Energy Flow Food Chains and Webs Energy Transfer

Energy Flow: Food Chains and Webs

Energy Transfer Energy transfers from one organism to another when they are consumed and metabolized. Energy can be followed based on how organism obtain energy. Trophic levels – the position of an organism in a sequence of energy transfer Trophic levels are depicted in food chains.

Food Chains and Food Webs A food chain is a single pathway of feeding relationships in an ecosystem Draw the following food chain! Feeding relationships are much more complex than a simple food chain. This complexity is shown through a food web. Add on to the chain in a food web!

10% rule Every time energy is transferred from one organism to another, not all of the energy is passed on. In fact, more often than only a very low portion of the energy is transferred. On average, only 10% of the total energy consumed in one trophic level is passed on to the next level. Why?

Biomass Because so little of the energy is transferred from trophic level to trophic level, the higher trophic levels can only support a limited number of organisms. This is because they must consumer a greater number of organisms to reach the amount of energy they need to survive. This is why an ecosystem will have less carnivores than herbivores. For example in Africa there about 1000 herbivores for every lion.

Biological Magnification The low energy transfer in each trophic level can lead to some serious consequences in the higher trophic levels. Biological magnification is the increase of a substance in food chains or webs due to the low transfer of energy which leads to the need for consumption of a greater number of organisms at the high trophic levels.

Food chains and webs Create a food chain Use 4 organisms and the sun Use arrows in one color to show the flow of energy Label each organism with its trophic level Show much energy is in each level Label them with what type of producer or consumer they are (herbivore, carnivore, etc) Make it a food web Add 6 more organisms to your chain to make it a web Use arrows in a second color to show the flow of energy Label them with what type of producer or consumer they are (herbivore, carnivore, etc) Explain the 10% rule and biological magnification in your own words on the back