Energy transfer between
organisms
Energy
• Remember that all
energy starts in the sun.
• Producers can convert
light energy from the
sun into chemical
energy stored in food.
Energy transfer
• Predator/prey
interactions allow for
energy to be transferred
between organisms.
Energy transfer
• This unit, we will look at
3 ways of representing
energy as it flows from
the sun to producers,
and from producers to
consumers.
– Energy Pyramids
– Food Chains
– Food Webs
Energy pyramid
• An energy pyramid
shows how the amount
of energy available
diminishes (gets less) as
it moves from
producers to primary
consumers, then to
secondary consumers,
and on to tertiary
consumers.
Energy pyramid
• The 10% rule says that
only 10% of the energy
at each level moves on
the next level.
• Each level of this
pyramid is called a
trophic level.
• As you move up trophic
levels, less and less of
the sun’s original energy
is available.
Energy pyramid
• What happens to the
other 90% of the energy
at each level?
– Most of it is used by the
organism, or lost as heat.
– Humans radiate about
100 joules of heat per
second. That’s the same
amount of heat that is
radiated from a 100 watt
lightbulb!
Energy pyramid
• So the moral of this
story is…
– It takes a lot of grass to
support one owl. (Even
though owls don’t eat
grass.)
Food Chain
• The flow of energy can
also be shown through
a food chain.
• A food chain shows the
energy flow from
producers through
consumers with a series
of arrows.
Food Chain
• The arrows in a food
chain always go from the
thing that is being eaten
toward the thing that is
eating.
• You can think of the
arrows as meaning “is
eaten by”
• The arrows show the
energy flowing from the
prey toward the predator.
Food chain
• Write a paragraph
describing what is
happening in this food
chain.
Food chain
• Make a food chain using
these organisms
Bluebird
Grasshopper
Grass
Cooper’s
Hawk
Food chain
• Change this food chain
into an energy pyramid.
cabbage
Aphid
Ladybug
bird
Food web
• Multiple food chains
can be combined to
form a food web.
• A food web has arrows
and shows energy flow
just like a food chain
does, but it includes
many more organisms.
Food webs
Food web
• Make a food web by
combining these food
chains
Food Web
Grasshopper
Food web
• Make a food web using
these organisms.
Pinecone
Bird
Leaf
Caterpillar
Squirrel
Hawk
Snake
Wolves in the food chain?
• How might wolves
affect the Yellowstone
ecosystem?
• Wolf video
Humans effect food webs
• How might
humans have
an effect on
this food
web?
Humans effect food webs
• How might
humans
have an
effect on
this food
web?
Humans effect food webs
• How might
humans
have an
effect on
this food
web?
• What is
wrong with
this food
web?
Human influence
• Humans have the ability
to influence their
environment more than
any other organism.
• Most organisms must
change to fit their
environment, or go
extinct, but humans can
change their
environment to fit
them.
Human influence
• With great power comes
great responsibility.
• Remember that carrying
capacity is how much of a
particular organism a
certain environment can
hold.
• Humans have changed
the carrying capacity for
different environments in
many ways.
Human influence
• Humans create
marshland or nesting
boxes for wood ducks,
allowing more wood
ducks to live in a given
area.
• How might this affect:
– Food webs
– Energy flow
Human influence
• Humans do the same
thing for many types of
birds, including the
Purple Martin, which
now relies entirely on
humans for nesting.
• How might this affect:
– Food webs
– Energy flow
Human influence
• Acid rain damages
amphibian eggs and
reduces the number of
frogs.
• How might this affect:
– Food webs
– Energy flow
Human influence
• Cutting down forests
affects many animal
populations including
squirrels.
• How might this affect:
– Food webs
– Energy flow
Human influence
• Suburban sprawl
reduces Mule Deer
winter range, so it
decreases the Mule
Deer population.
• How might this affect:
– Food webs
– Energy flow
Human influence
• Humans become bee
keepers which increases
the number of bees in a
given area.
• How might this affect:
– Food webs
– Energy flow
Human influence
• Hawaii story:
–
–
–
–
Sugar Cane introduced
Rats introduced
Mongoose introduced
Ground dwelling birds
disappear
– Trees that rely upon
ground dwelling birds
disappear
– Humans try to save trees
by cloning them.
Extinction
• An organism that is close
to becoming extinct is
called endangered
• An organism that is
extinct is no longer alive
anywhere on earth.
• 99.99% of all living
things have gone extinct.
• The average species
lifespan is 4 million
years.
Extinction
Tasmanian Tiger 1936
• Here are some things
that have recently gone
extinct
Baiji River Dolphin 2006
Quagga 1883
Passenger Pigeon 1914
Bubal Hartebeast 1923
Extinction?
• Ivory Billed woodpecker – The Grail Bird
Coelocanth
Endangered Species
• Here are some things
that are endangered
African Elephant
Giant Panda
California Condor
Blue Whale
Golden Lion Tamarin
Amur Leopard
Wild Bactrian Camel
Endangered species
razorback sucker
kodachrome Bladderpod
• Here are some endangered
and threatened species that
are found in Utah (21
animals and 22 plants total)
Humpback Chub
Kanab Ambersnail
Southwestern
Willow Flycatcher
Canada Lynx Threatened
Utah prairie dog
Dwarf Bear Poppy
Extinct
• Pick an endangered species,
and write an argumentative
essay about whether that
organism should or should
not be allowed to go
extinct.
• Make sure to relate your
organism to the flow of
energy in the organism’s
ecosystem.
• Make sure you have a claim,
evidence, and a warrant.
http://http://www.endangeredspecie.com//