Unit 3.3

 What happens to energy stored in body tissues when one organism eats another?  The energy moves from the “eaten” to the “eater”. Where the energy goes literally depends on who eats whom.

 In every ecosystem, _________________________________ are linked through feeding relationships.  Energy flows

 A food chain is  In most ecosystems the feeding relationships are much more complex than a simple chain, a more realistic idea is a network of feeding interactions called a feeding web.

 There tend to be simple food chains within more complicated food webs.  ______________________________________ are as important in food webs as other consumers! ◦ They are able to convert dead and rotten material into nutrient rich matter that can be used by producers. ◦ Therefore continuing the cycle of life!

 Because of the complexity of a food web, _____________________________________ _____________________________________ _____________________________________ ◦ What if there is an oil spill? How will the death of one organism affect the web as a whole.

 Each step in a food chain or web is called a ________________________. ◦ Primary producers always make up the first trophic level.  One way to illustrate the different tropic levels in an ecosystem is with an ___________________________________________. ◦ Ecological pyramids show the relative amount of energy or matter within each level.

 Pyramids of energy show the relative amount of energy available at each trophic level of a food chain or web.  The efficiency of energy transfer from one level to the next is about ________.

 The total amount of living tissue within a given trophic level is called its biomass.  Biomass is

 A pyramid of biomass illustrates _____________________________________ _____________________________________ _____________________________________  A pyramid of numbers shows _____________________________________ _____________________________________ _____________________________________

 In some cases, ___________________________________________ __________________________________________. ◦ Thousands of insects may graze upon a single tree.  This would change the shape of the pyramid, turning it upside down.