Topic 1 - ESS answers

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1 Topic 1 - ESS answers Page 14 Environmental value system Environmental management strategies Environmental philosophies Labels and characteristics Social movements Politics Ecocentric Anthropocentric Technocentric Emphasizes a less materialistic approach to life Greater self-sufficiency of societies Small scale local community Ecology and nature are central to humanity Humans are not the only species Life has an inherent value for its own sake Earth is here for all species Nurturing / life-centred Respects the rights of nature Emphasizes the dependence of humans on nature Holistic view of life, which is Earth-centred Consider it arrogant to think humans can manage the complex system of nature Cannot all have a high standard of living Resources are limited Must work within Earth s limits Environmental protection groups E.g. Greenpeace campaigns against whaling, Friends of the Earth, local environmental movements Use of taxes, environmental regulation and legislation to protect the environment and resources Humans control and manage resources Believes humans must sustainably manage the global system If we look after the planet it looks after us Human-centred Humans are not dependent on nature but nature is there to benefit humankind Manipulative There will always be more resources to exploit Economic growth is good so should continue Stewardship Earth is a garden to be tended Ethical duty to protect and nurture the Earth E.g. anti-nuclear bomb activists Population-limitation movements Green parties. Free market economy but with strong government intervention Environmental managers Use of technology to solve environmental problems Believes that technological developments can provide solutions to environmental problems Technology-centred Intervening Human are the dominant species Earth has infinite resources Human inventiveness will solve all problems Growth provides the answers Earth is a space ship and humans the captain and crew E.g. climate change solution groups using technology such as mirrors in space, carbon capture Free market economy Capitalism with minimal government control 1

2 Page 20 Examples of systems An ecosystem is a good example of a system. Using the model below, draw your own systems diagram for: a) A candle oxygen manufacture wax wick combustion vapour carbon dioxide b) A mobile phone electrical sound data collection raw materials of the phone exchange signals c) A green plant CO 2 minerals photosynthesis sugars plant material respiration oxygen green wavelength chemical d) You food oxygen assimilation chemical respiration carbon dioxide waste e) Your school people books money knowledge assimilation buildings books furniture education educated students waste material money f) A lake rainfall surface runoff sediment precipitation/flow plants rocks / soil surface runoff / evaporation 2

3 Page It was called Biosphere 2 probably because it was modelled on the Earth which was the first biosphere. 2. A closed system exchanges but not matter with the environment. 3. Terrestrial Marine Tropical rainforest Coral reef Savanna grassland Mangrove wetlands Fog desert Mangrove wetlands Page 24 Compare these two models Shows three systems separately but with Shows environment incorporating the other overlapping areas two systems Has clear annotations to explain what the No annotations areas mean Shows a small area where all systems Does not show what is sustainable overlap as being sustainable Shows what happens when pairs of areas overlap Why are any of these circles in the Venn diagram outside the environment? The Venn diagram model suggests that some social and economic decisions are made without consideration for the environment. If environment is the natural environment only then some social and economic interactions are not within the natural environment. Students may be able to think of others they should justify their comments clearly. Is culture relevant to these models of sustainability? Where would you draw it in? This is a matter of opinion students should draw where they think culture should be and justify it. One answer is that culture should be around everything in both these models because it impacts our attitudes to all systems. Does the model change how we treat our environment? If we look at these models carefully it should stop and make us think about how we treat the environment the idea that everything is interconnected. Evaluate these models. (Consider their strengths and weaknesses.) Very clear explanation of what each of the Shows that the environment is the most systems means important thing and that everything happens within the environment Very clear explanation about what is Allows freedom to interpret it how you happening in the overlapping areas want very simple It acknowledges that some things may happen outside of the natural environment It gives people an excuse to believe some things we do may not impact the environment Ignores culture Too simple so people with no background will not be able to understand what it is showing Ignores culture 3

4 Page A system is a set of inter-related parts working together to make a complex whole. 2. An open system exchanges matter and with its surroundings (eg an ecosystem). A closed system exchanges but not matter. (The Biosphere 2 experiment was an attempt to model this. These systems do not occur naturally on Earth, although the biosphere (or Gaia) itself can be considered a closed system.) An isolated system exchanges neither matter nor. All ecosystems are open systems, because of the input of solar and the exchange of matter with other ecosystems. 3. Burning candle Boiling kettle A plant Animal population Inputs Heat / fire Heat Light Births Page 36 Outputs Energy and material transfers Energy and material transformations 1. Around 10 years. 2. Around 10 years. Oxygen Heat Light Heat (flame s air) Wax: candle puddle of wax Heat Wax: solid liquid Wick: Solid ash Heat Steam / Heats air Fuel steam CO 2 Minerals Oxygen Green Heat environment Glucose plant parts Light chemical Inward migration immigration Food Deaths Out-migration emigration Feces Urine Movement of Excretion Predation Eating plants Chemical Decomposition 3. The snowshoe hare is the food source for the lynx so for lynx numbers to increase there have to be plenty of snowshoe hares. Then when lynx numbers increase they eat more of the snowshoe hares so the snowshoe hare numbers decrease. Fewer snowshoes hares = less food for the lynx, so then the lynx numbers decrease. 4. There have to be fewer predators than prey due to the second law of thermodynamics entropy increase and is lost from the food chain as. This means that each lynx has to eat several snowshoe hares to gain enough to live. Things are never as straightforward in ecology as we expect though. In regions where lynx died out, hare populations still continued to fluctuate. Why do you think this was? If there are too many hares they will overgraze the vegetation and numbers will fall due to food shortages. Once numbers drop and the grass recovers then the snowshoe hare numbers will increase again. 4

5 Page 37 Example 1. As carbon dioxide levels in the atmosphere rise the temperature of the Earth rises. As the Earth warms the rate of photosynthesis in plants increases, more carbon dioxide is therefore removed from the atmosphere by plants, reducing the greenhouse effect and reducing global temperatures. 2. As the Earth warms: Ice cover melts, exposing soil or. Albedo decreases (albedo is the fraction of that is reflected by a body or surface). More is absorbed by Earth s surface. Global temperature rises. More ice melts. 3. As Earth warms, upper layers of permafrost melt, producing logged soil above frozen ground. Methane gas is released in an anoxic environment. The greenhouse effect is enhanced. Earth warms, melting more permafrost. 4. As Earth warms, increased evaporation produces more clouds. Clouds increase albedo, reflecting more away from Earth. Temperature falls. Rates of evaporation fall. 5. As Earth warms, organic matter in soil is decomposed faster: More carbon dioxide is released. Enhanced greenhouse effect occurs. Earth warms further. Rates of decomposition increase. 6. As Earth warms, evaporation increases: Snowfall at high latitudes increases. Ice-caps enlarge. More is reflected by increased albedo of ice cover. Earth cools. Rates of evaporation fall. 7. As Earth warms, polar icecaps melt releasing large numbers of icebergs into oceans. Warm ocean currents such as Gulf Stream are disrupted by additional fresh input into ocean. Reduced transfer of to poles reduces temperature at high latitudes. Ice sheets reform and icebergs retreat. Warm currents are re-established. Type of feedback Positive Positive Positive 5

6 Example of negative feedback there is no feedback arrow because the balance is re-established and the change stops As carbon dioxide levels in the atmosphere rise the temperature of the Earth rises. As the Earth warms the rate of photosynthesis in plants increases More carbon dioxide is removed from the atmosphere by plants, Reducing the greenhouse effect Reducing global temperatures Example of positive feedback the feedback arrow comes back to the start and change continues As Earth warms, organic matter in soil is decomposed faster More carbon dioxide is released. Rates of decomposition increase. Enhanced greenhouse effect occurs. Earth warms further. Page a) There are too many herbivores so they overgraze the vegetation. This causes their numbers to fall due to food shortages. Once numbers drop and the grass recovers then the herbivore numbers will increase again. b) The systems is being stabilized. The output of the process (overgrazing) reverses the operation (increased number of herbivores) so that the change is counteracted. 2. Global warming causes the Earth to warm and this may cause the upper layers of permafrost to melt, The soils above the permafrost become logged. logging causes an anoxic environment and decomposition then releases methane gas. Methane is a greenhouse gas and so the greenhouse effect is enhanced. 6

7 3. solar radiation and in-migration of seed dispersal precipitation and rivers soil and rocks pollution from humans humans sound stores nutrients in the soil and rocks nutrients in plants and chemical plants,, humans long-wave radiation (to space) dispersal of seeds/ out-migration of soil erosion and leaching minerals mined by humans waste products pollution air,, sound rivers, evaporation Quick review answers 1 B 2 B 3 C 4 D 5 C 6 D 7 D 8 B 9 D 10 A 7