical Rainforests using a case study of the Amazon Rainforest. Facts Quiz Name a bird that can access foods that are not easy to get for other animals. Parrot can crack open nuts Name an animal who has a good way of escaping predators. Flying frog Name the 7 causes of deforestation in the Amazon Subsistence farming, commercial farming, road building, logging, mineral extraction, HEP (energy generation), settlement, population growth Which economic activity is responsible for 80% of deforestation in the Amazon? Cattle rearing. Which economic activity is responsible for 10% of deforestation in the Amazon? Crop farming. Name a tree that is worth a lot of money. Mahogany or teak Name a road that has been built through the Amazon rainforest. The Trans-Amazonian Highway. Name a mine in the Amazon The Carajas Iron Ore mine

29 TOPIC: Living World Case Study: Tropical Rainforests using a case study of the Amazon Rainforest. Facts Quiz What % of today s medicines are derived from rainforests? 25 Name an area where rainforests have been successfully replanted. The Atlantic Forest in Brazil What does FSC stand for? The Forest Stewardship Council. Name a country that has had part of its debt written off in return for it protecting the rainforests. Brazil. Name an example of ecotourism. The Yachana Ecolodge in Ecuador. Name an NGO responsible for education about conserving the forests. WWF (World Wide Fund for Nature.)

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