Download Ch. 23

Ch. 23 Ecosystems and
Biomes
Sect. 1 Energy Flow in Ecosystems
Each organism has a role in the movement of
energy through the ecosystem.
• Producer- an organism that can make its own food
• Consumer-an organism that obtains energy by feeding on other
organisms
• Decomposer- an organism that breaks down dead organisms and
returns the raw materials back to the environment.
Producers are plants,algae, and some bacteria that can take
energy from the sun and carry out photosynthesis. Some
bacteria can use chemicals from the environment and produce
food through chemosynthesis.
Consumers are classified by what they eat.
• Herbivores- eat only plants
• Carnivores- eat only animals
• Omivores-eat both
• Scavengers-feed on dead bodies
Herbivores
Carnivores
Omnivore
Decomposers
Food Chain
Food Web
The arrow is pointing to the direction that
receives the energy
Energy Pyramid
In general, only 10% of the energy at one level of a
food web is transferred to the next, higher level.
The other 90% of the energy is used by the
organism for living.
• Since 90% is not available, there is not enough energy to support
many feeding levels. That is why it looks like a pyramid. The largest
amount of available energy is at the producer (bottom) level.