Transcript Food Chains and Food Webs

Food Chains and Food
Webs
Energy Flow in Nature
Energy Roles
• An organism’s energy
role in an ecosystem
may be that of a
producer, consumer, or
decomposer.
Producers
• An organism that can make its
own food is a producer.
• Autotroph
• Source of all food in an
ecosystem.
• Capture energy from sunlight
and stores it as food energy.
Consumers
• Consumers are heterotrophs, or
living things that cannot make food
for themselves.
• A food chain contains several kinds
of consumers, each of which
occupies a different trophic level.
• Herbivore, carnivores, omnivores
Consumer Tropic Levels
• Primary consumers eat producers
(herbivores)
• Secondary consumers eat primary
consumers (carnivores)
• Tertiary consumers eat secondary
consumers (carnivores)
• Scavengers are carnivores that feed
on the bodies of dead organisms.
Decomposers
• Help break down wastes
and dead organisms and
return the raw materials
to the environment
• Bacteria and fungi
Food Chains
• Series of events where one
organism eats another and
obtains energy.
• First organism in chain is
the producer.
• The second organism is the
consumer that eats the
producer.
Plankton—Crab—Seal—Orca
This is only one possible chain
in a marine ecosystem.
Come up with an example to fill in
the blocks of a food chain in two
different ecosytems.
Food Webs
• Consists of many
overlapping food chains in
an ecosystem.
• Some organisms may play
more than one role by
changing consumer levels.
What happens in a food web
if one or more of the
organisms disappear?
Which
animals are
carnivores
and
herbivores?
Energy Pyramids
• A diagram that shows the
amount of energy that
moves from one feeding level
to another in a food web.
• Represented in a triangle
with the most energy at the
producer level.
Energy Loss and Use
• 10% of energy transferred to
next higher level.
• 90% of energy is used by
organisms’ life processes.
• Due to energy loss, ecosystem
cannot support many feeding
levels.