Energy Flow in the Biosphere
Chapter 2
Section 2.1 Energy Transfer & Food
Webs
• Trophic Level- a category of living things
defined by ___ __ _____ ___ ______; the first
trophic level contains __________, and each
higher level contains ____________
• Autotroph-an organism that uses the ____
______ and raw materials to make it’s own
food. AKA a ________
• Heterotroph-an organism that feeds on other
_________ to gain energy
• First Trophic Level
– _________________________________________________
_________________________________________________
___________
– These organisms are known as autotrophs (____-_______)
– Examples include
• _____________
• ______________
• ___________________

Second Trophic Level
Contains organisms that feed on _____________
 These organisms are referred to as __________ consumers
 ________ _____________- are organisms that rely directly on
autotrophs for their source of energy
 Examples

_________________
 _________________
 _________________

• Third Trophic Level
– The 3rd trophic level is comprised of
___________ ____________
– Secondary Consumers are organisms that
rely on ____________ ___________ for its
main source of energy.
– Examples
• _________
• _________
• _________
• Food Chain
Draw diagram of food chain
– Visual aid to show
_____-___-_____
sequence of ____ eats
______ in an ecosystem
• ______ _____
– An ________________
representation of the
feeding
______________
among organisms in an
ecosystem
Checkpoint
• Working alone, students will complete the
provided quiz.
• This is a tool to check your understanding
How Did You Do?
Photosynthesis
• Photosynthesis is the process by which ______
_______ and some other organisms use
________ _______, carbon dioxide and _______
to produce _________________.
• Captures solar energy and stores it in the
____________ bonds of __________ (C6H12O6)
– CO2(g) + H2O(l) LIGHT ENERGY
CCHLOROPHYLL
6H12O6(s) + O2(g)
• Photosynthesis provides the ________ required
to sustain entire ______________
Overview of Respiration
• All organisms undergo ___________
___________ to use the ________ in their
food
• Breaks down _________, releasing the
energy stored it its ______
• Part of this energy is used to fuel ____
___________, and some is released as
_________ ________
• Maintain a balance of ____ and ____ on earth
• Plants __________ O2 & __________ during
photosynthesis
• All organisms produce ______ & ______ during
cellular ___________
• Plants carry out both processes, however, they
produce __ times the amount of O2 by
_______________ than they use up in
___________ ______________
Photosynthesis
Respiration
Occurs at all times in cells
Requires energy (light) to make
glucose
Complex substances (glucose) are
broken down into simpler ones
Carbon dioxide and water are the raw
materials
Oxygen is given out
Chemosynthesis
• Chemosynthesis is the process by which nonphotosynthetic organisms _______________
______________ chemicals to organic compounds
____________ solar energy
• Chemoautotrophs are organisms that _____________
organic compounds from inorganic chemicals without
using __________
– List some of the compounds they can produce energy from
• ___________________
• ___________________
• ___________________
Limits on Energy Transfer
• Energy transfer in the
food chain is
____________
• Every time energy is
_______________
between organisms in
an ecosystem, the
amount of energy
available to the next
level is ___________.
• Less energy is available
to ___________
consumers than to
___________ consumers
Producers, like
the spruce, use
________
energy to make
glucose. The
plant uses most
of that energy
to _____ and
______.
The deer relies on the
______________ _______
produced by the spruce buds
to sustain it. Some of the
energy is eliminated as
________ some is lost as
________, some fuels the
deer’s cells via cellular
respiration. Only ____% of
the energy in the buds is
transferred to the deer.
The wolf loses
some of the energy
in its meal during
______________
and body
maintenance. Only
about ____% of
the energy in the
wolf’s meal is
transferred to the
wolf
Ecological Pyramids Show
• That the amount of
available energy
____________ down
the food chain
• It takes a large
number of
______________ to
support a small
number of
_____________
consumers
• It takes a large
number of primary
consumers to support
a ______ number of
______________
consumers
Law of Thermodynamics
• Thermodynamics is the study of _________
_________________
• 1st Law
• 2nd Law
_____% to
decomposers
16.2% to
__________
consumer
______% of
_____________
energy
______% of energy lost
by ________________
Your Job
• Section 2.1 Questions
– Pg. 27, #’s 1-8
Section 2.2 Scientific Models
Scientific Models Are
• ____________ descriptions or ___________ that help
us visualize something that cannot be ____________
___________
• ___________________________________________
• Mathematical models (equations) help them
understand biological observations
1. Make an ___________ and develop an __________ based
on indirect data
2. __________ the prediction implied by the equation
3. Compare the prediction with future or past events, gather
supporting __________. If model doesn’t support a
situation, model is __________
Believed that ________ could run at speeds greater
than _________km/h
Using ____________________ _______, they
determined falling at that speed would create forces
on the chest equal to a 36 tonne mass-crushing it’s
ribcage and snapping its neck
Scientists now believe T. rex likely didn’t run any faster
than 15 km/h
Pyramid of
Numbers
• Count the __________
of __________ at each
trophic level in an
ecosystem
• Usually looks like a
pyramid
• Depending on the
physical size of the
members of the food
chain, it may not look
like a pyramid
I falcon
3 robins
50 oak, maple trees
Pyramid of Biomass
9 g falcon
45 g duck
• Biomass- is the total
dry mass of all the
living material in an
ecosystem
• Measures stored
energy content
• Very rare that it
doesn’t produce a
pyramid
976 g moss, algae
Pyramid of Energy
88 kJ
1600 kJ
14078 kJ
8696 kJ
• Only a fraction of the
energy passes from one
level to the next
• This fraction is roughly
10%
Do on Your Own
• Do Practice question # 3
on pg. 32
Practice
• Complete Section 2.2 Questions, pg. 34,
– #’s 3 (ignore drawing pyramids), 4, 6, 7
• Complete Chapter 2 Review, pgs. 38-39,
– #’s 1-4, 6-15, 16 (omit sketches), 17-20, 23, 24 (omit
a & e), 26