Energy Flow Through Biological Communities

Food Chains (trophic levels)

Detritivores: Scavengers & Decomposers

• Scavengers animals that obtain energy from dead and waste matter breaking it into smaller pieces (ex. vultures, earthworms, lobsters, beetles, maggots)

• Decomposers obtain energy from dead and waste matter breaking it down into chemical parts which can be reused again by producers. (ex. bacteria and fungi)

Food Web = sum of food chains in a community

Energy Transfer is Inefficient

What percent of the energy from the plant material becomes caterpillar biomass?

Energy Pyramid (10% rule)

Energy loss limits the number of trophic levels

Decrease in Energy = Decrease in Matter

Decrease in Energy = Decrease in Matter

An experimental fish farm consists of algae, crustaceans that eat the algae, and fish that eat the crustaceans. If the algae grow at a rate of 20 kilograms of algae per square meter of pond per year, how big will the pond have to be to harvest 1,000 kilograms of fish per year? (Assume that energy content is proportional to biomass). Show your work!

10% Rule Practice Problem

The 10% Rule Explains Why Meat is a Luxury

Biological Magnification: toxins increase in concentration in a food chain as biomass decreases