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How Can We Assess Human Impact?

How Can We Assess Human Impact?. Text 2.2: 68 - 84. Agenda. Demo – If Earth Were an Apple Primer – United Nations Environment Programme Assessing Impacts on Ecosystems Assessing Soils Assessing Water Quality Assessing Organisms Inquiry & Demo – Bioaccumulation

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How Can We Assess Human Impact?

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  1. How Can We Assess Human Impact? Text 2.2: 68 - 84

  2. Agenda • Demo – If Earth Were an Apple • Primer – United Nations Environment Programme • Assessing Impacts on Ecosystems • Assessing Soils • Assessing Water Quality • Assessing Organisms • Inquiry & Demo – Bioaccumulation • STSE – Increasing Biodiversity in Your Community

  3. Learning Goal • By the end of the class I can • Determine a method for assessing human impact on the environment.

  4. Demo - If the World Was an Apple…

  5. Why Do We Assess the Impacts? To provide leadership and encourage partnerships in caring for the environment by inspiring, informing, and enabling nations and peoples to improve the quality of life without compromising that of future generations.

  6. How Do We Assess the Impacts? • We need to find ways of assessing effects of human impact on soils, water, and organisms. • Helps us to find ways to prevent harm to the ecosystem. • Helps us find ways to improve the health of ecosystems that have been damaged by human activities.

  7. How Do We Assess Soils? • Soil is a loose covering on the ground containing a mixture of organic matter, minerals, and moisture. • To assess soil quality we look at three components 1) Soil profile, 2) Soil type, 3) Acidity • Each main soil type supports different varieties of plants, with loam being preferred for agriculture. • Most plants prefer a neutral pH environment = optimal pH zone

  8. How Do Humans Impact Soils? • Soil erosion – the loss of soil when water or wind washes or blows it away caused by overgrazing, ploughing, tilling, and intensive agriculture. • Crop rotation is a practice that helps reduce nutrient loss by planting a different crop in a particular field each year. • Plants such as soybeans, peas, lentils, alfalfa have a symbiotic relationship with nitrogen-fixing bacteria in their nodules.

  9. How Do Humans Impact Water Quality? Dissolved Oxygen – measurements give the level of oxygen present in water • Healthy aquatic ecosystems are full of organisms • Types and quantities of species present in the water can indicate the state of water quality. i.e. beaches closed in summer • Different organisms prefer different conditions Biological oxygen demand (BOD) – measures how quickly oxygen is used up by micro-organisms in a given body of water

  10. How Do Humans Impact Water Quality? • As acidity increases diversity of plants and animals decrease. • Neutral = best e.g. fish die if the water’s pH falls to 4.5 • Run-off from fields, storm sewers, gardens, and roads carry high levels of nutrients can cause overload. • Overload = Eutrophication is the addition of nutrients to an aquatic ecosystem causing increased plant growth of plants such as algae.

  11. How Do Humans Impact on Organisms? • Pesticides are chemicals that kill unwanted organisms, usually ones that attack crops and reduce yield. • Some last a long time in the environment i.e. heavy metals, DDT • Bioaccumulation – gradual build-up of a substance in an organism’s body. • Biomagnifiction – toxin becomes more and more concentrated each link in the food chain as one animal eats many contaminated animals.

  12. Demo - Bioaccumulation • We will simulate how bioaccumulation happens with a tropic level. • Select 14 volunteers • 8 zooplankton • 4 large fish • 2 eagles

  13. Inquiry – Impact of Bioaccumulation? • Use the following website to determine three types of bioaccumulation and fill in the chart. • Research one type of Persistent Bioaccumulative, Persistent Organic Pollutant or Toxic Pollutant • Describe how it affects the organism. http://www.eoearth.org/article/bioaccumulation

  14. STSE – Increasing Biodiversity in Your Community • In groups of 3-4 complete the STSE A15 p.g. 81

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