Download 10 kcal/m 2 /year

Name _________________________________________________________Date _________Period _______
All About Ecology
Honors Biology – refer to Chapter 41
Biology – refer to Chapter 34
1. What is Ecology?
2. What does the Biosphere contain? ________________________________________________________________
3. All living things depend on two main factors for their survival. Name, describe and give
examples of each.
A. ________________________________________________________________________________________________________
B. ________________________________________________________________________________________________________
4. Ecology is the study of organisms and their relationships with the biotic as well as the
abiotic factors: Define each of the following levels and give an example:
A. Organisms: _______________________________
B. Population _______________________________
C. Communities ___________________________
D. Ecosystems ______________________________
E. Biosphere ________________________________
Biology –Chapter 36
Hons – Chapter 41
Feeding relationships in the Ecosystem
All living things require energy to survive. Define and give examples of each of the following:
Producers or Autotrophs: ____________________________________________________________________________
Consumers or Heterotrophs: _________________________________________________________________________
Decomposers or Heterotrophs: ______________________________________________________________________
Herbivores: _____________________________________________________________________________________________
Omnivore: ______________________________________________________________________________________________
Producers get their energy from the _______________.
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Energy flows through the ecosystem in ONE DIRECTION. It flows from the sun or inorganic
compounds to the producers. The consumers then eat the producers. A food chain is a
sequence of who eats whom. It is a series of steps that show the transfer of energy from one
level (called trophic level) to the next. The arrows denote the direction of energy flow. For
example the energy flows from the algae to the mosquito larva as it eats the algae. Therefore
the arrow is directed from the algae to the mosquito larvae.
1. All food chains start with which type of living thing?
2. The first organism in each food chain must always be what type of organism?
3. Where do chemosynthetic bacteria get their energy?
4. Define herbivore? Herbivores are also called _______________
5. The animals that feed on the herbivores are also called? _____________________
6. Animals that are able to eat both producers and consumers are called? __________________
7. Secondary consumers are eaten by larger ______________________________
8. ___________________ consumers eat the secondary consumers.
9. Write a food chain consisting of one producer and 3 consumers. Write
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FOOD WEBS: Interconnected food chains.
1.
What is used to indicate the flow of energy in a food chain or food web? ________________
2.
What is a food web? ____________________________________________________________________________
3.
Write 2 different food chains from the diagram above.
Food Chain 1 __________________________________________________________________________________________
Food Chain 2 __________________________________________________________________________________________
4.
Were there any organism/s that was common to both of the food chains? Which ones?
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Trophic Levels:
The trophic level of an organism is the position it holds in a food chain.
1.
2.
3.
4.
5.
6.
Producers - First trophic level
Primary consumers are in the second trophic level
Secondary consumers eat primary consumers. They are in the third trophic level
Tertiary consumers are in the fourth trophic level.
Quaternary consumers are the fifth trophic level
Food chains "end" with top predators, animals that have little or no natural enemies.
When any organism dies, it is eventually eaten by detrivores (like vultures, worms
and crabs) and broken down by decomposers (mostly bacteria and fungi), and the exchange
of energy continues.
Some organisms' position in the food chain can vary as their diet differs. For
example, when a bear eats berries, the bear is functioning as a primary consumer. When a
bear eats a plant-eating rodent, the bear is functioning as a secondary consumer. When the
bear eats salmon, the bear is functioning as a tertiary consumer (this is because salmon is a
secondary consumer, since salmon eat herring that eat zooplankton that eat phytoplankton,
that make their own energy from sunlight). Think about how people's place in the food
chain varies - often within a single meal!
Use the Food web from page 3 to place each organism in the correct trophic level. Three of
the organisms have been done for you.
First trophic
level
Robin
Bug
Ladybug
Second
Trophic level
Third trophic
level
X
Fourth
Trophic level
X
Fifth trophic
level
X
X
X
1.
The 1st trophic level consists of _______________ consumers called _________________.
2.
Name the 2nd trophic level (both names). __________________________________________
3.
Secondary consumers may be _______________ eating meat or _______________ that eat both
plants and animals.
4.
What is the 3rd trophic level called? ____________________________
5.
What is the 4th trophic level called? _______________________________
6.
At the 5th trophic level would be _____________ consumers that eat _____________ consumers.
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Energy Flows through the Ecosystem:
Energy from the sun is used by autotrophs and converted to energy in the chemical bonds of
organic compounds Ex. Sugars. This allows the plant to grow (increase in mass) and
reproduce (increase in numbers). Heterotrophs then eat the autotrophs, use the energy in the
organic food in order to survive, grow and reproduce. However, when energy I changed from
one from to another, much of that energy is lost as heat and other forms than cannot be used
for useful work in the next level. Additionally some energy remains at each level. When a
caterpillar eats a leaf
 50% of the energy stored in the leaf passes out of the body as waste and/or heat
 40% is used for the caterpillar to survive
 Only 10% is used to increase the size of the caterpillar
So when the robin eats the caterpillar, it is getting only 10% of the caterpillar
This applies to not only energy but also biomass (mass of the living thing) and numbers.
10% Rule states that only 10% of energy, biomass and numbers are available as you go
up each trophic level.
This is often represented pictorially in a pyramid. The three pyramids are essentially similar.
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Energy Pyramid





Every time an organism eats, it obtains energy from its food
So energy is transferred from the 1st trophic level to the 2nd trophic level to the 3rd
trophic level and so on.
Some of this energy is lost along the way during an organism’s metabolism and as heat
This energy can be measured in kilocalories (kcal)
Energy pyramid: picture showing how much energy is transferred to the different
trophic levels in a food chain
Trophic Level
Energy Available
4th
Tertiary
consumers
10 kcal/m2/year
3rd
Secondary
consumers
100 kcal/m2/year
2nd
Primary
consumers
1000 kcal/m2/year
10,000
kcal/m2/year
1st
Producers
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1. In the pyramid of energy, which trophic level contains highest amount of energy?
________________, numbers __________________________, biomass _______________________________.
2. There are many more ______________________________________ then there are secondary
consumers.
3. What does the shape of the energy pyramid suggest? ___________________________________________
____________________________________________________________________________________________________________
4. An ecosystem cannot have more than 4-5 trophic levels. Why? ________________________________
____________________________________________________________________________________________________________
5. When you eat lettuce you are a _______________________
6. When you eat a chicken that has eaten a bug that has eaten the lettuce, you are a
_________________________?
7. In this ecosystem, the energy in the leaves (producers) is calculated to be 100, 000 kcal.
How much of that energy are you getting when you eat the lettuce? ______________________
chicken? ______________________,
8. How much energy is the chicken getting when it eats the bug? __________________
Survival and Interaction between and within populations
Habitat: The place where an organism lives out its life
Niche: all the strategies and adaptations a species uses in its environment
o Includes all its interactions with the biotic and abiotic parts of the environment
o Each type of organism occupies its own niche to avoid competition with other types of
organisms
 Two species can share the same habitat but not the same niche
o Example: Ants and bacteria both live in the dirt (habitat) but have different niches.
Ants eat dead insects and bacteria eat dead leaves, dead logs, and animal waste. So
ants and bacteria don’t compete for resources.
Survival Relationships
 Predator-prey: predators are consumers that hunt and eat other organisms called prey
 Symbiosis: relationship in which one species lives on, in, or near another species and
affects its survival
There are 3 types of symbiosis
1. Mutualism: type of symbiosis in which both species benefit
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
Ants living in the tropical acacia trees- trees are protected when ants attack
animals that try to feed on the tree and ants receive nectar and shelter from the
tree.
2. Commensalism: type of symbiosis in which one species benefits and the other species
is neither harmed nor benefited
 Spanish moss grows on the branches of trees. The moss gets a habitat and the tree
gets nothing.
3. Parasitism: type of symbiosis in which one species benefits and the other species is
harmed
 Parasite: organism that harms but does not kill another organism
 Host: organism that is harmed by a parasite
 Ticks feed on dogs, people, etc. The ticks get food (blood) and the hosts lose blood
and can be infected with disease.
For each of the statements below, state if True or False
_______________ A habitat is the role a species plays in a community.
_______________ Habitats may change.
_______________ A niche is the place where an organism lives its life.
_______________ A habitat can include only one niche.
_______________ A species’ niche includes how the species meets its needs for food and shelter.
_______________ The centipedes and worms that live under a certain log occupy the same habitat
but have different niches.
_______________It is an advantage for two species to share the same niche.
_______________ Competition between two species is reduced when the species have different
niches.
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Period ___
Name __________________________________________________Date ________________
Deer: Predation or Starvation
Introduction:
In 1970 the deer population of an island forest reserve about 518
square
kilometers in size was about 2000 animals. Although the island had excellent vegetation for feeding,
the food supply obviously had limits. Thus the forest management personnel feared that overgrazing
might lead to mass starvation. Since the area was too remote for hunters, the wildlife service decided
to bring in natural predators to control the deer population. It was hoped that natural predation
would keep the deer population from becoming too large and also increase the deer quality (or
health), as predators often eliminate the weaker members of the herd. In 1971, ten wolves were flown
into the island.
Procedure:
The results of this program are shown in the following table. The Population Change is the number of
deer born minus the number of deer that died during that year. Fill out the last column for each year
(the first has been calculated for you).
Year
Wolf
Population
Deer
Population
Deer Offspring
Predation
Starvation
Deer
Population
Change
1971
10
2,000
800
400
100
+300
1972
12
2,300
920
480
240
1973
16
2,500
1,000
640
500
1974
22
2.360
944
880
180
1975
28
2,224
996
1,120
26
1976
24
2,094
836
960
2
1977
21
1,968
788
840
0
1978
18
1,916
766
720
0
1979
19
1,952
780
760
0
1980
19
1,972
790
760
0
1. Graph the deer and wolf populations on the graph below. Use one color to show deer
populations and another color to show wolf populations.
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Analysis
1. Describe what happened to the deer and wolf populations between 1971 and 1980.
2. What do you think would have happened to the deer on the island had wolves NOT been
introduced?
3. Most biology textbooks describe that predators and prey exist in a balance. Some scientists
have criticized this “balance of nature” hypothesis because it suggests a relationship between
predators and prey that is good and necessary. Opponents of this hypothesis propose the
following questions:




Why is death by predators more natural or "right" then death by starvation?
How does one determine when an ecosystem is in "balance"?
Do predators really kill only the old and sick prey? What evidence is there for this statement?
What is your opinion of the balance of nature hypothesis? Would the deer on the island be
better off, worse off, or about the same without the wolves? Defend your position.
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


Cycles in Nature
There is only a limited amount of resources (water, oxygen, nitrogen, carbon) on the earth
In order to keep these resources available to organisms, they must be recycled after they
are used
Cycle: a process that recycles a resource so that you end up with what you started with
Nitrogen Cycle
1. Nitrogen fixation: Bacteria in the
ground change nitrogen from the
atmosphere (N2) to different nitrogen
compounds
2. These bacteria live in plants and
transfer the nitrogen compounds to the
plants
5. Denitrification: Bacteria change the
nitrogen compounds back to N2 and
release it to the atmosphere
4. Bacteria eat the dead animals and
animal waste and take in the nitrogen
compounds
3. Animals eat the plants and take in the
nitrogen compounds
Bacteria change nitrogen compounds
back to nitrogen and release it into the
atmosphere
Nitrogen in
atmosphere
Bacteria eat
dead animals
Bacteria in roots change
nitrogen to nitrogen
compounds
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Water Cycle
3. Transpiration:
2. Seepage: Water
Plants give off water
to the atmosphere
seeps into the ground
and plants use it
1. Precipitation: Rain and snow fall from the
atmosphere to the earth
2. Runoff: Extra
3. Evaporation of
water runs off the land
to lower-lying bodies of
water
water from the bodies
of water back into the
atmosphere
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Oxygen-Carbon Cycle
1. Carbon dioxide (CO2)
and oxygen (O2) are found
in the atmosphere
2. Plants use CO2 to make
2. Animals and plants use
their own food
(photosynthesis)
the O2 to make energy
(respiration)
3. During photosynthesis, plants
3. During respiration, animals and
release O2 back into the
atmosphere
plants release CO2 back into the
atmosphere
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Answer the following questions:
1. Describe the role of producers in carbon cycle _________________________________________________
____________________________________________________________________________________________________________
2. Describe the role of producers in oxygen cycle. _________________________________________________
____________________________________________________________________________________________________________
3. Which organisms can use nitrogen directly from the atmosphere? ___________________________
4. How does nitrogen return to the atmosphere? __________________________________________________
5. It is said that bacteria is the anchor of the ecosystem. Give two reasons why we cannot
survive without bacteria? _________________________________________________________________________
____________________________________________________________________________________________________________
6. Explain how photosynthesis and cellular respiration is involved in cycling of oxygen and
carbon. _____________________________________________________________________________________________
___________________________________________________________________________________________________________
____________________________________________________________________________________________________________
7. Follow a raindrop through two possible paths through the water cycle, ending as water
vapor in the atmosphere.
Path 1____________________________________________________________________________________________________
____________________________________________________________________________________________________________
Path 2____________________________________________________________________________________________________
____________________________________________________________________________________________________________
8. You are one of the six people chosen to live on a self-contained space station. What
organisms would you take with you? Describe the functions you will need each organism
to perform so you can live there for the next three years when the space shuttle will come
for you.
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Ecology Glossary:
Biology – Chapter 34/35
Honors Biology – Chapter __________
1. Biotic factors: _________________________________________________________________________________
Examples of biotic factors _________________________________________________________________________
2. Abiotic factors: ________________________________________________________________________________
Examples of abiotic factors ________________________________________________________________________
Biology Chapter 35
1. Exponential growth __________________________________________________________________________
____________________________________________________________________________________________________________
2. Carrying capacity __________________________________________________________________________
____________________________________________________________________________________________________________
3. Factors effecting population growth
a. Density dependent factor ____________________________________________________________________
Examples of density dependent factors _____________________________________________________
b. Density independent factors __________________________________________________________________
Examples of density independent factor _____________________________________________________
c. Competition: __________________________________________________________________________________
i. Interspecific competition: Competition with other species Ex wolves
with coyotes
ii. Intraspecific competition: Competition within the species. Ex Wolves
with wolves
Biological Magnification, also called bioaccumulation -- is the process whereby certain
substances such as pesticides or heavy metals move up the food chain. These substances
work their way into rivers or lakes, and are eaten by aquatic organisms such as fish, which
in turn are eaten by large birds, animals or humans. The substances, called bioaccumulants, become concentrated in tissues or internal organs as they move up the chain.
Example: Extensive use of DDT to control mosquitoes resulted in its accumulation in the
biological matter and get concentrate as it moved up the food chain eventually getting to
deleterious levels in the bald eagle (top of the food chain). These resulted in the birds
laying eggs with thin shells that compromised the developmental process and almost
made these birds extinct.
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