Biology 1
Ecology
FullName:____________________________Period:________
MatterandEnergyFlowthroughthebiosphereandthroughecosystemsvia
bioticandabioticprocesses.Organismsbothcooperateandcompetein
ecosystems,andtheseinterrelationshipsandinterdependenciesleadto
ecosystemstability.
TheGuidingQuestions
1. Howdoesmatterandenergyflowthroughanecosystem?
2. Whataresomecommonrelationshipsbetweenorganismsinanecosystem?
3. Howdohumansmodifyecosystems?
4. Howcanpeoplethoughtfullymanageecosystemresourcessotheyare
sustainable?
LearningOutcomes
Bytheendofthistopic,youshouldbeableto:
!explainthetermspopulation,community,habitat,ecosystem,biome,biosphereandgiverelevant
examples
!describeexamplesofvariationamongspeciesandwithinspecies
!identifyexamplesofnichesanddescribetheroleofvariationinhelpingcloselyrelatedliving
thingstosurviveandinthesameecosystem
!describebioticandabioticfactorsinanecosystemandexplaintheiraffectsononeanother
!Identifyandgiveexamplesofrelationshipsinecosystems:predation,herbivory,symbiosis,
mutualism,commensalism,parasitism
!Usequadratstomeasurebioticfactorsinahabitat,andanalyzedatausingt-tests
!Explainandconstructfoodchains,foodwebs,andtrophicleveldiagrams
!Describethetransferofmatterandenergyalongafoodchain,includingthe10%rule
!Describetheglobaleffectsoftropicalrainforestdeforestation,includingleaching,soilerosion,
disturbanceofthewatercycleandbalanceofatmosphericoxygenandcarbondioxide,lossofhabitat
andlossofbiodiversity
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Biology 1
Ecology
VocabularyPages
Bytheendofthistopic,youshouldbeabletodefineandcorrectlyusethefollowingterms:
Biotic
Abiotic
Population
Community
Habitat
ecosystem
Biome
Biosphere
Niche
Species
Predation
Herbivory
Mutualism
Commensalism
Parasitism
Symbiosis
t-test
Foodchain
FoodWeb
TrophicLevel
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Biology 1
Ecology
Producer
Consumer
Primaryconsumer
Secondaryconsumer
Tertiaryconsumer
Decomposer
Saprotrophs
Detritivores
CarbonCycle
Combustion
Decomposition
FossilFuels
Biodiversity
Sustainability
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Biology 1
Ecology
Definethefollowing:
Ecology:
Biotic Factors:
Abiotic Factors:
Label some of the biotic and abiotic factors of this grassland ecosystem:
DefinitionofSPECIES:
Distinguish between habitat and niche. Give an example for a particular organism.
How is an animal’s niche related to variation and adaptation?
LevelsofLife
Organism(anysinglelivingthing)
à__________________(membersofsamespecieslivinginoneplace)
à__________________(differentpopulationslivinginanarea)
à_________________(communitylivinginasimilarhabitat) à_____________(ecosystemscoveringwideareasaroundtheEarth)
à_______________(allthelivingandnon-livingthingsonEarth)
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Biology 1
Ecology
PopulationEcology
Whatarethetwopartsofthedefinitionof“population”andgiveanexample.
Factorsthatincreasepopulationsize: Factorsthatdecreasepopulationsize:
Resources=
EnvironmentalResistance(LimitingFactors)=
CarryingCapacity=
PopulationGraphs:Forthegraphtotheleft,discusswhatishappeninginterms
ofresourcesandpopulationsize.
1.)Growth(Exponential)Phase-
2.)Transitional(Log)Phase-
3.)Stationary(Plateau)Phase-
Populationdensity=
Density-dependentlimitingfactors=
Density-independentlimitingfactors=
5
www.explorelearning.com
User: Bio1student Password: student
Student Exploration: Rabbit Population by Season
Vocabulary: carrying capacity, density-dependent limiting factor, density-independent limiting
factor, limiting factor, population, population density.
Note: these key vocabulary terms are defined at the end of this activity (flip a few pages ahead)
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1. Suppose you had a pet rabbit. What would the rabbit need to stay alive and healthy?
_________________________________________________________________________
_________________________________________________________________________
2. A female rabbit can give birth to over 40 baby rabbits a year. Suppose all of her offspring
survived and reproduced, all of their offspring survived and reproduced, and so on. If that
happened, in only eight years the mass of rabbits would exceed the mass of Earth!
So, why aren’t we overrun with rabbits? What keeps the rabbit population in check?
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
Gizmo Warm-up
A population is a group of individuals of the same
species that live in the same area. The size of a
population is determined by many factors. In the Rabbit
Population by Season Gizmo™, you will see how
different factors influence how a rabbit population grows
and changes.
1. Select the BAR CHART tab. What is the size of the
initial rabbit population? ______________
2. Select the TABLE tab. Click Play (
), and allow the simulation to run for one year.
A. In which season did the rabbit population increase the most? __________________
B. In which season did the rabbit population increase the least? __________________
Activity A:
Carrying capacity
Get the Gizmo ready:
 Click Reset (
).
Question: What determines how large a population can grow?
1. Think about it: A limiting factor is any factor that controls the growth of a population. What
do you think are some of the limiting factors for the rabbit population? _________________
_________________________________________________________________________
_________________________________________________________________________
2. Run Gizmo: Select the DESCRIPTION tab. Set the Simulation speed to Fast. Select the
GRAPH tab. Click Play, and allow the simulation to run for at least 10 years. (Note: You can
use the zoom controls on the right to see the whole graph.)
A. Describe how the rabbit population changed over the course of 10 years.
___________________________________________________________________
___________________________________________________________________
B. What pattern did you see repeated every year? _____________________________
___________________________________________________________________
___________________________________________________________________
C. How could you explain this pattern? ______________________________________
___________________________________________________________________
___________________________________________________________________
3. Analyze: The carrying capacity is the maximum number of individuals of a particular
species that an environment can support. All environments have carrying capacities.
A. What is this environment’s approximate carrying capacity for rabbits? (Note: Average
the summer and winter carrying capacities.) ________________________________
B. When did the rabbit population reach carrying capacity? Explain how you know.
___________________________________________________________________
___________________________________________________________________
Activity B:
Density-dependent
limiting factors
Get the Gizmo ready:
 Click Reset.
 On the SIMULATION pane, make sure Ample is
selected for the amount of LAND available.
Introduction: Population density is the number of individuals in a population per unit of area.
Some limiting factors only affect a population when its density reaches a certain level. These
limiting factors are known as density-dependent limiting factors.
Question: How does a density-dependent limiting factor affect carrying capacity?
1. Think about it: What do you think some density-dependent limiting factors might be?
_________________________________________________________________________
_________________________________________________________________________
2. Predict: Suppose a shopping mall is built near a rabbit warren, leaving less land available for
rabbits. How will this affect the environment’s carrying capacity?
_________________________________________________________________________
3. Experiment: Use the Gizmo to find the carrying capacity with Ample, Moderate, and Little
land. List the carrying capacities below.
Ample: _________________ Moderate: _________________ Little: _________________
4. Analyze: How did the amount of space available to the rabbits affect how many individuals
the environment could support? _______________________________________________
_________________________________________________________________________
5. Infer: Why do you think limiting a population’s space decreases the carrying capacity?
_________________________________________________________________________
_________________________________________________________________________
6. Challenge yourself: Other than space, what might be another density-dependent limiting
factor? Explain. ____________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
Activity C:
Density-independent
limiting factors
Get the Gizmo ready:
 Click Reset.
 On the SIMULATION pane, select Ample for the
amount of LAND available.
Introduction: Not all limiting factors are related to a population’s density. Density-independent
limiting factors affect a population regardless of its size and density.
Question: How do density-independent limiting factors affect how a population grows?
1. Think about it: What do you think some density-independent limiting factors might be?
_________________________________________________________________________
_________________________________________________________________________
2. Gather data: Click Play. Allow the population to reach carrying capacity. Click Pause ( ).
Select the GRAPH tab and click the camera ( ) to take a snapshot of the graph. Paste the
snapshot into a blank document. Label the graph “Normal Weather.”
3. Predict: How do you think a period of harsh winters will affect the rabbit population?
_________________________________________________________________________
_________________________________________________________________________
4. Investigate: Click Reset. Select Harsh winter from the CONDITIONS listed on the
SIMULATION pane. Click Play, and observe the how the population changes over five
years. Paste a snapshot of the graph in your document. Label the graph “Harsh Winter.”
A. How does the Harsh Winter graph differ from the Normal Weather graph? ________
___________________________________________________________________
B. What do you think most likely caused the differences seen in the two graphs?
___________________________________________________________________
___________________________________________________________________
5. Predict: Rabbits reproduce in the spring. How do you think a period of cold springs will affect
the rabbit population? _______________________________________________________
_________________________________________________________________________
(Activity C continued on next page)
Activity C (continued from previous page)
6. Investigate: Deselect Harsh winter. Select Cold spring. Click Play, and observe the how
the population changes over a period of five years. Paste a snapshot of the graph in your
document and label the graph “Cold Spring.”
A. How does the Cold Spring graph differ from the Normal Weather graph? _________
___________________________________________________________________
B. What do you think most likely caused the differences seen in the two graphs?
___________________________________________________________________
___________________________________________________________________
7. Predict: How do you think a period of hot summers will affect the rabbit population?
_________________________________________________________________________
_________________________________________________________________________
8. Investigate: Deselect Cold spring. Select Hot summer. Click Play, and observe the how
the population changes over a period of five years. Paste a snapshot of the graph in your
document. Label the graph “Hot Summer.”
A. How does the Hot Summer graph differ from the Normal Weather graph? ________
___________________________________________________________________
B. What do you think most likely caused the differences seen in the two graphs?
___________________________________________________________________
___________________________________________________________________
9. Think and discuss: Other than unusual weather, what might be another density-independent
limiting factor that could affect the rabbit population? If possible, discuss your answer with
your classmates and teacher.
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
Vocabulary: Rabbit Population by Season
Vocabulary

Carrying capacity – the maximum number of
individuals of a particular species that an
environment can support.
o

Density-dependent limiting factor – a limiting factor that only affects a population when
its density reaches a certain level.
o

Examples of limiting factors include competition, disease, living space, natural
disasters, predation, and unusual weather.
Population – a group of individuals of the same species that live in the same area.
o

Unusual weather is one example of a density-independent limiting factor.
Limiting factor – any factor that prevents a population from growing larger.
o

The amount of available living space is one example of a density-dependent
limiting factor.
Density-independent limiting factor – a limiting factor that affects a population regardless
of its size and density.
o

Before a population reaches its carrying
capacity, it grows rapidly. As the population
nears its carrying capacity, growth slows.
Once the population is at carrying capacity,
overall growth stops as the population
stabilizes. The population will remain at the
carrying capacity until a limiting factor in the
environment changes.
A population is one of the levels of organization of the biosphere, the parts of
Earth where organisms live. The levels of biosphere organization from smallest
to largest are:

Individual organism

Population

Community (all of the populations living in the same area)

Ecosystem (a community and its non-living environment)

Biome (a group of similar ecosystems)

Biosphere
Population density – the number of individuals in a population per unit of area.
o
If 50 rabbits are living on a square kilometer of land, the population density would
be expressed as 50 rabbits/km2.
Biology 1
Ecology
CommunityInteractions:
NameofInteraction
TypeofInteraction
Key:
+=helped;-=harmed;
0=neitherhelpednorharmed
Mutualism
Commensalism
Parasitism
Predation
Competition
Examples
Don’tjustlisttwoorganisms.
(Addhoweachiseitherhelped,harmed,or
unaffectedbeinginthatrelationship)
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Biology 1
Ecology
EnergyFlowinEcosystems
TrophicLevels:Thelevelatwhichanorganismobtainsenergy(itsfood).
Producers:Definetheprefixandbasewordoftheterm“autotroph”anddiscusstheirroleinnature.
Consumers:Definetheprefixandbasewordoftheterm“heterotroph”anddiscusstheirroleinnature.
Definetheseexamplesofconsumersintermsofhowtheyobtaintheirfood:
Herbivore-
Carnivore-
Decomposer-
Totheleft,define(intermsofhowtheyobtaintheirenergy);Totheright,listthetrophiclevel
Special Heterotrophs: The Decomposers (nutrient recyclers!)
Detritivores
Saprotrophs
Howtheygettheirenergy
Examples
7
Biology 1
Ecology
Fill in the circles on the diagram below
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Biology 1
Ecology
Food Chains vs Food Webs
What is the definition of a food chain? What does it show?
What do the arrows on the
diagram represent?
How does a food web differ from a food chain? What does it show that a chain doesn’t?
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Biology 1
Ecology
Energy Transfer in Ecosystems
On average, how much energy is
transferred on to the next
trophic level?
Notice what’s happening at the
first trophic level. What
percentage of light energy can
plants capture through
photosynthesis?
How much more food would the world have if we all ate one trophic level down’?
How is this an argument for becoming a vegetarian??
A law of physics says that energy cannot be created nor destroyed. So why doesn't all
the energy from one trophic level get transferred to the next trophic level? Where
does the ‘lost’ energy go?
1.
2.
3.
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Biology 1
Ecology
Biogeochemical Cycles
Define the word parts to make meaning of this concept:
bio –
geo –
chemical –
cycle Cycles in Nature:
ALL living things need both _______________ and _________________.
Matter and energy are transferred:
• between organisms
• and between ____________________________________________.
What is different between the transfer of ENERGY and the transfer of MATTER?
ENERGY:
MATTER:
Materials are constantly and naturally ________________ through an ecosystem.
The main components that are recycled are _________, __________ and __________.
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Biology 1
Ecology
TheCarbonCycle
Fillintheblanksinthediagram.
What are two primary ways that carbon can get into the atmosphere?
1. __________________________
2. __________________________
What is the primary way that carbon comes out of the atmosphere?
__________________________
What current percent of the atmosphere is carbon dioxide? ______
How does that compare the to CO2 levels from 30 years ago?
Cycles in nature are fragile. How has the human-induced combustion of fossil fuels
changed the balance of the Earth’s carbon cycle?
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Biology 1
Ecology
Biodiversity
Whatdoesbiodiversitymean?
Whatarethe3componentsofmeasuringbiodiversity?
1.
2.
3.
Theworldisfulloflife.Biodiversityisprettycool,butwhocares?
Shouldwebeconcernedaboutlosingbiodiversity?Whyorwhynot?
1.Well,argumentsforprotectingbiodiversityfallintotwocategories:
biodiversityhasintrinsicvalue: biodiversityhasutilitarianvalue:
2.Whyisbiodiversitysoimportant?Providespecificexamplesofhowwevaluebiodiversity.
3.Whatisthecurrentconcernaboutextinction?
4.Whataresomeofthemajorthreatstobiodiversity?
5.Whataresomeactionspeoplecantaketoprotectbiodiversity?
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Biology 1
Ecology
Reversing Tropical Deforestation: Agroforestry and
Community Forest Management in Thailand
The Story
The story of Khao Din village began in the 1950s, when poor farmers moved to a new area of forest land
recently opened for settlement. The soil of the newly cut forest was rich, and the crop harvests were bountiful.
There were edible plants growing wild near the houses; the fish in the streams were easy to catch; and animals
such as wild boars roamed nearby. With such abundance at hand and a cooperative spirit among the villagers,
life was good.
However, things started to change in the 1960s when the Thai government began encouraging farmers to grow
cash crops for export. It provided loans to farmers for hybrid seed, chemical fertilizers, pesticides, and farm
equipment to grow crops such as rice, maize, jute fiber, and cassava, each farmer specializing in a crop for sale
instead of growing a diversity of food crops for his family. The farmers cut more forest to expand their farmland
and sold the timber as a bonus. They never had so much money before and started purchasing electronic
appliances, motorcycles, and other modern merchandise.
But soon crop prices began to decline as many farmers grew the same products. Matters worsened when
droughts came and crops started to fail. As desperate farmers went deeper into debt, they were forced to cut even
more forest to expand their fields, until there were almost no trees left. Streams and wild animals disappeared,
and heavy rains washed away the unprotected topsoil. Soil fertility declined even further because the supply of
animal manure decreased when people got rid of draft animals such as water buffalo as they mechanized their
farming. Farmers applied larger quantities of costly fertilizer to their damaged soil, trying to increase their yields
as much as possible.
Eventually, their fertilizer, pesticide, and farm equipment costs were so high, and their crop harvests so low, that
they were not earning enough money to buy food for the family. Villagers started moving to cities in search of
work, and families were split up. The people were torn from their traditional social ways, and juvenile
delinquency appeared for the first time. Trust, cooperation and their sense of community began to fall apart.
Fortunately the story does not end there. In 1986, a team from the nonprofit organization Save the Children was
sent to Khao Din village by the Thai government. Instead of providing charity, Save the Children was
determined to help Khao Din find sustainable solutions. At first, the villagers were suspicious of these strangers,
but after many long discussions, the villagers realized that they themselves were the cause of their problems
because of the way they had been using their land. With this shared awareness came the will to plan actions that
would bring restoration. As Buddhists, they strongly believed in a harmonious relationship with nature, and they
knew that restoring that harmony was the key to their survival.
Save the Children helped the villagers to map out their own solutions to the crisis. The villagers decided that
instead of relying on a few cash crops grown in monocultures, with a single crop filling each field, they would
design diverse “agroforestry” systems with a variety of useful trees and crops mixed together on the same fields,
resembling in many ways the structure of a natural forest. Their abandoned traditional methods had incorporated
many of the same elements, and the older villagers remembered how it worked.
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Biology 1
Ecology
Reversing Tropical Deforestation (continued)
They started by trying it on just a few farms. Within one growing season those families were able to feed
themselves again, saving dramatically on food costs. The diversity of crops provided a balanced and nutritious
diet. Year-by-year, more villagers, convinced of the advantages, adopted similar approaches on their own farms.
The full benefits of agroforestry unfolded over the next five years as the trees matured. Agroforestry produced a
larger quantity of food because the diversity of trees and crops filled the farm space throughout the year. And the
agroforestry was organic, with no costly and environmentally destructive chemical fertilizers or pesticides. It
could function without chemicals because it copied the structure of a natural forest in a way that allowed nature
to do the work of restoring and maintaining soil fertility. The trees bore fruit for the kitchen table and for sale,
and their leaf fall supplied organic fertilizer to replenish the soil. The dense vegetation protected the soil from
erosion and provided natural pest control because each crop pest, specializing in a particular crop, had difficulty
finding its food in a field full of other plants. Ponds holding irrigation water produced fish for home and sale.
And with so many crops, if one crop failed, or had a poor price in the market, others would succeed. In addition,
villagers could now build thriving cottage industries that processed the goods of their land.
The villagers also decided to establish a community forest. To protect the forest, they agreed on rules for
harvesting its resources. Only Khao Din villagers were allowed. The restored forest provided fruits, nuts,
medicines, building materials – and firewood for cooking. Soil erosion was reversed, and the damaged watershed
repaired itself. Streams and wild animals reappeared.
Khao Din’s village leader formed an “Association of Agriculture, Environment, and Development” to unite and
organize the villagers and spread their success to forty villages in the surrounding area. Their pride and
achievement gained even more momentum when Thailand’s beloved king gave his moral support to their efforts.
Now thousands of families are pursuing a variety of locally designed forms of agroforestry and sustainable
agriculture on land covering thousands of acres. Natural forests, largely devastated by misuse, are regenerating
over an even larger area. With productive land for farming right at home, migration to the cities has slowed
down, so the villages once again have a balance of men and women of all ages to strengthen the community and
care for the young. These people are not earning as much money as they once dreamed, but they can once again
count on the land and each other for support and nurture.
As a bonus, Khao Din and its neighbors have helped to combat global warming. Tropical deforestation is
responsible for more carbon dioxide emissions than every car, truck, airplane, train, and ship on the planet
combined. The destruction of Khao Din’s forests put carbon dioxide into the atmosphere, but the return of trees
to their landscape removed carbon dioxide from the atmosphere and put that carbon back on the land. By
following Khao Din’s example, farmers throughout the tropics could help reduce greenhouse gases while
securing a better life for themselves. The way Khao Din arrived at that solution – by shared community
awareness and action – can serve as an example to us all, no matter where we live.
15
Biology 1
Ecology
Reversing Tropical Deforestation
Feedback Diagrams: Negative and Positive Tip
Instructions: Fill in the blanks in the boxes, writing “more” to indicate an increase during the story’s
period of decline, or “less” to indicate a decrease during that period. Draw arrows between boxes to
show which factors were affecting other factors strongly enough to cause their increase or decrease.
There should be at least one arrow pointing away from each box and at least one arrow pointing into
each box. Finally, trace circular patterns of the arrows that represent “vicious cycles” that were set in
motion by the negative tipping point and driving decline.
16
Biology 1
Ecology
Reversing Tropical Deforestation
Feedback Diagrams: Positive Tip
Instructions: Fill in the blanks in the boxes, writing “more” to indicate an increase
during the story’s period of restoration, or “less” to indicate a decrease during that
period. Draw arrows between boxes to show which factors were affecting other factors
strongly enough to cause their increase or decrease. There should be at least one
arrow pointing away from each box and at least one arrow pointing into each box.
Finally, trace circular patterns of the arrows that represent “cycles” that were set in
motion by the positive tipping point and driving restoration.
17
Biology 1
Ecology
Reversing Tropical Deforestation
Analysis:
What are the negative effects of tropical deforestation:
1.) to the ecosystem
2.) to the community
3.) to the world
References:
Prepared by Gerry Marten and Julie Marten (EcoTipping Points Project)
http://ecotippingpoints.org/education/how-success-works-thailand/index.html#n2
Video Presentation: http://www.youtube.com/watch?v=cbVDwM_xSjU
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