Food Chains to Food Webs Journals Begin by
Food Chains to Food Webs - Journals • Begin by writing/drawing your food chain down the middle of a page in your Environmental Science journal • After you’ve walked around the room, add at least 6 organisms from your classmates’ food chains • Additions must come from (at least) two different food chains. • Make a legend indicating which group (one name OK) the new organisms came from (see board)! • Be sure their level in the food web is accurately reflected!
Stream Chemistry and Modeling/Management Unit 1: The Hydrosphere
Chemical Parameters for Streams • Dissolved Oxygen • p. H • Alkalinity • Phosphates/Nitrates • Chloride • Most are measured in ppm or mg/L • What is 1 ppm? (0. 000001 or 0. 0001% as compared to water)
Dissolved Oxygen • Review – absorbed through gills or skin • Dissolved oxygen is higher when… • More turbulence (mixing with the air) • Lower temperature • More photosynthetic organisms • Less organic pollution
p. H and Alkalinity • Review: p. H has a unique scale of…representative of the concentration of Hydrogen atoms in solution • Determined by precipitation (acidic), other inputs, and alkalinity of the stream • Most prefer 6. 5 -8. 2, will die at lower than 5 • Alkalinity – ability of streams to buffer an acidic p. H • Presence of a limestone (Ca. CO 3) bedrock
Phosphates and Nitrates • Phosphorus – important nutrient for DNA and ATP (energy) • Phosphorus cycle – rocks break down and release phosphates (PO 43 -) • Nitrogen – important nutrient for DNA and proteins • Cycles through a variety of non-/useable forms via the Nitrogen Cycle • Too much of either can lead to eutrophication caused by runoff of manure and fertilizers, air pollution, and wastewater treatment discharge
Chlorides • Found to a greater extent in salt water (salts like Na. Cl dissolve) • Enter through weathering of minerals, industrial discharge, or runoff from farms or roads (de-icing compounds) • As you get closer to the sea, there’s more mixing between salt and fresh water • Organisms are adapted to only living on salt or fresh water
Modeling and Management • Will discuss and apply more after our test (? ) • Studies often begin in the field, but eventually scientific models are used • Require simplifications and testing • Changes in management (which you can manipulate in a model) can be assessed in a model • Can take this data to governing bodies • What might be the downside of a model?
Stations Review Activity – to come before the test • Groups of 3 or 4 (no exceptions) • Move to the station, don’t bring the station to you • 5 minutes per station – we will track • While you wait to move to the next station – how might this information be tested? • Take notes as you go!
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