Aquatic and Terrestrial
Food Webs
Warm-Up:
 Update your Table of Contents for today
 Write your homework – get it stamped!
Get your predator-prey graphs out to be checked!
ANSWER ON PAGE 6:
What is the difference between a food chain and a food
web?
2) How are terrestrial (land) food webs and aquatic (water)
food webs connected? Can you give an example?
1)
Date
Session
#
4/20 &
4/21
3
Activity
Page
#
Relationships in an Ecosystem Part 2
6
Food Chain/Food Web Practice
7
WHO’S EATIN’ WHO?
 Food chain– shows how each living
organism in an ecosystem are linked by
what they eat
Food web –
complex
network of
food chains in
an ecosystem
WHO’S EATIN’ WHO?
What are the 3
main components
of a food web?
 Producers
 Consumers
 Decomposers
THE PRODUCERS
 Producers are the plants.
 Plants are the base of every food
chain. All of their energy comes
from the sun.
 They are called producers
because they are able to produce
their own food through
photosynthesis!
 What are organisms that can
make their own food called?
autotrophs
THE CONSUMERS
 Consumers are the next link in the
food chain and they must consume
food to survive. Animals that
cannot make their own food are
called heterotrophs
There are three levels of
consumers.
1) Primary Consumer - Eat the
producers
2) Secondary Consumer - Eat the
primary consumers
3) Tertiary Consumer - Eat the
primary or secondary consumers
PRIMARY CONSUMERS
 These are the plant
eaters of the chain.
 What is another
word for plant eater?
herbivore
 What are some
examples?
SECONDARY CONSUMERS
 Secondary consumers
typically eat the
primary consumers,
but they can eat both
plants and animals.
 What word describes
this?
Omnivores
 What are some
examples?
TERTIARY CONSUMERS
 They eat eat the secondary
and primary consumers.
 Animals that ONLY eat meat
are called…?
carnivores
 This group of consumers are
also commonly referred to as…?
Top predators
DECOMPOSERS
 Decomposers break
down dead organisms
so the nutrients can be
returned to the soil.
 Which type of “vore”
are they?
Detritivore
BIG IDEA #1
 Food chains & webs
transfer energy within
an ecosystem…energy
FLOWS from one level
to the next!
REVIEW:
 What is the initial
source of all of the
energy in a food
chain?
 Through which
process is this energy
created?
Trophic Levels
 This is why each level
of the energy pyramid
is referred to as a
trophic level.
 Troph = energy
Example
 If the phytoplankton
starts off with 900,000
kcal, how much energy
will each of the other
levels have?
 Small crustaceans =
 Herring =
 Mackeral =
 Shark =
Energy Pyramid
 Represents the energy
available at each
trophic level.
Number Pyramid
 Represents the number of
individual organisms
available for energy at each
trophic level.
 What could you use this
information for?
Biomass Pyramid
 Represents the total
estimated mass of living
organism matter at each
trophic level. Sometimes
they can be inverted.
 What could you use
this information for?
Food Chain/Food Web Practice:
Into the Forest
ROLES:
Reader/Leader – Reads ALL of the directions BEFORE you
start the game so you know what you are in for &
ensures the game is being played correctly.
Supply Manager – retrieves & returns game. Counts the
cards to make sure you have the same amount before
and after! (41) Deals the cards each round.
Score Keeper – accurately records the score for each group
member on the score card after each round!
Time Keeper – times each 10 minute round & helps group
members tally their points after each round (someone
with a timer and calculator on their phone)
Homework
EOG Review Booklet Checkpoint #1:
A-day: Friday
B-day: Thursday
You must have AT LEAST one full unit
complete!
Warm-Up:
 Update your Table of Contents for today!
 Write a homework reminder – get it stamped!
 Complete the Create Your Own Food Web
Warm-Up & answer the 2 questions below it.
Date
Session
#
4/22 &
4/23
4
Activity
Page
#
What Affects an Ecosystem?
8
Biogeochemical Cycles
9
What Affects the Food Chain?
Turn & Talk:
- Talk to your table partner
about things that affect
the food chain…list them
on the top of your note guide!
- How can changes in the food
chain/web affect the ecosystem
as a whole?
How do Organisms Affect an
Ecosystem?
 https://vimeo.com/86466357
 What is a “trophic cascade?”
 Describe the chain reaction caused by
introducing wolves into Yellowstone.
 Other than transforming the ecosystem,
what else did the wolves actually transform?
How Does Pollution Affect an
Ecosystem?
Example: A factory dumps Mercury into a lake.
The Mercury settles down to the bottom of the
lake where it sinks into the mud.
 Which organisms are affected first?
 What happens when those organisms get
eaten?
Pollution in the Food Chain
 Bioaccumulation – Describes how a pollutant
enters the food chain and begins to
“accumulate” within that organism
 Biomagnification – Describes how the
pollutant increases or “magnifies” as it moves
up the food chain
How do Biogeochemical Cycles
Affect the Ecosystem?
BIG IDEA
#2
 Matter cycles
through an
ecosystem
repeating the
same steps over
and over!
 Carbon Cycle
 Nitrogen Cycle
Biogeochemical Cycles
 Natural cycles such Bio = Life
as the water cycle,
carbon cycle,
nitrogen cycle are
referred to as
biogeochemical
cycles.
Geo = Earth
Chemical = of
or pertaining to
chemistry
The Carbon Cycle - Simplified




START WITH CARBON DIOXIDE FROM THE AIR
Photosynthesis - Plants perform photosynthesis and
create oxygen
Respiration (breathing) – Animals breathing in oxygen,
breathing out carbon dioxide
Decay - When plants and animals die they decay and turn
into fossil fuels.
Combustion (burning) – Burning fossil fuels; released
carbon dioxide into atmosphere
Study Jams Video on the Carbon Cycle
Steps of the Carbon Cycle – In Depth




START WITH CARBON DIOXIDE FROM THE AIR
Photosynthesis- Plants use photosynthesis to make
energy by taking carbon dioxide (CO2), sunlight, and water
and turning it into oxygen and sugar.
Respiration (breathing) - Every time you, or animals,
breathe you turn oxygen into carbon dioxide.
Decay - When plants and animals die they decay. When
this happens, the carbon in their body will either be
released into the atmosphere or stored in ground as fossil
fuels.
Combustion (burning) - When plants, trees, or fossil fuels
are burned, carbon is released into the atmosphere again.
Steps of the Nitrogen Cycle - Simplified
START WITH NITROGEN FROM THE AIR
 Fixation – nitrogen is turned into ammonia
 Nitrification – ammonia is turned into nitrates
 Assimilation– plants absorb nitrates; animals &
humans eat the plants and use the “fixed” nitrogen
 Ammonification- plant or animal dies, nitrates are
broken back into ammonia
 Denitrification – ammonia is broken back into
nitrogen and is released back into the air
Study Jams Video on the Nitrogen Cycle
Steps of the Nitrogen Cycle – In Depth
START WITH NITROGEN FROM THE AIR
 Fixation–Bacteria combines the nitrogen with hydrogen to




make ammonia (NH3), “fixing it” so that it can start to
become usable by plants.
Nitrification–A different bacteria take the ammonia and
combine it with oxygen make nitrates.Nitrates are what the
plants can actually absorb.
Assimilation– The plantsabsorb nitrates from the soil into
their roots to use in different processes. Animals & people eat
the plants.
Ammonification- When a plant or animal dies, it
decomposes back into the soil and a 3rd type of bacteria
breaks the nitrates back down into ammonia so it can reenter the nitrogen cycle by going right back into the
nitrification step.
Denitrification–There is a 4th type of bacteria that steal the
oxygen leaving only the extra nitrogen and release it back
into the air.
What are the Steps of the
Nitrogen cycle?
Play-Doh Nitrogen Cycle
• Use your notes to
build one giant cycle
with your table partner
on the whiteboard.
• Talk about it while
you are building it, and
quiz each other by
explaining the whole
cycle after you finish
building it
• Take a picture of your
creation to study from
later.
What are the Steps of the
Carbon Cycle?
Play-Doh Carbon Cycle
• Build the Carbon
Cycle only if you
have finished the
Nitrogen Cycle and
feel comfortable
with it!
• Take a picture
when you are
done!
REVIEW
Go to www.studyjams.com
Click on Science, then choose
Ecosystems
Watch the relevant videos you
need the most to start
reviewing for your test next
week!
HOMEWORK
 Ecology Test
 A-day: Thursday, 4/30
 B-day: Friday, 5/1
EOG Checkpoint #2
 A-day: Thursday, 4/30
 B-day: Friday, 5/1
Extra Credit: Biogeochemical
Cylces WebQuest – 10 points
 Complete the Biogeochemical Cycles WebQuest
and turn it in for 10 extra credit points…due by the
end of the quarter!