Food Web, Energy Pyramids and Trophic Levels with Handout

Based on the graph
what conclusion can
you make?

A.Kingdom Protista
is about to
become extinct.

B.There are an
equal number of
species in
Kingdom Fungi
and Kingdom
Protista.

C.Kingdom Animalia
is the most
diverse kingdom.

D.There are over
300,000 species
of plants.

● Describe trophic levels
● Describe what the arrows represent

on an energy pyramid

● Discuss the transfer of energy

Energy flow in an ecosystem

Ecosystems need constant inputs of
energy!

Most ecosystems get energy from
SUNLIGHT, which enters the ecosystem
via the process of photosynthesis

Energy Pyramids:

Shows the energy flow within
an ecosystem from one
trophic level to the next.
➢ Only 10% moves up
each level

Trophic levels & Food Webs

Tropic Levels:

A level or position in a food chain, food web, or

ecological pyramid

Decomposers
Are a type of organism that break down the
remains and other waste and release simple
molecules back into the environment.

Ex: Fungi, bacteria

➢ Food webs show the interconnections of food chains

within an ecosystem.

Producer or Autotroph =
Makes their own food.

What provides energy for producers?

Consumer or Heterotroph =

Consumes food

Food webs and energy flow

Energy is passed Up a
food chain or Web
from lower to higher
trophic levels

However, generally
only about 10% of
the energy at one
level is available to
the next level.

What do the arrows outside of the food

pyramid represent?

Fig. 1

What do the arrows inside of the food

pyramid represent?

What happens to the available energy as you move

up the energy pyramid?

What happens to the # of organisms as you move up the

energy pyramid?

Food webs and energy flow

Energy in a food web is impacted
by changes that occur at
individual trophic levels

EX: introduction of the Lionfish
in an aquatic ecosystem.

Identify the trophic level
for each species. Use the
terms below to help you
fill in the blanks:

Secondary Consumer
Quaternary Consumer
Tertiary Consumer
Producer
Primary Consumer

Lesson Goals

● Describe trophic levels
● Describe what the arrows represent

on an energy pyramid

● Discuss the transfer of energy

The diagram provided shows a food web that
exists within a forest ecosystem. Which of the
following explains the energy transfer based on
the food web?

A. Energy increases as it transfers from the

rabbit to the grass

B. Energy decreases as it transfers from the

mouse to the hawk

C. Energy increases as it transfers from the

rabbit to the cougar

D. Energy decreases as it transfers from the

bird to the caterpillar

2. Why are producers found at the base of an energy pyramid?

A. Producers contain the largest amount of energy in the ecosystem and

represent the source of energy for all other levels.

B. Producers contain the smallest amount of energy in the ecosystem

because they are consumed by other organisms.

C. Producers contain the smallest amount of energy in the ecosystem

because they require the most resources to produce energy.

D. Producers contain the largest amount of energy in the ecosystem

because they are more likely to consume other organisms, transferring energy to the producers.

2. Based on energy pyramids which level of organisms will have most
available energy?

A. Producers
B. Primary Consumers
C. Secondary Consumers
D. Teritery Consumers