2. Flow of Energy (2.2)
State Standard
SB4B. Explain the flow of matter and energy through ecosystems by
Arranging components of a food chain according to energy flow.
Comparing the quantity of energy in the steps of an energy pyramid.

3. Autotrophs are AKA producers.
Chapter 2
Principles of Ecology
2.2 Flow of Energy in an Ecosystem
Energy in an Ecosystem
Autotrophs
Organisms that collect energy from sunlight or inorganic substances to produce food
Autotrophs are AKA producers.
Heterotrophs
Organisms that get their energy requirements by
consuming other organisms
A lynx is a heterotroph.
Heterotrophs are AKA consumers.

4. Photoautotrophs can synthesize food by using light energy.
Chapter 2
Principles of Ecology
2.2 Flow of Energy in an Ecosystem
Types of Autotrophs
Photoautotrophs can synthesize food by using light energy.
Chemoautotrophs can synthesize food by using inorganic chemical substances.

5. Organisms that only eat plants are called herbivores.
Chapter 2
Principles of Ecology
2.2 Flow of Energy in an Ecosystem
Types of Heterotrophs
Organisms that only eat plants are called herbivores.
Ex: cow, rabbit, grasshopper
Carnivores prey on other heterotrophs.
Ex: wolf, lion, lynx
Organisms that eat both plants & animals are called omnivores.
Ex: bear, human, mockingbird

6. Types of Heterotrophs Cont’d
Chapter 2
Principles of Ecology
2.2 Flow of Energy in an Ecosystem
Types of Heterotrophs Cont’d
Detritivores eat fragments of dead matter in the ecosystem, ultimately returning nutrients to the soil, air, & water where they can be recycled.
Ex: worms, millipedes, maggots, vultures
Decomposers break down dead organisms by releasing digestive enzymes.
Ex: bacteria, fungi

7. Types of Heterotrophs Cont’d
Chapter 2
Principles of Ecology
2.2 Flow of Energy in an Ecosystem
Types of Heterotrophs Cont’d
Whenever a heterotroph consumes a producer, it is known as a primary consumer.
A secondary consumer eats a primary consumer.
A heterotroph is a called a tertiary consumer when it eats a secondary consumer.

8. Food chains and food webs model the energy flow through an ecosystem.
Chapter 2
Principles of Ecology
2.2 Flow of Energy in an Ecosystem
Models of Energy Flow
Food chains and food webs model the energy flow through an ecosystem.
Each step in a food chain or food web is called a trophic level.

9. Chapter 2
Principles of Ecology
2.2 Flow of Energy in an Ecosystem
Models of Energy Flow Cont’d
A food chain is a simple model that shows one path of energy flow in an ecosystem.

10. Models of Energy Flow Cont’d
Chapter 2
Principles of Ecology
2.2 Flow of Energy in an Ecosystem
Models of Energy Flow Cont’d
A food web is a complex model representing the many interconnected food chains and pathways in which energy flows through a group of organisms.

11. Chapter 2
Principles of Ecology

15. Chapter 2
Principles of Ecology
2.2 Flow of Energy in an Ecosystem
Ecological Pyramids
Diagrams that can show the relative amounts of energy, biomass (amount of living matter), or numbers of organisms at each trophic level in an ecosystem

16. Chapter 2
Principles of Ecology
Chapter Diagnostic Questions
The act of one organism consuming another organism for food is _______.
predation
parasitism
commensalism
mutualism D C B A
CDQ 1

17. from an autotroph to a heterotroph from a heterotroph to an autotroph
Chapter 2
Principles of Ecology
Chapter Diagnostic Questions
Identify how energy flows through an ecosystem in a typical food chain.
from an autotroph to a heterotroph
from a heterotroph to an autotroph
from a carnivore to an herbivore
from an omnivore to an herbivore D C B A
CDQ 2

18. What type of organism is the foundation of all ecosystems?
Chapter 2
Principles of Ecology
2.2 Formative Questions
What type of organism is the foundation of all ecosystems?
autotroph
herbivore
heterotroph
decomposer D C B A
FQ 4

19. How do detritivores obtain their energy in an ecosystem?
Chapter 2
Principles of Ecology
2.2 Formative Questions
How do detritivores obtain their energy in an ecosystem?
They feed on fragments of dead plants and animals
They feed on organisms by releasing digestive enzymes.
They get energy from inorganic substances to make food.
They use chlorophyll to capture energy from the sun. D C B A
FQ 5

20. Chapter 2
Principles of Ecology
2.2 Formative Questions
Which type of organism exists at all trophic levels except the first trophic level?
carnivores
herbivores
autotrophs
heterotrophs D C B A
FQ 6

21. Why is this mouse classified as an omnivore?
Chapter 2
Principles of Ecology
Standardized Test Practice
Why is this mouse classified as an omnivore?
It is consumed by
snakes.
It consumes
grasshoppers.
It is a third-level
consumer.
It consumes both
grasshoppers and D C B A
STP 4