Energy Flow Through an
Ecosystem
Food Chains, Food Webs, Energy
Pyramids

•Begins with the SUN
•Photosynthesis
6CO
2
+ 6H
2
O + sunlight & chlorophyll
 C6H
12
O
6
+ 6O
2

• The chemical reaction by which green plants use water and carbon dioxide and light from the sun to make glucose.
• ENERGY is stored in glucose; glucose is stored as starch.

Organisms that can make glucose during photosynthesis are called
AUTOTROPHS
(PRODUCERS)

An organism is …..
• Any independent living thing
• Can be as small as a single celled bacteria
• Or as large as a whale!

Producers Are-
• Producers get their food and energy from the sun.
(PLANTS)
• They are
AUTOTROPHS
• They make their food through a process called photosynthesis.

Producers use most of the energy they make for themselves.

Producers use cellular respiration to supply the energy they need to live.

6O
2
+ C
6
H
12
O
6
--> 6H
2
O + 6CO
2
+ energy
CELLULAR RESPIRATION is the chemical reaction that releases the energy in glucose.

The energy that is not used by producers can be passed on to organisms that cannot make their own energy.

Organisms that cannot make their own energy are called
CONSUMERS. They are
HETEROTROPHS

Consumers
• Consumers need to eat their food to get energy. (ANIMALS)

Types of consumers are
• There are THREE types of Consumers
– Herbivores
– Carnivores
– Omnivores.
• Its still all about what you eat!

Herbivores eat only plants.

Carnivores only eat meat (other animals)

Omnivores eat both meat (animals) and plants.

Stop…Review…Check…
Turn to your partner and tell them the meaning of each word. Also give two examples of each.
• Carnivore:
• Herbivore:
• Omnivore:

Consumers that eat producers to get energy:
• Are first order or primary consumers
• Are herbivores
(plant-eaters)

Most of the energy the primary consumer gets from the producer is used by the consumer.

Some of the energy moves into the atmosphere as heat.

Some energy in the primary consumer is not lost to the atmosphere or used by the consumer itself.
This energy is available for another consumer.

A consumer that eats another consumer for energy:
• Is called a secondary or second order consumer
• May be a carnivore or a herbivore
• May be a predator
• May be a scavenger

Most of the energy the secondary consumer gets from the primary consumer is used by the secondary consumer.

Some of the energy is lost as heat, but some energy is stored and can passed on to another consumer.

A consumer that eats a consumer that already ate a consumer:
• Is called a third order or tertiary consumer
• May be a carnivore or a herbivore
• May be a omnivore
• May be a predator
• May be a scavenger

Consumers that hunt & kill other consumers are called predators.
The animals that are hunted & killed are called prey.

Consumers that eat producers & other consumers
• Are called omnivores
• Omnivores eat plants and animals

Consumers that eat other consumers that have already died are called scavengers.

Decomposers
• Decomposers eat dead things and turn them back into dirt, or soil. YUK!
• Examples:
– Mushrooms
– Worms
– Bugs

What would the world look like without decomposers (bacteria and fungi?

The transfer of energy from sun to producer to primary consumer to secondary consumer to tertiary consumer can be shown in a
FOOD CHAIN .

How they relate
.

Stop…Review…Check…
Turn to your partner and tell them the meaning of each word. Also give two example of each.
• Producers:
• Consumers:
• Decomposers:

On a sheet of note book paper describe the following animals as either a producer, consumer or decomposer. For the consumers, make sure to include if they are a carnivore, herbivore or omnivore. Please use complete sentences! (Ex: A _____ is a ______.)
1. Bear
2. Shark
3. Rabbit
4. Cherry tree
5. Mushroom
6. Human
7. Tulip (flower)
8. Panther
9. Giraffe
10. Worm

Answer Key
1. Consumer / Omnivore
2. Consumer / Carnivore
3. Consumer / Herbivore
4. Producer
5. Decomposer
6. Consumer / Omnivore
7. Producer
8. Consumer / Carnivore
9. Consumer / Herbivore
10. Decomposer

Another way of showing the transfer of energy in an ecosystem is the
ENERGY PYRAMID .

Energy pyramids show
• That the amount of available energy decreases up the food chain
• It takes a large number of producers to support a small number of primary consumers
• It takes a large number of primary consumers to support a small number of secondary consumers

Food Webs:
• Are interconnected food chains
• They show the feeding relationships in an ecosystem
• Sample Food web.docx
• Food Web Example
Game