Energy Flow in an Ecosystem Lesson

1

Energy Flow in
an Ecosystem

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How Ecosystems Work

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2

3

Energy Flow

• Energy in an ecosystem originally

comes from the sun and flows
from producers to consumers
–Producers (make food)
–Consumers (use food by eating

producers or other consumers)

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Multiple Choice

Where does Energy originate in an ecosystem?

• From the moon

• From underground geothermal sources
• From ocean currents

• From the sun

Multiple Choice

What is the purpose of Producers during the Energy flow?

• To absorb energy from consumers
• To consume food

• To break down waste materials
• To make food

4

Producers

• Sunlight-source of

energy for most life
on earth.

• Producers contain

chlorophyll & use
energy directly from
the sun

• Also called autotrophs

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5

Autotrophs

• Autotroph-organism that can

produce its own food (Ex. plants,
algae, some protists, & some
bacteria

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6

Niche of a Producer

• Captures energy and transforms

it into organic, stored energy
(glucose)

a. photoautotrophs use light energy

(e.g. photosynthesis in plants)

b. chemoautotrophs use chemical

energy (e.g. cyanobacteria)

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7

Chemoautotrophs

• Capture energy from

the bonds of inorganic
molecules such as
Hydrogen Sulfide

• Process is called

Chemosynthesis

• Often occurs in deep

sea vents or gut of
animals

Called a Black

smoker (thermal

vent)
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Multiple Choice

What is an autotroph?

• An autotroph is an organism that can produce its own food.
• An autotroph is an organism that cannot produce its own food.
• An autotroph is an organism that only eats meat.
• An autotroph is an organism that relies on other organisms for food.

8

Tube Worms living in Black

Smoker

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9

Consumers

Heterotrophs that eat other

organisms to obtain energy.

(e.g. animals)

a. Herbivores

–only plants

b. Carnivores

–Only animals

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10

Consumers

c. Omnivores (Humans)

– plants & animals

d. Detritivores (Scavengers)

– Dead plant & animal remains

(buzzards)

e. Decomposers

– fungi & bacteria

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Multiple Choice

What is a heterotroph?

• An organism that can produce its own food through photosynthesis
• An organism that only consumes meat for energy
• An organism that lives in extreme environments
• An organism that cannot produce its own food and relies on consuming other organisms for energy.

Multiple Choice

What is a carnivore?

• A creature that feeds on both plants and meat.
• An animal that only eats plants.
• An organism that lives in water.
• An animal that primarily eats meat.

Multiple Choice

What is an omnivore?

• An omnivore is an animal that eats both plants and other animals.
• An omnivore is an animal that eats sunlight.
• An omnivore is an animal that eats rocks and minerals.
• An omnivore is an animal that eats only plants.

11

Feeding Relationships

Energy flows in one

direction

from producers to

different levels of
consumers

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12

Feeding Relationships

• Food Chain

–Simple energy path through an

ecosystem

• Food Web

–Realistic path through an

ecosystem made of many food
chains

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13

Food Chain

Producer

Primary
Consumer

Secondary
Consumer

Tertiary
consumer

Quaternary
Consumer

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14

Name the Producer, Consumers

& Decomposers in this food

chain:

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15

Food Web

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16

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Multiple Choice

What is the difference between a food chain and a food web?

• A food chain is circular, while a food web is linear.
• A food chain involves only producers, while a food web includes consumers.
• A food chain represents energy flow, while a food web shows predator-prey relationships.
• A food chain is linear, while a food web is interconnected.

17

Trophic Levels

Each level in A food chain or food

web is a trophic level.

a. Producers

–Always first (1st) trophic level

(how energy enters the system)

• Herbivores

–Second (2nd) trophic Level

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Trophic Levels

c.Carnivores/Omnivores

–Remaining trophic levels

Each level depends on the

one below it for energy.

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19

Ecological Pyramids

Amounts of energy or matter at

each trophic level

May be:
• Energy Pyramid
• Biomass Pyramid
• Pyramid of Numbers

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20

Energy Pyramid

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21

Biomass Pyramid

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22

Pyramid of Numbers

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Multiple Choice

How much energy is transferred as we move up an energy pyramid?

• 10%
• 75%
• 50%
• 25%