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13.3 Energy in Ecosystems
KEY CONCEPT
Life in an ecosystem requires a source of
energy.
13.3 Energy in Ecosystems
All organisms must have a source
of energy in order to survive.
However, not all organisms obtain
their energy by eating other
organisms.
13.3 Energy in Ecosystems
Producers provide energy for other organisms in an
ecosystem.
Producers get their energy from non-living
resources and are also called autotrophs because
they make their own food.
Auto= self
13.3 Energy in Ecosystems
Almost all producers obtain energy from sunlight.
• Most producers use sunlight (photosynthesis) as their
energy source.
• Chemosynthesis in prokaryote producers use chemicals as
an energy source instead of sunlight.
Chemosynthetic bacteria thrive
in many of Yellowstone National
Park’s hydrothermal pools
carbon dioxide + water +
hydrogen sulfide + oxygen
sugar + sulfuric acid
13.3 Energy in Ecosystems
Consumers are organisms that get their
energy by eating other living or once-living
resources. They are also called heterotrophs
because they feed off of different things.
Hetero=different
13.3 Energy in Ecosystems
ASSESSMENT
1. If a spider is a keystone species in an ecosystem, what
would happen if we removed all of the spiders?
2. How does the stability of an ecosystem depend on its
producers?
4. Could producers survive without consumers?
13.3 Energy in Ecosystems
1. If a spider is a keystone species in an ecosystem, what would happen if we
removed all of the spiders?
Flys or other insects would take over. They might eat all of the plants,
which would, in turn, leave no food for the herbavores that eat those plants.
When those animals die, their will be no food for the carnivores. The whole
ecosystem would collapse.
2. How does the stability of an ecosystem depend on its producers?
Producers bring energy into an ecosystem.
3. Could producers survive without consumers?
Producers do not require consumers to survive. Consumers on the other
hand, cannot live without producers.