1. G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page 1G9 S Chapter 1 Lesson 2 –
Flow of Energy in an Ecosystem – p. 41-44 – page 1G9 S Chapter 1 Lesson 2 – Flow of Energy in an
Ecosystem – p. 41-44 – page 1G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page
1G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page 1G9 S Chapter 1 Lesson 2 –
Flow of Energy in an Ecosystem – p. 41-44 – page 1G9 S Chapter 1 Lesson 2 – Flow of Energy in an
Ecosystem – p. 41-44 – page 1
Vocabulary
Autotroph
Heterotroph
Herbivore
Carnivore
Omnivore
Detritivore
Trophic Level
Food Chain
Food Web
Biomass
Outline
Energy in an Ecosystem
Autotrophs
Heterotrophs
Models of Energy Flow
Food Chains
Food Webs
Ecological Pyramids
2. G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page 2G9 S Chapter 1 Lesson 2 –
Flow of Energy in an Ecosystem – p. 41-44 – page 2G9 S Chapter 1 Lesson 2 – Flow of Energy in an
Ecosystem – p. 41-44 – page 2G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page
2G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page 2G9 S Chapter 1 Lesson 2 –
Flow of Energy in an Ecosystem – p. 41-44 – page 2G9 S Chapter 1 Lesson 2 – Flow of Energy in an
Ecosystem – p. 41-44 – page 2
Open Question: What is the original source of the energy we use to live, move, talk, and think?
Energy in an Ecosystem
o All energy in an ecosystem comes from a _________________ and ____________________
throughout the ecosystem.
o Studying the way energy that flows through ecosystem is one way scientists study how
organisms __________________________.
o We also classify organisms by how they ____________________ their energy in an
ecosystem
o Autotrophs
o Heterotrophs
Autotrophs
o All of the green plants and other organisms that produce
their own food in an ecosystem are ___________________ ______________________
called autotrophs.
o An autotroph collects energy from sunlight or ____________________ substances
to produce food.
o Organisms that contain ___________________________ absorb energy during
photosynthesis and use it to convert the inorganic substances, carbon dioxide and water,
to organic molecules.
o In places where sunlight is unavailable, some bacteria use hydrogen
______________ and carbon dioxide to make organic molecules to use as food.
o Autotrophs are the _______________________________ of all ecosystems because they
make energy available for all other organisms in an ecosystem.
3. G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page 3G9 S Chapter 1 Lesson 2 –
Flow of Energy in an Ecosystem – p. 41-44 – page 3G9 S Chapter 1 Lesson 2 – Flow of Energy in an
Ecosystem – p. 41-44 – page 3G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page
3G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page 3G9 S Chapter 1 Lesson 2 –
Flow of Energy in an Ecosystem – p. 41-44 – page 3G9 S Chapter 1 Lesson 2 – Flow of Energy in an
Ecosystem – p. 41-44 – page 3
Heterotrophs
o A heterotroph is an organism that gets its
energy requirements by
_____________________ other
organisms.
o Therefore, all heterotrophs are called _________________________.
o There are four types of heterotrophs:
Herbivores
4. G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page 4G9 S Chapter 1 Lesson 2 –
Flow of Energy in an Ecosystem – p. 41-44 – page 4G9 S Chapter 1 Lesson 2 – Flow of Energy in an
Ecosystem – p. 41-44 – page 4G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page
4G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page 4G9 S Chapter 1 Lesson 2 –
Flow of Energy in an Ecosystem – p. 41-44 – page 4G9 S Chapter 1 Lesson 2 – Flow of Energy in an
Ecosystem – p. 41-44 – page 4
Carnivores
Omnivores
Detritivores
Detritivores
o Detritivores eat pieces of __________________ matter in an ecosystem,
returning ___________________________ to the soil, air, and water where the
nutrients can be reused by organisms.
Worms, millipedes, flies, and slugs
o Decomposer, similar to detritivores, _______________________ dead organisms
by releasing digestive enzymes.
Fungi and bacteria are decomposers
o Decomposers are the primary tool used to breakdown organic compounds and
make nutrients available to ___________________________ for reuse
5. G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page 5G9 S Chapter 1 Lesson 2 –
Flow of Energy in an Ecosystem – p. 41-44 – page 5G9 S Chapter 1 Lesson 2 – Flow of Energy in an
Ecosystem – p. 41-44 – page 5G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page
5G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page 5G9 S Chapter 1 Lesson 2 –
Flow of Energy in an Ecosystem – p. 41-44 – page 5G9 S Chapter 1 Lesson 2 – Flow of Energy in an
Ecosystem – p. 41-44 – page 5
.
Models of Energy Flow
o Ecologists use food chains and food webs to model the _________________________ flow
through an ecosystem.
o Like any model, these are simplified representations of energy flow.
o Each step in a food chain or food web is called a
_______________ ______________.
o _________________________ make up the first
trophic level in all ecosystems.
o Heterotrophs make up the
____________________________ levels.
o Organisms at each trophic level get their energy
from the trophic level ___________________ it,
except for the first trophic level.
Food Chains
o A food chain is a simple model that shows how energy
flows through an ecosystem.
o Arrows represent the ____________________________ energy flow which typically starts
with autotrophs and moves to heterotrophs.
o Each organism in a food chain uses a portion of the energy it obtains from the
organism it eats for cellular processes to build ____________________________ and
tissues.
o The remaining energy is __________________________ into the surrounding environment
as heat and no longer is available to these organisms.
6. G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page 6G9 S Chapter 1 Lesson 2 –
Flow of Energy in an Ecosystem – p. 41-44 – page 6G9 S Chapter 1 Lesson 2 – Flow of Energy in an
Ecosystem – p. 41-44 – page 6G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page
6G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page 6G9 S Chapter 1 Lesson 2 –
Flow of Energy in an Ecosystem – p. 41-44 – page 6G9 S Chapter 1 Lesson 2 – Flow of Energy in an
Ecosystem – p. 41-44 – page 6
Food Webs
o Feeding relationships usually are more complex than a single food chain because
organisms feed on more than one _______________________________.
o A food web is a model representing the many ____________________________ food
chains and pathways in which energy flows through a group of organisms.
7. G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page 7G9 S Chapter 1 Lesson 2 –
Flow of Energy in an Ecosystem – p. 41-44 – page 7G9 S Chapter 1 Lesson 2 – Flow of Energy in an
Ecosystem – p. 41-44 – page 7G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page
7G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page 7G9 S Chapter 1 Lesson 2 –
Flow of Energy in an Ecosystem – p. 41-44 – page 7G9 S Chapter 1 Lesson 2 – Flow of Energy in an
Ecosystem – p. 41-44 – page 7
Ecological Pyramids
Pyramids are models used to represent trophic levels in ecosystems.
o An ecological pyramid is a diagram that can show the relative amounts of
_______________, ____________________, and ____________________ of organisms at
each trophic level in the ecosystem.
o In a pyramid of energy, only ___________ percent of all energy is transferred to the level
above it.
o This occurs because most of the energy contained in the organisms at each level
is consumed by cellular processes or released to the environment as heat.
8. G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page 8G9 S Chapter 1 Lesson 2 –
Flow of Energy in an Ecosystem – p. 41-44 – page 8G9 S Chapter 1 Lesson 2 – Flow of Energy in an
Ecosystem – p. 41-44 – page 8G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page
8G9 S Chapter 1 Lesson 2 – Flow of Energy in an Ecosystem – p. 41-44 – page 8G9 S Chapter 1 Lesson 2 –
Flow of Energy in an Ecosystem – p. 41-44 – page 8G9 S Chapter 1 Lesson 2 – Flow of Energy in an
Ecosystem – p. 41-44 – page 8
o Usually, the amount of biomass – the _________ mass of living matter at each
trophic level – ________________________________ at each trophic level.
o As shown in the pyramid of numbers, the relative ____________________ of
organisms at each trophic level also decreases because there is less energy
available to support organism.