Trophic Levels and Food Chains The producers, consumers, and decomposers of each ecosystem make up a food chain. There are many food chains in an ecosystem. Food chains show where energy is transferred and not who eats who.

Example of a Food Chain – Simple…

Trophic Levels and Food Chains Quaternary consumers Food Chain: Set of food (energy) transfer from trophic level to trophic level Carnivore Carnivore Tertiary consumers Carnivore Carnivore Secondary consumers Carnivore Carnivore Primary consumers Herbivore Zooplankton Producers Plant Phytoplankton A terrestrial food chain A marine food chain

Food Webs – Complex Quickly… Fig 6.5 Food web of the harp seal.

Quaternary, tertiary, and secondary consumers Tertiary and secondary consumers Secondary and primary consumers Primary consumers Producers (plants)

Decomposers What is a decomposer and what do they do? What trophic level would you put them at? Derive their energy from the dead material left by all trophic levels Are often left off of most food chain diagrams

Trophic Levels A trophic level is the position occupied by an organism in a food chain. Producers are found at the base of the pyramid and compromise the first trophic level. Primary consumers make up the second trophic level. Secondary consumers make up the third trophic level. Finally Tertiary consumers make up the top trophic level.

Trophic Levels Found on an Energy Pyramid Trophic levels can be analyzed on an energy pyramid. The greatest amount of energy is found at the base of the pyramid. The least amount of energy is found at top of the pyramid.

Plant material eaten by caterpillar Does all the energy this caterpillar eats get passed to the bird who eats him? Plant material eaten by caterpillar 100 kilocalories (kcal) 35 kcal Cellular respiration 50 kcal Feces 15 kcal Growth Figure 19.25

Pyramid of Energy A diagram that represents the cumulative loss of energy from a food chain

What happens to energy as you go up trophic levels? Why? Tertiary consumers 10 kcal Secondary consumers 100 kcal Primary consumers 1,000 kcal Producers 10,000 kcal Figure 19.26\

Pyramid of Numbers A diagram that represents the actual number of organisms present at each trophic level

Pyramid of Numbers 1

Pyramid of Numbers 2

Pyramid of Numbers 3

Biomass Energy is sometimes considered in terms of biomass, the mass of all the organisms and organic material in an area. There is more biomass at the trophic level of producers and fewer at the trophic level of tertiary consumers. (There are more plants on Earth than there are animals.) Bio=life Mass=weight Bio + Mass = Weight of living things within an ecosystem.

Pyramid of Biomass vs. Pyramid of Numbers

Pyramids