STUDY GUIDE SECTION 18-1
Introduction to Ecology
Name _____________________
Period __________
Date ____________
Multiple Choice-Write the correct letter in the blank.
1. ______ All the robins in an area would be an example of a(n)
a. community
b. population
c. ecosystem
d. biosphere
2. ______ The broadest, most inclusive level of ecological organization is the
a. population
b, community
c. biosphere
d. ecosystem
3. ______ A pond is an example of
a. a population
b. a community
c. a biosphere
d. an ecosystem
4. ______ Ecologists use models to
a. make predictions about the future behavior of an ecosystem.
b. substitute for observations from the natural world.
c. increase the complexity of simple ecosystems.
d. account for the influence of every variable in a real environment.
Short Answer-Answer the following questions in complete sentences.
1. Explain why interdependence is an important theme in ecology. ____________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
2. How does the production of acorns by oak trees affect Lyme disease in humans? _______
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
3. Explain why ecological models commonly have limited applications. ________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
Page 1 of 8
4. How does a population differ from a community? _______________________________
________________________________________________________________________
________________________________________________________________________
5. Explain why the amount of sunlight in an ecosystem is important to the animals that live
in that ecosystem. _________________________________________________________
________________________________________________________________________
________________________________________________________________________
6. Assuming that wolves eat deer, how could a disease that kills a large portion of the wolf
population affect the mice population in a forest ecosystem? _______________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
7. Explain two examples of how the destruction of large areas of tropical rainforests could
have world-wide consequences.
A. _____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
B. _____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
STRUCTURES AND FUNCTIONS The drawings below represent five levels of ecological
organization. In the spaces provided, label the levels and number them 1 to 5, with 1 being
the most inclusive.
Page 2 of 8
STUDY GUIDE SECTION 18-2
Ecology of Organisms
Multiple Choice-Write the correct letter in the blank.
1. ______ One biotic factor that could influence a plant might be
a. the amount of sunlight.
c. carbon dioxide concentration.
b. soil pH.
d. a pollinating insect.
2. ______ People who spend time at high elevations develop more red blood cells, which
helps them obtain oxygen from the “thin air”. This phenomenon is an example of
a. acclimation
b. adaptation
c. migration
d. dormancy
3. _____ An animal that maintains its body temperature within a narrow range even when
the environmental temperature varies is an example of a
a. specialist
b. generalist
c. regulator
d. conformer
4. ______ The role a species plays in its environment is called the species’
a. habitat
b. niche
c. resources
d. tolerance curve
5. ______ An animal that feeds on leaves from only a few species of plants is an example of
a
a. regulator
b. generalist
c. conformer
d. specialist
Short Answer-Answer the following questions in complete sentences.
1. Give three examples of abiotic factors and explain how they might affect a plant:
A. ________________- ___________________________________________________
____________________________________________________________________
B. ________________- ___________________________________________________
_____________________________________________________________________
C. ________________- ___________________________________________________
____________________________________________________________________
2. Explain how migration allows organisms to cope with a changing environment.________
________________________________________________________________________
________________________________________________________________________
Page 3 of 8
3. Explain how a species’ habitat differs from its niche. _____________________________
________________________________________________________________________
________________________________________________________________________
4. Explain why the Virginia opossum is considered a generalist and the koala is considered
a specialist. ______________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
5. Why do different species never occupy exactly the same niche? ____________________
________________________________________________________________________
________________________________________________________________________
6. What are two ways that some organisms can escape from unfavorable environmental
conditions?
A. ____________________________________________________________________
B. ____________________________________________________________________
STRUCTURES AND FUNCTIONS Label the curve in the graph below according to the
type of organism they represent and give a specific example of each type of organism.
Page 4 of 8
STUDY GUIDE SECTION 18-3
Energy Transfers
Multiple Choice-Write the correct letter in the blank.
1. ______The term biomass refers to the
a. weight of the biosphere.
b. organic material in an ecosystem.
c. volume of plants in a community.
d. amount of energy produced through chemosynthesis.
2. ______ A detritivore is an organism that
a. feeds on both producers and consumers.
b. feeds on the “organic waste” of an ecosystem.
c. converts biomass into “organic waste” in an ecosystem.
d. produces carbohydrates by using energy from inorganic molecules.
3. ______ An organism’s position in the sequence of energy transfers in an ecosystem is
know as its
a. trophic level.
c. net productivity.
b. energy level.
d. feeding location.
4. ______ The percentage of energy transferred from one level to another in a food chain is
usually
a. greater than 90%.
c. about 50%.
b. about 75%.
d. less than 20%.
5. ______ Compared to the lowest trophic level, the highest trophic levels contains
a. more individuals.
c. more producers.
b. less energy.
d. fewer carnivores.
Short Answer-Answer the following questions in complete sentences.
1. Rank the following ecosystems in order of their net primary productivity, from lowest to
highest: ______open ocean, _______tropical rain forest, _______desert, _______lake.
2. Why are producers the first trophic level to benefit from the activity of decomposers?___
_________________________________________________________________________
Page 5 of 8
3. Explain three reasons why energy transfer between trophic levels is not 100%
A. ____________________________________________________________________
B. ____________________________________________________________________
C. _____________________________________________________________________
4. List and describe the five types of consumers:
A. __________________- _________________________________________________
B. __________________- _________________________________________________
C. __________________- _________________________________________________
D. __________________- _________________________________________________
E. __________________- _________________________________________________
5. Why are food chains short? _________________________________________________
________________________________________________________________________
6. Explain why the same area can support a greater number of herbivores than carnivores.
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
7. What would happen to the energy flow through an ecosystem if the decomposers were
eliminated? ______________________________________________________________
________________________________________________________________________
________________________________________________________________________
STRUCTURES AND FUNCTIONS The diagram below shows part of a food web. Each arrow
indicates energy passing from one member (the food) to another (the consumer). Only some of
the indicated relationships are possible. Write yes in the spaces corresponding to the possible
relationships, and no in the spaces corresponding to the relationships that are not possible.
Page 6 of 8
STUDY GUIDE SECTION 18-4
Ecosystem Recycling
Multiple Choice-Write the correct letter in the blank.
1. ______ the term groundwater refers to water that
a. exists in lakes and ponds.
c. is found in soil or in underground formations.
b. has fallen to sea level.
d. lies on the surface of the ground after a heavy rain.
2. ______ At least 90% of the water that returns to the atmosphere from terrestrial
ecosystems does so through
a. transpiration in plants
c. sweating in animals.
b. excretion in animals.
d. precipitation.
3. ______ Two sources of carbon dioxide released into the atmosphere in the carbon cycle
are
a. photosynthesis and decomposition.
c. combustion and transpiration.
b. cellular respiration and photosynthesis. d. cellular respiration and combustion.
4. ______ Two components of the nitrogen cycle that produce ammonia are
a. nitrification and denitrification.
c. nitrogen fixation and ammonification.
b. nitrogen fixation and nitrification.
d. ammonification and denitrification.
5. ______ Animals obtain nitrogen
a. through a mutualistic relationship with nitrogen-fixing bacteria.
b. from the proteins and nucleic acids in the organisms they consume.
c. by absorbing nitrates and ammonia from the soil.
d. by absorbing nitrogen gas from the atmosphere.
Short Answer-Answer the following questions in complete sentences.
1. In the space below, draw an outline of the carbon cycle.
Page 7 of 8
2. Describe the role of decomposers in the nitrogen cycle: ___________________________
________________________________________________________________________
________________________________________________________________________
3. Name three processes in the water cycle, and state whether each process removes water
from the atmosphere or returns it to the atmosphere.
A. _________________________- __________________________________________
B. _________________________- __________________________________________
C. _________________________- __________________________________________
4. A. Where are nitrogen-fixing bacteria found? ___________________________________
B. Explain how these bacteria benefit plants. ___________________________________
________________________________________________________________________
5. Explain the statement “Nutrients cycle, but energy flows”. ________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
STRUCTURES AND FUNCTIONS The diagram below represent the effect of the water,
carbon, and nitrogen cycles on the life of a plant. Identify the process indicated in the three
cycles.
Page 8 of 8