7th Grade Chapter 1 Lesson 2 pgs. 9-14


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7th Grade Chapter 1 Lesson 2 pgs. 9-14

  1. 1. 7 th Grade Chapter 1 Lesson 2 Pgs. 9-14 For student use only
  2. 2. Your Back Yard <ul><li>Your backyard is full of organisms </li></ul><ul><ul><li>Organisms - living things </li></ul></ul><ul><li>All organisms live in an environment . </li></ul><ul><ul><li>Environment - all conditions, influences and surroundings of an organism or group of organisms </li></ul></ul>
  3. 3. Your Back Yard <ul><li>Physical Features of the ENVIRONMENT </li></ul><ul><ul><li>Air </li></ul></ul><ul><ul><li>Water </li></ul></ul><ul><ul><li>Soil </li></ul></ul><ul><li>Soil is very important to the environment! </li></ul><ul><ul><li>All plants get nutrients from soil and soil determines what types of plants grow in the environment. </li></ul></ul>
  4. 4. Your Back Yard <ul><li>Soil: </li></ul><ul><ul><li>Pedology- study of soil </li></ul></ul><ul><li>Soil is made of: </li></ul><ul><ul><li>Minerals- material not from living organisms </li></ul></ul><ul><ul><li>Organic material- material derived from living organisms </li></ul></ul>
  5. 5. Your Back Yard <ul><li>Organic Material: </li></ul><ul><ul><li>Formed from decomposition of once living material </li></ul></ul><ul><ul><li>Broken down by worms, bacteria, fungi, other organisms </li></ul></ul><ul><ul><li>This decomposed, processed material is humus . </li></ul></ul><ul><ul><ul><li>Humus - black or brown, nutrient rich material in soil that holds water </li></ul></ul></ul>
  6. 6. Your Back Yard <ul><li>Organic Material- </li></ul><ul><ul><li>Some farmers add organic material (manure or plow under fields) to their crops or compost material </li></ul></ul><ul><ul><ul><li>Compost material- kitchen scraps, shredded paper towel and other organic material that is left in a pile to biodegrade </li></ul></ul></ul><ul><ul><ul><li>Composting is a way to recycle (use again) materials </li></ul></ul></ul>
  7. 7. Your Back Yard <ul><li>Organic Material </li></ul><ul><ul><li>Topsoil- is mostly organic material and is found in the top 2 – 6 inches of soil </li></ul></ul><ul><ul><li>Organic material makes up 4% to 5% of soil. </li></ul></ul><ul><ul><li>Peat is all organic material that is found in wet, boggy places. </li></ul></ul>
  8. 8. Your Back Yard <ul><li>Minerals: </li></ul><ul><ul><li>Rock pieces in soil from weathering. </li></ul></ul><ul><ul><ul><li>Weathering - can be physical or chemical and is the breaking down of rocks </li></ul></ul></ul><ul><ul><li>The type of weathering and rock determine the particle size and composition of soil. </li></ul></ul><ul><ul><li>Weathered rocks become subsoil . </li></ul></ul><ul><ul><ul><li>Subsoil - lower than the topsoil, less organic, and full of rock pieces. </li></ul></ul></ul>
  9. 9. Your Back Yard <ul><li>Minerals: </li></ul><ul><ul><li>Below the subsoil is the bedrock . </li></ul></ul><ul><ul><ul><li>Bedrock - layer of solid rock and the foundation for other layers. This layer is not weathered! </li></ul></ul></ul>
  10. 10. Your Back Yard <ul><li>Weathering </li></ul><ul><ul><li>Physical- breaks down rocks by physical things like water, wind, and temperature into sands and silts (made of quartz) </li></ul></ul><ul><ul><ul><ul><li>NOTE: Quartz is the most common mineral in the earth’s crust! </li></ul></ul></ul></ul><ul><ul><li>Physical weathering breaks rocks into small pieces. This breaking off of small pieces is called exfoliation . </li></ul></ul>
  11. 11. Your Back Yard <ul><li>Chemical Weathering: </li></ul><ul><ul><li>Decomposition of rocks when reacting with other materials such as oxygen, water and acids. (very slow process) </li></ul></ul><ul><ul><ul><li>Ex. Carbonic Acid (CO2 reacting with water) and acids are also produced by mosses and lichens </li></ul></ul></ul><ul><ul><li>Changes the composition (make up) of the rock (physical weathering just breaks into smaller pieces) </li></ul></ul>
  12. 12. Your Back Yard <ul><li>Erosion: </li></ul><ul><ul><li>When wind, streams, or ice carry away fragments of rock from weathering. </li></ul></ul><ul><ul><li>Fragments are carried to the ocean or the land. </li></ul></ul><ul><ul><li>Plants help prevent erosion by holding soil with their roots. </li></ul></ul>