Transcript Energy in an Ecosystem

Energy in an Ecosystem
Energy in an Ecosystem
• Autotrophs vs.
Heterotrophs
Autotrophs
Heterotrophs
Produce own
food
Have to obtain
food
Primary
producers
consumers
Plants
Lion, rabbit, cow
Heterotrophs
• Can be herbivores, carnivores, or
omnivores
• Also include
scavengers and decomposers
-Both are detrivores (eat detritus = dead organic
matter)
Break
down
dead
organic
matter
Models of energy flow
• Food chain: Simple model that shows how
energy flows through an
ecosystem
• Food web: Model representing the many
interconnected food chains and
pathways in which energy flows
through a group of organisms
Food Chain
• Each step in a food chain is called trophic
level
• Autotrophs or dead organic matter makes
the first trophic level in all ecosystems
• Arrows represent energy flow
Producer
Herbivore
Omnivore
Carnivore
Another food chain
Food Web
• More complex
than food chain
because
most organisms feed
on more than one
species
Another Food Web
Activity: Construct a Food Web
Use the following information to construct a
food web in a meadow ecosystem
• Red foxes feed on raccoons, crayfishes,
grasshoppers, red clover, meadow voles,
and gray squirrels
• Red clover is eaten by grasshoppers,
muskrats, red foxes, and meadow voles
• Meadow voles, gray squirrels, and
raccoons all eat parts of the white oak tree
• Crayfishes feed on green algae and
detritus, and they are eaten by muskrats
and red foxes
• Raccoons feed on muskrats, meadow
voles, gray squirrels, and white oak trees
Identify all of the herbivores, carnivores,
omnivores, and detritivores in the food
web
Describe how the muskrats would be
affected if disease kills the white oak trees