Energy Flow
SC.912.L.17.9
Use a food web to
identify and distinguish
producers, consumers,
and decomposers.
Explain the pathway of
energy transfer through
trophic levels and the
reduction of available
energy at successive
trophic levels
Source: http://www.bigelow.org/bacteria/land.jpg
What do I need to know?
 how to use a food web to identify
producers, consumers, and
decomposers
 the pathway of energy transfer
through trophic levels and the
reduction of available energy at
successive trophic levels
 how matter and energy move
through the water and carbon
cycles
Food Chains vs.
Food Webs
Food chains are
linked together into
food webs
 Who eats whom?
 What type of
organism do they
both begin with?
 How does energy
flow from the sun
to producer to the
consumers?
Source:http://www.majordifferences
.com/2013/02/difference-betweenfood-chain-andfood.html#.U7tjc7fjiP8
Food Webs
Video Guiding Questions:
1. Can you identify a food
chain in the food web?
2. What is the difference
between a primary and
a secondary
consumer?
3. What happens if an
organism is removed
from a food web?
Video: http://www.odysseyearth.com/videos/the-food-web/
The Food Chain Game
Energy Transfer
 energy does not cycle
through ecosystems
but instead enters
ecosystems and is
used up within
ecosystems
 energy is not “lost”
from ecosystems but
primarily converted to
waste heat
Source:http://www.tutorvista.com/co
ntent/biology/biologyiv/ecosystem/ten-percent-law.php
Energy Transfer: Energy Pyramids
The 10% Rule
Video Guiding Questions:
1. What is the 10% rule?
2. If 90% of energy is
lost within each level,
where does it go?
Trophic Levels
 greek (trophē)
referring to food or
feeding
 position that an
organism occupies in
a food chain
 can be represented by
numbers, starting at
level 1 with producers
Guess the Trophic Level?
Trophic Level 2
Trophic Level 4
Trophic Level 3
Trophic Level 1
Vegetarians or Meat-eaters?
How many people can the Earth support?
 If we are meat-eaters?
 If we are vegetarians?
more people can
live on Earth
fewer people can
live on Earth
Cycling of Energy & Matter
 solid blue lines trace
matter cycles
and the broken red
lines trace energy
flow
 energy flows through
ecosystems, while
matter cycles within
them
Source:
http://science.kennesaw.edu/~jdirnber/Bio2108/Lectu
re/LecEcology/54-01-EcosystemDynamics-AL.gif
Ecosystem Inputs
energy flows
constant
input
of energy
through
nutrients cycle
Matter
Don’t
forget
cannot
thecreated
be
laws of or
Physics!
destroyed
biosphere
nutrients
can only
cycle
inputs
 energy
 nutrients
Biogeochemical Cycles

matter moves
through these
cycles, it is never
created or destroyed
– just changed

involves biological,
geological, and
chemical processes
Source:http://pubs.usgs.gov/pp/p13
86a/gallery1-fig01.html
The Water Cycle
 water moves
continuously
between the oceans,
atmosphere and the
land – sometimes
outside living
organisms and
sometimes inside
them
Source:http://ga.water.usgs.gov/ed
u/watercycle.html
Water Cycle:
Main Processes
 precipitation: moisture
that falls to the ground
(rain, snow, sleet, hail)
 evaporation: changing
from liquid to gas (water
to water vapor)
 transpiration: plants give
off water vapor from their
leaves to the air
 condensation: changing
from gas to a liquid
Source: http://www.biofuelswatch.com/stepsof-the-water-cycle/
Water Cycle: The Basics
Reservoir
oceans, air (as water vapor),
groundwater, lakes and glaciers;
evaporation, wind and precipitation
(rain) move water from oceans to
land
Assimilation
plants absorb water from the ground,
animals drink water or eat other
organisms which are composed
mostly of water
Release
plants transpire, animals breathe and
expel liquid wastes
Water Cycle Animation
http://earthguide.ucsd.edu/earthguide/diagrams/watercycle/
The Carbon Cycle
 every organic
molecule contains
the element carbon
 carbon is required
for building organic
compounds
 carbon and oxygen
form carbon
dioxide gas (CO2)
Source:http://commons.wikimedia.o
rg/wiki/File%3ACarbon-cycle-full.jpg
Where’s the Carbon?
Carbon Cycle: The Basics
Reservoir
atmosphere (as CO2), fossil fuels (oil,
coal), durable organic materials (for
example: cellulose)
Assimilation
plants use CO2 in photosynthesis;
animals consume plants
Release
plants and animals release CO2
through respiration and
decomposition; CO2 is released as
wood and fossil fuels are burned
Carbon Cycle Game
https://www.windows2universe.org/earth/climate/carbon_cycle.html
Show What You Know
A team of ecologists observed feeding patterns of
several populations in the desert. The energy
pyramid shown below depicts the feeding patterns
the ecologists observed.
Show What You Know
Which of the following best explains the difference in
the amount of available energy in the trophic levels of
the desert ecosystem?
A. There is less energy available in the producers
because their tissues are less dense than those at
higher trophic levels.
B. There is more energy available in the second
trophic level because less energy is needed for
hunting compared to the higher trophic levels.
C. There is more available energy in the birds of prey
because they have greater muscle mass for storing
energy than organisms in lower trophic levels
have.
D. There is less available energy in the fourth trophic
level because of the loss of energy through
metabolism in each of the lower trophic levels.
Show What You Know
The table below contains information
about animal diets.
Animals
Diet
Snakes
Squirrels, chipmunks,
gophers and mice
Hawks and owls
Rodents and reptiles
Rodents
Seeds, nuts, root, grass
leaves and flowers
Which energy pyramid best represents the
data in the table??
Show What You Know
Show What You Know
Which model correctly shows energy
flow in a food chain?
A. plants  insects  salmon  bears
B. insects  plants  bears  salmon
C. bears  salmon  insects  plants
D. salmon  bears  plants  insects
Show What You Know
Which diagram correctly shows the
direction of energy flow through a food
web?
Show What You Know
Part of an everglades food web is diagrammed below.
Which of the following will most likely result if all of the
primary consumers are removed from this ecosystem?
A. Raccoons will become herbivores.
B. American alligator populations will decrease.
C. Grass carp will consume soil bacteria.
D. Bladderwort and Butterfly orchid populations will
decrease
Show What You Know
A student set up a terrarium, watered the
soil, and covered the terrarium tightly with a
lid. The next day, the student observed
water droplets on the inside of the lid.
The droplets provide evidence that which of
the following steps of the water cycle had
occurred in the terrarium?
A.
B.
C.
D.
runoff and evaporation
precipitation and runoff
evaporation and condensation
condensation and precipitation
Show What You Know
Use the diagram of the water cycle to
answer the following question.
Show What You Know
Which terms match the number order of
the processes shown in the water cycle?
1
A
B
C
D
vaporation
condensation
precipitation
evaporation
2
precipitation
evaporation
condensation
condensation
3
condensation
precipitation
evaporation
precipitation
Show What You Know
Which process is not essential for the
water cycle to occur?
A.
B.
C.
D.
water vapor condensing
energy being transferred from the Sun
liquid water evaporating
oxygen being dissolved in water
Show What You Know
The natural cycling of oxygen between
organisms and their environment is
most directly accomplished through
which of the following pairs of
processes?
A. fermentation and oxidation
B. transpiration and evaporation
C. precipitation and condensation
D. photosynthesis and respiration
Show What You Know
The diagram below shows part of the
carbon cycle.
Show What You Know
If many trees are removed from a forest
by logging, what is the most immediate
effect on the carbon cycle in that forest?
A.
B.
C.
D.
increased rates of decomposition
decreased use of atmospheric CO2
decreased combustion of fossil fuels
increased production of organic
compounds
Show What You Know
The diagram shows the flow of carbon in a terrestrial
ecosystem.
Which will most likely happen if the decomposers are
removed from the carbon cycle?
A. The amount of carbon dioxide in the atmosphere will
increase.
B. The amount of carbon dioxide in the atmosphere will
decrease.
C. The amount of carbon dioxide used by producers will
increase.
D. The amount of carbon dioxide needed by consumers will
decrease.