Name __________________________________________ Date _____________ Hour ______
Outcome 3 – Ecology Unit
Laws of Conservation:
Law of Conservation of Matter:
In any ordinary physical or chemical change, matter is neither created nor destroyed, only
transformed from one form to another
Law of Conservation of Energy:
In any ordinary physical or chemical change, energy is neither created nor destroyed, only
transformed from one form to another.
(Also known as the 1st Law of Thermodynamics)
2nd Law of Thermodynamics: When energy is ____changed_______ from one form to
another, …
“Nothing is ever 100% efficient”
nd
The 2 Law of Thermodynamics is due to
Entropy – the tendency toward randomness.
(Energy does not want to be contained.)
Flow of Energy through Ecosystems:
Food Chain = A simple diagram of one string of feeding relationships in an ecosystem,
showing the direction of the transfer of energy in that system.
SUN
Grass
Rabbit
Fox
Wolf
Bacteria
Nutrient-rich Soil
A food chain will always start with the sun’s energy flowing to the autotrophs (producers), then
herbivores, then one or more carnivores. Decomposers will eventually consume all organisms.
Producers = Organisms that make their own food from inorganic molecules and energy.

For example: Plants, blue green algae, phytoplankton

Most accomplish energy building through ________photosynthesis____________:
H2O + Sunlight + CO2  Sugar + O2
Consumers = Organisms that cannot make own food.

Obtain energy by eating other organisms through a process called ______Cellular__
_________Respiration__________:
Sugar + O2  CO2 + H2O + ENERGY
•
Decomposers = Bacteria and fungi that break down organic material
Decomposers are essential to ecosystem health because they
recycle nutrients back for producers to reuse.
Food Web - a group of food chains showing all of the feeding relationships in
an ecosystem.
Man
Sun
Fox
Wolf
Sheep
Rabbit
Mice
Deer
Bacteria
Grass
Flowers
Nutrient-Rich Soil
2
Carrots
Example Food Web Work:
Tips for Creating Food Webs – What do all food webs need?
 Original source of energy (This is usually the sun!)
 Producers
 Consumers
 Decomposers
 Soil (This is included to show where decomposers return nutrients to for recycling back
into the ecosystem).
 Arrows – Arrows ALWAYS show how ENERGY flows (so they should begin with the
source of the energy and end at the organism gaining the energy.)
Practice with a small one: In a meadow, rabbits and snails eat grasses to survive.
Sometimes a fox catches the rabbit for a tasty meal. Birds also search for their food in the
meadow and sometimes capture snails. Draw a food web indicating the relationships described.
Make sure you include all the necessary information for a food web.
SUN
Decomposers
Fox
Birds
Rabbits
snails
Grasses
Nutrient rich Soil
One more practice with the information presented differently: Draw a food web
indicating these relationships. Include everything that is necessary!
Organism
Organism’s food
Arctic Wolf
Seals
Krill
Diatoms
Polar Bear
Seals, Arctic Cod
Seal
Arctic Cod, Krill
Artic Wolf
Polar Bear
SUN
Seals
Decomposers
Arctic Cod
Krill
Diatoms
Soil
3
Hoo Eats Who?
Purpose: To construct a food web using the relationships and pictures given.
Materials: Copy of animal figures sheet, tape or glue, scissors, colored pencils, large sheet
of paper (could use the back of scratch paper)
1.
2.
3.
4.
5.
6.
Method:
Turn a large sheet of paper the long way. Draw grass, seeds, flowers and plants along the
bottom.
Cut out the animal figures. Affix the owl to the top of your food web.
Arrange the other animals on the page with space left to draw arrows in between. Make sure that
your herbivores (primary consumers) are pasted nearest the plants, seeds and flowers. Then,
place the secondary consumers in the next “row” and so on until you reach the top of your food
chain … your owl.
Draw arrows from each animal to the animal that eats it. Make sure that your arrows are
indicating the direction of energy flow.
Also, make sure you draw in some decomposers and indicate that the decomposer will eventually
decompose all organisms in order to start the process all over again.
You must also include the sun as the provider of all energy. Make sure there are arrows from the
sun to the appropriate trophic level.
Data: (Use this to figure out Hoo eats Who)
Animal:
Owl
Field mouse
Vole
Bird
Shrew
Mole
Lizard
Grasshopper
Beetle
Moth
Decomposers
Food Source:
Field mouse, vole, bird, shrew, mole, lizard, grasshopper, beetle, moth
Grass, seeds, grasshopper, beetle, moth
Plant roots, grass, seeds, grasshopper, beetle, moth
Seeds, grasshopper, beetle, moth
Grasshopper, beetle, moth
Grasshopper, beetle, moth
Flowers, seeds, grasshopper, beetle, moth
Leaves, grass, seeds
Leaves, flowers, seeds
Flowers
Eventually – all energy goes here
Conclusion: Add your name to your food web!
1. Draw a food chain from your food web. Label the parts of the food chain.
Sun 
Grass 
Grasshopper  shrew  owl  decomposers
soil
2. Convert your food chain into an energy pyramid. Label energy transfer, loss and relative
biomass.
SUN
Decomposers
0.1%
90%
Owl (1)
1%
90%
Shrew (10)
Grasshopper(100)
100%
10%
90%
Grass (1000)
4
Biological Magnification:
Biological Magnification = build up of toxins within feeding relationships. The
further to the top of the food chain an organism is, the larger the quantity of
toxins is built up within their tissues.
Draw a diagram to help you remember/understand biological magnification:
Deadly Links:
Students will model grasshoppers, shrews and hawks to describe how food flows
through the ecosystem.
Conclusion Questions:
1. How does this activity relate to how energy flows through an ecosystem?
As the toxins move up in the food chain, the amount of toxins continues to increase
because the smaller organisms need to eat more of the plants to survive. The secondary
consumer then needs to eat multiple primary consumers to get the energy it needs,
therefore, building on the amount of toxins within its body. This is similar to the amount
of energy needed (number or organisms) for the secondary consumer to survive. It is in
reverse order though.
2. Explain two possible consequences of pesticides entering the food chain.
1 – kills other non-harmful organisms within the ecosystem
2 – contaminates our food and causes human illness due to its consumption
3. An ecologist studied the presence of a toxic chemical in a lake. She found the water had
one molecule of the chemical for every billion molecules of water. This is called part per
billion (1 ppb). The algae growing in that lake had one part per million (1 ppm) of the toxic
chemical. Small animals, called zooplankton had 10 ppm. Small fish had 100 ppm. Large
5
fish had 1000 ppm. How do you explain this increase in this toxic chemical to 1000 ppm
for the large fish?
The larger fish needs to consume multiple organisms, all of which ate the multiple smaller
organisms, who consumed plants that took in the toxins. Therefore, these toxins continue
to increase until it reaches the top of the food chain.
Also, what is the name of this process?
Biological magnification/Biological accumulation
4. The ecologist (from the previous question) found that this chemical in the lake was a
pesticide that had been sprayed on cropland 100 miles away from the lake. How did so
much of it get into the lake?
Rain that falls in this area removes the pesticides off the plants and it runs off to local
waterways. Ultimately, leading to the lake.
Trophic Level = a layer in the feeding relationship of an ecosystem, one link in the food
chain/web
All producers are in the same trophic level, all primary consumers are in the same trophic level,
and so on.
Biomass = total amount of organic material present in a trophic level.
(The more material = the more energy.)
Another way to look at trophic levels …
Ecological (or Energy) Pyramids:
A diagram that shows the relative amounts of energy/biomass in the different trophic levels. The
lowest trophic levels are at the bottom of the pyramid.
Biomass
0.1
%
__ MAN
MAN
10%
100 %
of the
sun’s energy
1%
Energy
Lost
during
90%
conversion
to heat,
waste….
90%
FOX
10%
10%
RABBIT
10
%
GRASS
90%
6
__ FOXES
___ RABBITS
______
Bunches of
GRASS
Energy Pipeline
Total Growth Chart
Round 1 Round 2 Round 1
Tally
Tally
Class total
Round 2
Class total
Autotroph
Herbivore
Carnivore
Decomposer
Analysis:
1. What are some of the ways energy is used at each trophic level?
2. Where did the plants acquire their energy? Why were there no limits on the amount
of “calories’ given to them?
3. How are plants limited in the real world? (Give at least three things that limit plant
growth.)
4. What would happen to the amount of energy needed for the entire system if the
carnivore had been allowed to “grow” to full size?
5. Why are food chains typically less than 4 trophic levels in length?
6. Why are there more plants on earth than carnivores?
7. Could a lower trophic level pass all its calories directly to a higher level?

What would be the consequences for the organisms involved?

How might this impact human food supplies as our world population (of
humans) keeps growing?
7
Practicing Drawing Ecological Pyramids:
Step 1: Draw a food web showing these relationships. Include all necessary parts:
Organism:
Hawk
Squirrel
Rabbit
Snake
Toad
Fox
Food sources:
Organism:
Rabbit, Squirrel, Mice, Cardinal
Nuts
Grass
Mice, Cardinal, Toad, Insects
Insects
Rabbit, Squirrel, Mice, Cardinal
SUN
Decomposers
Fox
Rabbit
Hawk
Squirrel
Mice
Snake
Cardinal
Toad
Insects
Grasses
Nuts
Soil
Step 2: Draw a single food chain from the web. Label the parts.
Sun  Grass
Producer
 Rabbit
Primary consumer
 Fox
Secondary consumer
 Decomposers
Soil
Step 3: Draw an ecological/energy pyramid showing the food chain. Label energy transfer,
energy loss and relative biomass.
SUN
Biomass
10 Fox
90%
Fox(10)
1%
100 Rabbit
1000 Gass
90%
Rabbit (100)
10%
100%
Grass(1000)
8
Carrying Capacity = The maximum population a community can tolerate for extended
periods of time. Usually determined by abiotic factors …
Abiotic Factors = non-living characteristics of the environment.
For example:
- Sunlight
- Moisture
- Space
- Pollution
- Landscape/Terrain
Limiting Factors = Anything that keeps a population from over-growing the resources
available.
Ecological Relationships:
Biodiversity: the number of species in an ecosystem
Territory = space claimed by an individual
organism
Ecological Equilibrium = state of “balance” in an
ecosystem
Niche = Role of organism in the ecosystem (job) http://www.fieldstonealliance.org/client/client_images/cartoon-find_niche.jpg
•


Niche Diversity = Number of niches in an ecosystem; often determined by
abiotic factors
A niche is the sum of all activities and relationships a species has while obtaining and using
resources needed to survive and reproduce.
Only 1 species can occupy a whole niche in an ecosystem at a time.
Types of Ecological Relationships:
Competition = When species or individuals “fight” for the same resources.
The “fight” may be ___indirect____ … the individuals may ___never_____ directly
contact each other.
9
Two species with similar needs for the same limited resources cannot coexist.
Keystone Species = a species that causes a large increase in diversity of its habitat.
Losing a keystone species usually ___disrupts_______ many ecological relationships.
Herbivory = A primary consumer feeds on a producer.
Predation = A consumer feeds on another consumer.
Symbiosis = a long-term relationship where two species live closely together and at least one
benefits directly from the relationship.
Types of Symbiosis:
Mutualism =
• Both organisms benefit
from the relationship.
• Win-Win situation!
Commensalism =
• One organism benefits,
the other one is
unaffected.
• Win-Neutral
relationship
10
Parasitism =
• One organism benefits,
the other one is
harmed!
• Win-Lose relationship
• Parasites rarely kill
their hosts…it would
require them to get
another one!
Career Critters
http://www.signs-up.com/prod_images/Critter_xing_thumb_640.jpg

Define the following terms:
Ecosystem— variety of organisms that live together within a given area

Erosion— removal of top soil by water or wind

Insecticide— a chemical applied to crops to kill insects

Manager— someone who supervises over others on a project or in a job

Niche— role an organism plays within an ecosystem
Procedure:
1. Each group will receive a copy of the Ecosystem map, a set of ecosystem cards, a set of critter
cards and a set of critter tokens.
 Using the ecosystem cards, locate each of the ecosystems on the map.

Where does the stream begin and end on the map? Trace its course.

Where is the golf course in relationship to the stream?

Where are the parking lots in relationship to the stream?

Where is the park in relationship to the other areas of town? Who do you think visits
the park?

Where is the prairie ecosystem in relationship to houses?

What areas or neighborhoods on the map are similar to where we live?
2. Hand out the critter cards to members in your group as if you were playing a card game.
When you receive the set of critter cards, read the back of the cards silently to yourself and
observe the illustrations on the cards. Keep the cards you were given.
11
3. Arrange the Critter tokens neatly around the edge of the map in any order. Your group
should have at least three of each different critter token.
4. Shuffle and stack the 12 ecosystem cards face down beside the map. One student draws a
card and reads it aloud to the group. Each student examines his/her own critter cards to
determine if those animals or plants could help solve the ecosystem problem described. If so,
the student explains how to the group. If the group agrees, a critter token of that plant for
animal is placed on the ecosystem map. Remember more than one plant or animal may be
used to solve the problems. There may be unused critter tokens at the end of the activity.
Continue drawing ecosystem cards until all are used.
5. When all the Ecosystem Cards have been drawn and all the ecosystem problems have been
solved, compare your results with the group next to you.
6. In your group, discuss and answer the following questions:
 Could any of these solutions backfire? In other words, could the plants or animals
used to help solve certain problems end up being a problem themselves?
Yes! Answers will vary

Are there other wild plants or animals (not used in this activity) that could have been
used to help solve the ecosystem problems?
Yes! Answers will vary

The gambusia fish is not native to many states. Is it okay to introduce non-native
(invasive) species to help with an ecosystem problem? What are the benefits? What are
the risks?
State your opinion. Yes or no. Then back it up. Benefits – kills mosquito larvae. Risks –
outcompete native fish.

How could the location of the 12 ecosystems on the map be redesigned to reduce some
of the environmental problems?
Answers will vary

Are there ways that animals, plants, and humans could work together to solve
environmental problems?
Yes – balance. Answers may vary
 In what ways is this activity realistic? Unrealistic?
The management of ecosystems is realistic. Humans are
actively trying to manage multiple ecosystems whether it’s a
farmer or the DNR.
http://www.thomasoandrews.com/album/drive/critter2.jpg
The unrealistic portion is the lack of optional resources. In this activity we used
organisms to manage the ecosystem. In society, they use multiple methods, for example,
hunting, pesticides, crop rotations, etc.
12
TCET Notes for (date): __________________________________
T
Title
 Read the title.
 Predict what article will be about.
Credibility
C
E
 Who wrote the article and what are
their credentials?—how long writing,
awards won, etc. You will have to
research this!
 Underline credible sources within
article itself
 Who published the article?
 When was the article published?
Essential Knowledge
 In one sentence, summarize the single
MOST important idea in this article.
1.
___________________________________________________________________
Textual Evidence
T
 Find three different lines from the
article that support and/or develop
what you decided was the author’s
purpose for writing the article
 You will turn in both the article and
this sheet on Friday.
2.
_____________________________________________________________________
3.
13
Ecological Succession:
Studying how ecological communities respond to change …
Ecological communities = the plants and animals found in an area.
Succession =
• Sequence of communities a region goes through over time.
• Change can occur for many reasons: new resources, disturbances, and biotic
changes.
Change can occur for many reasons: new resources, disturbances, and biotic changes.
Climax Community =
• A diverse, stable community.
Usually, the ______final_____ community in succession.
Primary Succession =
A sequence of communities forming in an originally lifeless habitat (no soil).
 Very ____slow______ process due to lack of ___soil__________.

Pioneer Species = the first species to inhabit an otherwise lifeless area
For example: lichen
o Lichen is fungi and algae living together in a mutually beneficial (symbiotic)
relationship:
o Algae = makes its own food and provides food for the fungi
o Fungi = breaks down organic material and makes soil

Disturbances that can lead to primary succession:
o Volcanic eruption
o Glaciers
o Rock Slides (maybe—depends if it’s just rock or rock and soil)
Secondary Succession =
A sequence of communities forming in an area with soil.
• Usually when a region has been cleared by a disturbance that does not destroy the soil.
 Pioneer species in secondary succession are generally species that grow ____quickly___
and disperse many ____seeds______ to colonize the area in a short time span.
 Usually when a region has been cleared by a disturbance that does not destroy the soil.
 Disturbances that can lead to secondary succession:
o
o
o
o
o
o
Flood
Fire
Hurricanes
Tornadoes
Human activity
Rock Slides
14
Pond Succession
Succession is a term used to describe the ever-changing environment and the gradual process by
which one habitat is replaced by another. Many habitats that appear to be stable are changing
before us – perhaps at a slow rate in human eyes, but evolving rather quickly according to
Earth’s clock.
For example, a shallow pond may be transformed into a marshy, then forested area in only a
thousand years or so. Wind-blown or water-borne spores of algae are the first inhabitants. Eggs
of flying insects are deposited. Small fish and amphibians arrive through the inlet. Surrounding
sediments begin to fill the pond, some borne on wash-out from rainfall, some entering through
the pond’s inlet. Marshy plants growing along the shoreline spread inward as sediments fill the
pond. Land plants also spread inward and replace the marsh plants as the ground is consolidated.
As more plants and animals enter the system, more opportunities for habitat become available to
others. Changes from ponds to forest are only one example of succession.
Directions and Questions:
1. What does a pond look like? What characteristics are included?
It has lots of plants growing within and around it. Frogs, ducks, insects, etc are also going to be
found around the pond.
2. Fold a blank piece of paper into thirds.
3. Draw a pond from a side view. Label as TODAY.
4. What kind of plants and animals might live in the water, near the shoreline and in the
surrounding area? Add some of those to your TODAY picture.
Marshy plants like cattails and lilly pads along with tall grasses growing around the pond. A
willow tree or a pine tree may be growing nearby. Turtles, frogs and snakes may be living
within the area. Lots of insects, dragon flies, etc which bring the birds. Raccoons may pop in
every now and then, fish are within the pond, leeches and other aquatic organisms as well.
5. Label the second section of your paper as 500 Years in the Future.
6. What changes in the environment have taken place?
Pond has decreased in its depth, losing some of its aquatic and plant life. Marshy plants start to
fill in the landscape where water has been lost due to sedimentation. Less animals like frogs and
turtles are within the area, they have moved on.
7. How will the pond look now?
Less like a pond, more like a wetland.
8. What lives and grows in the water now that it is much shallower and smaller? What lives
and grows around the shoreline now that it is marshier? What lives and grows in the
surrounding area?
Birds live in the area, insects, bats, etc. You will continue to have tall grasses, maybe some
buckthorn, trees are beginning to get taller now, creating more shade for shade grown plants.
9. Draw a picture of the pond area in 500 years.
10. Label the third section of your paper as 800 Years in the Future.
11. By this time, the pond is almost totally filled with sediment, leaving only a small marshy
area with perhaps a stream running through. What changes have taken place? Consider
what is living and growing in the environment.
15
The aquatic organisms have moved on or passed away due to lack of water (like fish). Instead of
cattails, you have tufts of grasses, it is not as easy to walk through with all of the vegetation
growing within the area. Some deer may come in to get some water and other larger organisms.
Less wading birds, instead you will have smaller insect eating birds. Insects will remain but
instead of dragon flies, you have smaller insects.
12. Draw a picture of the pond area in 800 years.
13. What effects does the pond succession have on the surrounding area?
The ecosystem completely changes allowing other organisms to thrive instead of organisms that
live within a pond. Now it is a forested wetland area that house a new variety of species.
16
Forest Time-Lapse Activity:
(Activity from: Project WILD Curriculum and Activity Guide, Council for Environmental Education)
Background: Ecological succession refers to the sequence of organisms that sequentially occupy an
area over a period of time. Such changes can be observed over time in a plowed field or an area burned
by a forest fire. Succession also refers to the process of change by which these communities replace each
other and to how the environment becomes altered over time.
Succession occurs in every type of environment, although the details vary depending on the type of
ecosystem. Succession can be categorized by three forces that may drive the change: (1) physical
changes produced by resident organisms, such as shading by trees, (2) geological processes, such as
filling in of a lake with sediment, or (3) biogenic changes, such as the introduction of a predator or
consumer, invasive exotic plants or animals, or a disease.
Within any community of plants and animals, succession proceeds over time to result in a final stage
called a “climax community.” Even though the composition and structure of the climax community is
determined by the regional climate, the pattern of stages to get to the climax often is variable. Within any
region, there is a variety of physical environments. The extremes of the physical environment eventually
are modified by the combined activities of the organisms during the successional process. Also, many
factors can intervene to prevent an area from reaching its climax condition, such as fires, special soils,
introduction of exotic plants that out-compete the natives for sunlight and nutrients, and the activities of
grazing animals. Agriculture and forestry plantations also set back succession.
Introduction: An area of forest has been clean harvested and abandoned. A fire occurred on
the site after it was abandoned.
What happens to the site over time?
3 to 5 Years Later:
The first plants to invade prefer bright sunlight. The fire released many of the nutrients in stumps and
branches left behind during the cutting of the area. Grasses – such as broom straw, golden rod, and other
herbaceous plants – have taken over the area. The area is also green with sprouts from tree stumps that
were not killed by the fire. Woody shrubs – such as blackberry, wild grape, sumac, and viburnums – are
beginning to grow. Here and there, a young coniferous tree – such as red cedar or field pine – is
beginning to reach above the grasses.
15 to 25 Years Later:
The overall vegetation is dense as the plant community converts from shrubby field to forest. Maples,
birches, oaks and other hardwoods join pines and cedars. Few acorns and other nuts are being produced.
Vertical layers are becoming distinct. At 25 years, the young hardwoods are approximately 40 feet tall
and starting to shade out “sun-loving” shrubs such as blackberries and brambles. Other shrubs more
tolerant of shade – such as blueberry, serviceberry, and spice brush – may continue to grow, although the
blueberry will not produce as many berries. Hemlock and white pine, which thrive in under-story shade,
may begin to grow.
More than 100 Years Later:
As taller plants occupy the site, less light is available on the surface of the forest. Plants tolerant of
shading will out-compete plants that are intolerant of shading, and gradually the composition of the forest
will change to favor shade-tolerant species. Distinct layers can be identified in mature forests. The
canopy layer consists of trees 60 to 100 feet high, including mixed oaks, hickories, sugar maple, beech,
birch, or other hardwoods, or hemlock and white pine. And understory layer 30 to 40 feet high has trees
such as dogwood, hornbeam, and saplings. Below this understory, a shrub layer about 3 to 4 feet high,
might include blackberry, arrowwood, spicebrush, blueberry, or huckleberry. Poison ivy, Virginia
creeper, and Japanese honeysuckle are vines that span all layers. An herbaceous (nonwoody) layer of
perennial, annual and biennial plants is found at the forest floor.
Your assigned timeframe = __________________________________
17
Descriptions of Plants and Animals:
You will need to review these plants and animals to determine the types of species (plant and
animal community) found during your timeframe in your forest.
Grass/Herb: Grasses and herbs cannot
tolerate excessive shade. They grow quickly,
but have nonwoody stems and do not reach a
great height.
Deer: Deer eat grasses, shrubs, and crops.
They prefer an edge community where they
can hide but also venture periodically into open
areas to browse.
Shrub: Shrubs have woody stems and are
usually intermediate in height between grasses
and trees. They can tolerate some shade.
Grasshopper: Grasshoppers live in grassy
areas and eat grass, clover and other herbs.
Sapling: Saplings are trees that have not
reached full height. They may be the size of
large shrubs.
Mature tree: These trees have reached their
full height and form the canopy layers.
Songbird: Songbirds in this area live in
mature trees.
Rabbit: Rabbits live in edge communities
where there is plenty of shrub cover to hide,
plus grasses and other herbs to eat.
Quail: Quail nest in shrub areas where they
have cover, but they may feed in more open,
grassy spaces that supply many insects.
Sparrow: Sparrows nest in shrub and tree
areas where they have cover but may feed in
more open spaces that supply many insects.
Squirrel: Squirrels build their nests in trees
but are seen on the ground and moving through
tree branches. They eat fruit, berries, and nuts.
Cardinal: Cardinals are red to brownish-red
birds that nest in the high branches of shrubs or
low branches of trees. They feed on berries,
Garter snake: This snake lives in grassy areas seeds, and insects gathered from plants or from
and shrubs. It eats toads, earthworms, small
the ground.
birds, and mammals.
Robin: Robins live in edge communities
Toad: Toads live in meadows and shrub lands. where there are open grassy spaces, shrubs,
They eat insects and other invertebrates.
and small trees. They build their nests in the
branches of younger trees and eat berries,
Wild turkey: Turkeys roost in trees and need worms and insects.
clearings and brushy fields for nesting.
Fox: Foxes live in burrows called dens. They
Mouse: Mice live in burrows and eat berries,
prefer some ground cover for hunting, and they
grains and insects.
feed on birds, mice, rabbits, insects, and
berries.
Owl: Owls in this area nest in trees but hunt
the ground for mice and shrews.
Black bear: Bears live in the thick forest
where they have plenty of cover. They eat a
variety of plant and animal matter.
18
Geochemical Cycles
Carbon Cycle:

Carbon is primarily found in the atmosphere as CO2.

The Earth’s early atmosphere was ____95%___ CO2. Mainly due to the introduction of
photosynthetic plants, the atmosphere is now ____0.04%___ CO2.

_____Photosynthesis_________ and ____Cellular Respiration_______ form a
continuous cycle of carbon movement.

Sources of carbon include: Fossil Fuels, Coal, oil, proteins in plants and animals,
decomposed material
Carbon Cycle Diagram
http://blogs.wvgazette.com/coaltattoo/files/2009/04/carbon-cycle.gif
Human Effects on the
Carbon Cycle
Burning of fossil fuels
increases the amount of
carbon in the
atmosphere.
This material was
“fixed” underground but
as humans we use it to
heat our homes, for
transportations, etc.
Therefore, adding it
back into the
atmosphere.
http://blog.wired.com/wiredscience/
19
Nitrogen Cycle:

Living organisms require nitrogen in order to form amino acids which are used in the
building of proteins.

78% of our atmosphere is nitrogen, BUT most organisms

_____Nitrogen Fixing Bacteria_ CAN use N2 from the atmosphere.
o They convert atmospheric N2 into ___Ammonia_________ (NH4) which is a form
of nitrogen that ___Plants______ CAN use.
o They live in the soil
o They also convert N2 into ____Nitrites_______ and ____Nitrates____.



Animals get their nitrogen from the plants they eat or animals they eat that eat the plants
Decomposers return nitrogen to the soil in the form of __________ and the cycle repeats.
So, oftentimes, the nitrogen cycle does not even require the nitrogen to be returned to
atmospheric form.
Humans affect the
Nitrogen Cycle
Nitrogen Cycle Diagram
http://www.uwsp.edu/geO/faculty/ritter/geog101/textbook/earth_system/nitrogen_cycle_EPA.jpg
Humans increase
amount of nitrogen
within cycle by burning
of fossil fuels, adding
fertilizers, driving,
smog, increase
greenhouse gases,
runoff into waterways
is a pollutant,
20
Traveling Nitrogen Passport
Incredible Journey
Great News: In this game, you are a nitrogen atom! You are going to travel the nitrogen cycle
and, along the way, you will be stopping in many exciting locations – some of which you
probably have never been to before.
Directions:
1. Record your starting position.
2. Roll the die to find out where to go next.
3. Record where you went and how you traveled.
4. Go to that location in the room and roll again.
Starting Position =
Record of Travels:
Trip #1: How I traveled:
Where I went:
Trip #7: How I traveled:
Where I went:
Trip #2: How I traveled:
Where I went:
Trip #8: How I traveled:
Where I went:
Trip #3: How I traveled:
Where I went:
Trip #9: How I traveled:
Where I went:
Trip #4: How I traveled:
Where I went:
Trip #10: How I traveled:
Where I went:
Trip #5: How I traveled:
Where I went:
Trip #11: How I traveled:
Where I went:
Trip #6: How I traveled:
Where I went:
Trip #12: How I traveled:
Where I went:
21
Assignment:
You must creatively describe your journey as a nitrogen atom. This can be done by writing a
children’s story, a poem, or a comic strip. Your story must provide a basic understanding of the
nitrogen cycle and the way that nitrogen moves. Use your imagination for how you can express
the necessary aspects in an interesting and creative manner. Extra credit on the assignment can
be earned for interesting/creative work. Extra credit on the outcome exam can be earned for
exceptional work (both creative and informative).
You will be graded on: format of the story/poem/comic, spelling and grammar, creativity and
proper description of the concept of the nitrogen cycle.
Outline or Brainstorm of Story:
Use the space below to brainstorm you
22