TROPHIC LEVEL QUESTIONS
1)
2)
3)
4)
5)
6)
Describe how energy gets passed around within
an ecosystem.
List and describe the differences between the
five ways organisms get their energy. (producer,
herbivore, etc.)
Describe the differences between a food chain
and a food web. Which is more accurate and
why?
What are the tropic levels?
Describe the 10% rule and why this occurs.
TBA (at the end of the slideshow)
TROPHIC LEVELS
How energy gets around and ecosystem.
ENERGY TRANSFER
Each time an organisms eats another organisms,
energy transfer occurs.
 Food chains, food webs, and trophic levels tell us
how energy transfer occurs.
 Each step in the chains or webs represent the
transfer of energy.
 Each time energy is transferred from one level to
another, some energy is lost as heat and less energy
is available for organisms at the next level.

PRODUCER
Makes it’s own food
through photosynthesis.
 Example: grasses, ferns,
trees, algae

HERBIVORE
Energy comes from
producers.
 Example: cow, sheep,
deer, grasshoppers

CARNIVORE
Get energy from
other consumers.
 Example: lions,
hawks, spiders,
sharks, whales

OMNIVORE
Get energy from both
producers and consumers
 Example: bears, pigs,
gorillas, rats, cockroaches,
humans

DECOMPOSER
Breaks down dead organisms
in an ecosystem and returns
nutrients to soil, water, and
air.
 Examples: fungi and bacteria

FOOD CHAINS

Food chain: sequence in which energy is transferred
from one organism to another.
FOOD WEBS

Show many feeding
relationships that
are possible in an
ecosystem.
Quaternary
consumers
• Trophic Levels
Carnivore
Carnivore
Tertiary
consumers
Carnivore
Carnivore
Secondary
consumers
Carnivore
Carnivore
Primary
consumers
Zooplankton
Herbivore
Producers
Plant
Figure 19.21
A terrestrial food chain
Phytoplankton
A marine food chain
CONSUMERS

Organisms which eat other organisms to
obtain energy.
1. Primary Consumer: eats producers
2. Secondary Consumer: eats primary
consumers.
3. Tertiary Consumer: eat secondary
consumers
4. Quaternary Consumer: Eat Tertiary
consumers
Quaternary,
tertiary,
and
secondary
consumers
Tertiary
and
secondary
consumers
Secondary
and
primary
consumers
Primary
consumers
Producers
(plants)
Figure 19.23
10% RULE
90% of the energy at each trophic level is used to
carry out functions of living.
 Only 10% is available to the next trophic level.
 http://www.brainpop.com/science/energy/energypyr
amid/

What happens to energy as you go up trophic levels? Why?
Tertiary
consumers
10 kcal
Secondary
consumers
100 kcal
Primary
consumers
Producers
1,000 kcal
10,000 kcal
Figure 19.26
6)

The feeding relationships in an ecosystem
– Think of a ecosystem and 12 organisms that
live in it. Create a food web and include at
least one organism for each trophic level.
(Show who eats who.) Also label 6 abiotic
factors that are part of your ecosystem.
12.3 QUESTIONS 1-6
POSTER ASSIGNMENT




Draw an Ecosystem with 12 organisms.
Include at least one from each trophic level
(producers, primary, secondary, tertiary,
quarternary consumers, and decomposers).
Show who eats who.
List 6 abiotic factors that are part of your
ecosystem. On the back, describe how they
affect organisms in the ecosystem.
Include at least 1 ecosystem cycle (water,
nitrogen, and/or carbon cycle). Provide
description of cycle on back.
(You will be presenting these to the class!!!)