1. 2.2 Flow of Energy in an
Ecosystem

2. What is the
source of all
energy in this
ecosystem?
What path
does this
energy take
to get to the
hawk?

3. Autotrophs
Also called producers
organisms that use energy from the
sun or energy stored in chemical
compounds to manufacture their own
food
Examples: plants & Chlorophyll-
containing single cell organisms

4. Heterotrophs
also called consumers
organisms that depend on
autotrophs as their source of
nutrients and energy
examples: cow, rabbit, wolf

5. Herbivores
consumers that depend on plants
for their food
examples: grazing, seed-eating,
algae-eating, plant eating animal
Bees, grasshoppers, elephants

6. Carnivores
consumers that kill and eat only
other animals

7. Scavengers
consumers that eat
animals that are
already dead (do not
kill for food)
feed on carrion,
refuse, and similar
dead organisms example:
black vultures

8. Omnivores
consumer that eats both plants
and animals
examples: humans, raccoons,
coyotes, bears

9. Decomposers
break down dead organisms by
releasing digestive enzymes
examples: bacteria & most fungi

10. Food Chain
model scientists use to show how
matter and energy move through an
ecosystem
arrows represent the levels and the
direction the energy is flowing
a food chain consist of three to five
links
energy is “lost” as heat at each link

11. Food
Chain

13. Food Web
a network of interconnected food
chains
expresses all the possible feeding
relationships at each trophic level
in a community
a more natural model

14. Food
Web

17. Ecological pyramid
depicts energy conversions in an
ecosystem
base = producers
higher trophic levels = consumers
source of energy for all ecological
pyramids is energy from the sun;
energy is always being replenished

19. Energy Pyramid
4th trophic 3rd order
level Carnivore heterotrophs
3rd trophic Omnivore 2nd order
level heterotrophs
2nd trophic Herbivores 1st order
level heterotrophs
1st trophic 1st trophic level – autotroph
Producer Auto-
level trophs