48hr+Food+Web

 1) From the list of foods you’ve consumed in the 48hr period, write all of the //components// of that food in their simplest form. For example: Bread à wheat, eggs, yeast, sugar, water, salt. 2) Once you’ve done this cross out items that are from non-living sources. (salt, water) 3) Now, look through your list and write a “P” next to all producers, 1o next to all primary consumers, 2o next to all secondary consumers, etc. Write an “A” next to all apex consumers. 4) Look at your list to determine how many levels are in your food chart. For example if you consumed nothing above the primary consumer level, you have three levels. 5) (This part can be done either electronically - saving a tree or on paper if you prefer. Steps 5-10) Start a new page on this wiki and label it with your name and 48hr food web, OR get a piece of A3 paper and write a title on it to represent your 48hr food web. Divide the paper up into the appropriate number of levels and label each level. 6) Starting from the bottom, write down all of the producers from your list. Write all of the primary consumers in the next division above. Continue until all items involved in your list are used. 7) Examine your list. Are there any items “missing”? For example if you had beef, are the typical food items for the cow included on your chart (grass, corn)? If not, add them to the appropriate level. Write these in another color/style so we know they were add-ons. 8) Add any other organisms that might participate in these feeding relationships to any level until you have at least 50 total organisms represented on your diagram. 9) Now, using a ruler, make vertical links in your diagram to indicate the flow of energy. Lines may cross or “skip” through a division. Lines may also go to more than one organism above. Make arrowheads on the lines to indicate the direction of energy flow. 10) Using highlighter, highlight two different food chains.
 * Developing your 48hr food web. **

Analysis: (mail your answers to me) 1) What is a Kilocalorie? How do we use this measure? 2) What is a “keystone species”? Do you have any keystone species in your food web? How would the loss of this species impact your food web? 3) Considering only the foods you actually consumed, which level do you find most of your kcalories come from? Some people (see the discussion on the "Values" page) suggest that it is wasteful to eat “higher on the food chain”. Research this idea and prepare an argument either supporting or rejecting this claim.