Survey
* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project
Download iGCSE Biology Section 4 lesson 4
Document related concepts
no text concepts found
Transcript
IGCSE BIOLOGY SECTION 4 LESSON 4 Content Section 4 Ecology and the Environment a) The organism in the environment b) Feeding relationships c) Cycles within ecosystems d) Human influences on the environment Content Lesson 4 d) Human influences on the environment d) Human influences on the environment 4.11 understand the biological consequences of pollution of air by sulfur dioxide and by carbon monoxide 4.12 understand that water vapour, carbon dioxide, nitrous oxide, methane and CFCs are greenhouse gases 4.13 understand how human activities contribute to greenhouse gases 4.14 understand how an increase in greenhouse gases results in an enhanced greenhouse effect and that this may lead to global warming and its consequences 4.15 understand the biological consequences of pollution of water by sewage, including increases in the number of micro-organisms causing depletion of oxygen 4.16 understand that eutrophication can result from leached minerals from fertiliser 4.17 understand the effects of deforestation, including leaching, soil erosion, disturbance of the water cycle and of the balance in atmospheric oxygen and carbon dioxide. Air Pollution Air Pollution Air Pollution Smoke Sulphur dioxide Air Pollution Smoke Sulphur dioxide Lead compounds Carbon monoxide Oxides of nitrogen Air Pollution SMOKE Consists mainly of tiny particles of carbon and tar which comes mostly from burning coal. Particles blacken buildings and damage the leaves of trees. Much reduced since the Clean Air Act of 1956 Air Pollution December 1952 Smoke + Fog = Smog Cold fog, together with the smoke from many coal fires, caused a ‘pea-souper’. Officials believe that as many as 12,000 people in London may have died as a result of the smog. Air Pollution SULPHUR DIOXIDE and OXIDES OF NITROGEN Coal and oil contain sulphur and nitrogen. When these fuels burn, they release sulphur dioxide (SO2) and oxides of nitrogen (NO, NO2) Air Pollution SULPHUR DIOXIDE and OXIDES OF NITROGEN These oxides can react with water in the atmosphere to form acids (sulphuric acid H2SO4 and nitric acid HNO3). Air Pollution SULPHUR DIOXIDE and OXIDES OF NITROGEN These acids then fall back down to the ground as ACID RAIN. The nitrogen oxides are also produced from car exhausts. Air Pollution Gases react with water in the atmosphere to form ….. Sulphur dioxide and nitrogen oxides ACID RAIN Nitrogen oxides Industry and power stations Motor cars Air Pollution Gases react with water in the atmosphere to form ….. Sulphur dioxide and nitrogen oxides ACID RAIN Nitrogen oxides Industry and power stations Motor cars Acid rain damages trees directly, and also affect lakes and rivers, making them too acidic for plants and animals Air Pollution Carbon monoxide Air Pollution Carbon monoxide Haemoglobin O2 O2 O2 O2 Air Pollution Carbon monoxide CO Haemoglobin O2 O2 O2 O2 Air Pollution carboxyhaemoglobin Carbon monoxide Haemoglobin CO CO CO CO understand that water vapour, carbon dioxide, nitrous oxide, methane and CFCs are greenhouse gases What is a greenhouse gas? A greenhouse gas is any gas in the atmosphere that contributes towards the greenhouse effect (global warming). Carbon dioxide Nitrous oxide CFCs Greenhouse gases Water vapour Methane So what is this ‘greenhouse effect’? The Greenhouse Effect The Greenhouse Effect The Greenhouse Effect The Greenhouse Effect Earth’s surface absorbs energy … and warms up The Greenhouse Effect Warm surface radiates energy back Earth’s surface absorbs energy … and warms up The Greenhouse Effect A proportion of the long waves is absorbed by the atmosphere Warm surface radiates energy back Earth’s surface absorbs energy … and warms up The Greenhouse Effect If the concentration of any off the greenhouse gases were to increase, the greenhouse effect would be increased and the Earth would get warmer. The Greenhouse Effect If the concentration of any off the greenhouse gases were to increase, the greenhouse effect would be increased and the Earth would get warmer. Records show that the concentration of CO2 has increased from 0.029 to 0.035 per cent since 1860. it is likely to go on increasing as we burn more and more fossil fuel. The Greenhouse Effect • DEFORESTATION – reduces photosynthesis which removes CO2 (also reduces the rate at which carbon dioxide is ‘locked up’ as wood) • Burning - either chopped-down wood or industrial produces CO2 • increased micro-organism activity – on decaying material produces CO2 • herds of cattle – produce methane, CH4 • Rice fields also produce methane The Greenhouse Effect • DEFORESTATION – reduces photosynthesis which removes CO2 (also reduces the rate at which carbon dioxide is ‘locked up’ as wood) • Burning - either chopped-down wood or industrial produces CO2 • increased micro-organism activity – on decaying material produces CO2 • herds of cattle – produce methane, CH4 • Rice fields also produce methane Cause increase in atmospheric CARBON DIOXIDE and METHANE The Greenhouse Effect • DEFORESTATION – reduces photosynthesis which removes CO2 (also reduces the rate at which carbon dioxide is ‘locked up’ as wood) • Burning - either chopped-down wood or industrial produces CO2 • increased micro-organism activity – on decaying material produces CO2 • herds of cattle – produce methane, CH4 • Rice fields also produce methane Cause increase in atmospheric CARBON DIOXIDE and METHANE WHICH CAUSES GLOBAL WARMING The Greenhouse Effect The Greenhouse Effect Consequences: • substantial climate changes • a rise in sea level Eutrophication This is the enrichment of natural waters with nutrients which allow the water to support an increasing amount of plant life. Human activity can lead to rapid eutrophication and destruction of aquatic life. Eutrophication A six-stage process Eutrophication A six-stage process 1. Inorganic fertilisers, used by farmers on their crops, may be washed into lakes and rivers. The fertiliser is originally sprayed to replace nutrients that previous crops have removed from the soil. n.b. Untreated sewage has the same effect as excess fertiliser. Eutrophication A six-stage process 1. Inorganic fertilisers, used by farmers on their crops, may be washed into lakes and rivers. The fertiliser is originally sprayed to replace nutrients that previous crops have removed from the soil. n.b. Untreated sewage has the same effect as excess fertiliser. Eutrophication A six-stage process 2. Growth. - of water plants caused by the fertiliser or sewage happens rapidly. The nitrogen in particular is taken up quickly by the plants and used to make protein for growth of new and existing shoots. = ALGAL BLOOM Eutrophication A six-stage process 3. Death – of some of these plants due to lack of light from overcrowding. The plants literally choke themselves to death as they try to gain sufficient light from the Sun, and more nutrients from the water. Eutrophication A six-stage process 4. Micro-organisms which feed on dead organisms now increase massively in number. These are the putrefying bacteria which breakdown dead organic material via respiration, and release simpler substances for recycling. Eutrophication A six-stage process 5. Oxygen – is used up quickly by this huge number of microorganisms. The process of breakdown is respiration, i.e. the micro-organisms respire the organic material and use oxygen in doing so. Eutrophication A six-stage process 6. Suffocation – of fishes and other aquatic animals due to lack of oxygen in the water. Eventually almost all oxygen is removed from the water, so there is insufficient for larger organisms, and they subsequently die. Eutrophication A six-stage process 6. Suffocation – of fishes and other aquatic animals due to lack of oxygen in the water. Eventually almost all oxygen is removed from the water, so there is insufficient for larger organisms, and they subsequently die. understand the effects of deforestation, including leaching, soil erosion, disturbance of the water cycle, and of the balance in atmospheric oxygen and carbon dioxide. Deforestation “ … involves the large scale cutting down of trees for timber, and to provide land for agricultural uses.” Deforestation Leaching Water cycle Soil erosion Effect on atmosphere Deforestation Leaching Water cycle Soil erosion Effect on atmosphere Deforestation Leaching Water cycle Removal of the trees exposes the soil beneath directly to rain, which washes nutrients out of the soil into surrounding streams and waterways Soil erosion Effect on atmosphere Deforestation Leaching Water cycle Soil erosion Effect on atmosphere Deforestation Leaching Water cycle The soil is physically removed from its location and washed down into streams and rivers where it will accumulate (silt) and effectively block waterways. Soil erosion Effect on atmosphere Deforestation Leaching Water cycle Soil erosion Effect on atmosphere Deforestation Leaching Water cycle With trees present, much transpiration occurs through the leaves into the atmosphere. When trees are cut down this water movement is stopped. Soil erosion Effect on atmosphere Deforestation Leaching Water cycle Soil erosion Effect on atmosphere Deforestation Leaching Water cycle Photosynthesis in the leaves of trees maintains the balance in the atmosphere between oxygen and carbon dioxide. Removing trees disrupts this delicate balance. Soil erosion Effect on atmosphere Deforestation http://www.global-greenhouse-warming.com/deforestation.html Deforestation Every second, an area of rainforest equivalent to two U.S. football fields is destroyed. http://www.global-greenhouse-warming.com/deforestation.html End of Section 4 Lesson 4 In this lesson we have covered: • the effects of human activity on the environment • air pollution • acid rain • carbon monoxide poisoning • the greenhouse effect • eutrophication • deforestation
