Trophic Levels:

Trophic Levels: = an organism’s position in the food chain... …what it eats and what eats it...

What the “Levels?” Primary producers  = producers / autotrophs 1◦ = Primary consumers eat primary producers: herbivores 2◦ = Secondary consumers eat primary consumers: carnivores and omnivores  3◦ = Tertiary consumers eat secondary consumers 4◦ = Quaternary consumers eat tertiary consumers Food chains "end" with top predators, animals that have little or no natural enemies

Place a “1°” under any consumer that can act as a primary consumer… Remember this? Place a “1°” under any consumer that can act as a primary consumer… A “2°” under any consumer that can act as a secondary consumer… A “3°” for tertiary consumers… And a “4°” for quaternary consumers… Label the ‘primary producer’ Maple Millipede Salamander Snake Hawk

1° 3° 4° Primary Producer Primary Consumer 2° Secondary Consumer Maple Millipede Salamander Snake Hawk Primary Producer 1° Primary Consumer 2° Secondary Consumer 3° Tertiary Consumer 4° Quaternary Consumer

Examples of Feeding Relationships

From which trophic level do secondary consumers get their energy? Explain how the energy from the sun gets passed to ALL organisms in a food web.

The amount of energy in an ecosystem can be shown using a pyramid which illustrates the amounts of energy within each trophic level Draw this! Least energy Most energy

Why do you think there is such a big difference? Energy Pyramid: Lets look at the number of species in the lower trophic levels and compare it with the number of species in higher trophic levels. Why do you think there is such a big difference?

Think about how many individual insects could be supported by one individual tree… We usually compare trophic levels by how much total energy the trophic level contains rather than the total number of organisms in a trophic level

Least energy Most energy There really is no limit to the numbers of trophic levels that a food chain can support….but, only part of the energy stored in one trophic level is passed on to the next level…it takes energy to sustain life!

10% Rule in Ecology…. ~10% of the energy in one trophic level is passed to the next trophic level

10% 90% lost as heat

10% 90% lost as heat

10% 90% lost as heat

How much energy is left at each level? 1000 Cal ? Cal

1000 Cal 100 Cal 10 Cal 1 Cal 9 Cal as heat 90 Cal as heat 900 Cal as heat

10% Rule Question Why do you think only 10% of the total energy from 1 trophic level is passed to the next?

Why do you think only 10% of the total energy from 1 trophic level is passed to the next? 3 reasons: Energy is “used up” for daily life activities Not all organisms that die are eaten by animals in the next trophic level Not all parts of an organism are eaten and digested for energy

Review about energy flow: 2. How does the amount of energy change as it passes through an ecosystem? 3. What is the source for all energy in an ecosystem?

Answers! 2. How does the amount of energy change as it passes through an ecosystem? The amount of available energy decreases as it passes to higher trophic levels 3. What is the source for all energy in an ecosystem? All energy in an ecosystem can be traced back to the sun