1. Chapter 2 Principles of Ecology
Section 1: Organisms and Their Relationships
Section 2: Flow of Energy in an Ecosystem
Section 3: Cycling of Matter

2. 2.2 Flow of Energy in an Ecosystem
NUTRITION
The ultimate source of energy is the SUN, which supplies the energy that fuels life.

3. Energy in an Ecosystem (Types of Niches)
Chapter 2
Principles of Ecology
2.2 Flow of Energy in an Ecosystem
Energy in an Ecosystem (Types of Niches)
The Producers
Autotrophs
- Organism that collects energy from sunlight or inorganic substances to produce food
- Plant’s use the sun’s energy to manufacture food in a process called photosynthesis

4. Energy in an Ecosystem (Types of Niches)
Chapter 2
Principles of Ecology
2.2 Flow of Energy in an Ecosystem
Energy in an Ecosystem (Types of Niches)
The Consumers
- Heterotrophs
Organism that gets it energy requirements by consuming other organisms
A lynx is a heterotroph.

5. 2.2 Flow of Energy in an Ecosystem
Chapter 2
2.2 Flow of Energy in an Ecosystem
Primary Consumers: an organism that gets its energy from producers (plants); usually called herbivores
Secondary Consumers: a consumer that gets its energy from other consumers; usually called carnivores
Types of consumers
Herbivores: only eats plants
Carnivores: prey on other heterotrophs
Omnivores: eat both plants and animals
Scavengers: animals that feed on animals that have already died (ex: vultures, ants, beetles)
Decomposers: organisms that break down and absorb nutrients from dead organisms (ex: fungi, bacteria)

6. Detritivores eat fragments of dead matter in an
Chapter 2
Principles of Ecology
2.2 Flow of Energy in an Ecosystem
ecosystem, and
return nutrients
to the soil, air,
and water where
the nutrients can
be reused by
organisms.
Detritivores eat fragments of dead matter in an
Fungus

7. Detritivores 2.2 Flow of Energy in an Ecosystem Chapter 2
Principles of Ecology
2.2 Flow of Energy in an Ecosystem
Detritivores

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. Food Chains 2.2 Flow of Energy in an Ecosystem
Chapter 2
Principles of Ecology
2.2 Flow of Energy in an Ecosystem
Food Chains
A food chain is a simple model that shows how energy flows through an ecosystem.
Arrows indicate the direction in which energy is transferred
Usually 3-5 links; energy is lost in every transfer
Energy is lost to the environment as HEAT

10. Food Chains 2.2 Flow of Energy in an Ecosystem Chapter 2
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2.2 Flow of Energy in an Ecosystem
Food Chains

11. Chapter 2
Principles of Ecology
2.2 Flow of Energy in an Ecosystem
Food Webs
A food web is a model representing the many interconnected food chains and pathways in which energy flows through a group of organisms.

12. Food Webs 2.2 Flow of Energy in an Ecosystem Chapter 2
Principles of Ecology
2.2 Flow of Energy in an Ecosystem
Food Webs

14. Chapter 2
Principles of Ecology
2.2 Flow of Energy in an Ecosystem
Ecological Pyramids
A diagram that can show the relative amounts of energy, biomass, or numbers of organisms at each trophic level in an organism