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Ecology Review Packet
Living Environment
Name_________________________
Date_________________
Food Web
HW: Ecology Questions ___________________________
Due: ____________________
Words you should know:
Population, heterotroph, stability, herbivore, carbon dioxide, habitat, parasite, food web,
ecosystem, species, carnivores, oxygen, bacteria, community, nutrients, niche, producer,
recycle, energy pyramid, predator, prey, consumer, competition, biodiversity, abiotic, biotic ,
decomposer, carrying capacity, autotrophic, energy, succession, omnivore, interdependence,
tropical rain forest, photosynthesis, limiting factors.
Ecology Review Sheet
A. Organism ---> Population --> Community ---> Ecosystem
Population is all the organisms of one species in an area.
Community is all the living things in an area.
Ecosystem is all of the living and non living things in an area and how they interact.
Biotic: living things, Abiotic: non-living things
Niche: the role an organism plays in its environment. It includes such things as where the
organism is in the food web, its trophic level, climate the organism prefers, time of day organism
feeds, time of year organism reproduces.
B. Types of feeders:
Autotrophs (Producers): Make their own food
Heterotrophs (Consumers): Can not make their own food, need to consume it
Types of heterotrophs: herbivores- plant eaters
Omnivores- plant and meat eaters
Carnivores- meat eaters
C. Food chains/webs/pyramids
1. Trophic Levels: assigned to each organism when following the movement of energy
through an ecosystem.
1st trophic level = producer, 2nd trophic level= primary consumer, 3rd trophic level= secondary
consumer
2. Food Chain: relationships among producers, consumers, and decomposers. Arrows
follow energy transfer
3. Food web: All of the food chains in an area.
a. In order to be stable a food web needs producers, consumers, and decomposers.
4. Energy pyramid: shows energy transfer as you go up trophic levels. As you move up the
pyramid the amount of energy and the amount of biomass decreases.
5. The sun is the ultimate source of energy in an ecosystem.
D. Symbiosis- a close long term association between 2 or more species. There are 3 types
1. Parasitism (+, -): Ex: tape worm in a dog
2. Mutualism (+, +): Ex: birds that eat the scraps off food out of alligators mouths
3. Commensalism(+, 0): Ex: barnacles live on the sides of whales, does not affect the whale
E. Population Biology
1. Under ideal conditions; unlimited food, absence of disease, lack of predators -->
populations would increase indefinitely. In the real world this is not the case…. Every
area has a carrying capacity or number of organisms of one species that an environment
can support.
2. Carrying Capacity is determined by
Carrying capacity
limiting factors… things such as
predator/prey relationships, parasitism,
population
disease, competition between 2 different
species, competition between the same
species, space, light, mineral
availability, available water, energy,
time
oxygen.
F. Recycling Materials
1. Decomposers are extremely important because they break down dead organisms and
return the nutrients to the soil to be used.
2. Matter that is cycled includes carbon, nitrogen, oxygen, and also water. If this matter was
not cycled we would run out very quickly and not be able to create new life.
G. Ecological Succession
1. Ecosystems evolve and change until they become stable.
2. Pioneer organisms are the first organisms to return after destruction.
3. Climax Community is the stable community that eventually returns after time. Each area
has a different climax community. In NY it is oak and hickory trees while in VA it is beech
and maple trees.
4. Each community starting with pioneer organisms, modify the environment making it less
favorable for itself and more favorable for other species.
H. Stability
1. Stability is determined by biodiversity
2. Increasing biodiversity increases stability. If one organism is wiped out and the area is
very biodiverse chances are there will be another organism there to fill its niche.
3. Ex: lose rabbit --> elk and other herbivores can eat shrubs that the rabbit was eating and
snake can eat mice and other small animals instead of rabbit… if the area is high in
biodiversity.
Ecology Review Questions:
1. The diagram below illustrates the
relationships between organisms in
an ecosystem.
Raccoons
Ducks
Carnivorous fish
Minnows
5. Which sequence best presents the
flow of energy in the cartoon below?
Crayfish
Algae and floating plants
In addition to sunlight, which factor
would need to be added to make this a
stable ecosystem?
(1) predators
(3) decomposers
(2) prey
(4) herbivores
2. Which relationship best describes
the interactions between lettuce and
a rabbit?
(1) predator – prey
(2) producer – consumer
(3) parasite – host
(4) decomposer – scavenger
3. Which statement best describes a
characteristic of an ecosystem?
(1) It must have producers and
consumers but not
decomposers.
(2) It is stable because it has
consumers to recycle energy
(3) It always has two or more
different autotrophs filling the
same niche.
(4) It must have organisms that
carry out autotrophic nutrition.
4. Which type of model provides the
most complete representation of the
feeding relationships within a
community?
(1) a material cycle
(2) a predator – prey association
(3) a food chain
(4) a food web
(1) prey  predator
(2) host  parasite
(3) producer  herbivore
(4) autotroph  carnivore
6. Decomposers are important in the
environment because they?
(1) convert large molecules into
simpler molecules that can
then be recycled.
(2) release heat from large
molecules so that the heat
can be recycled through the
ecosystem
(3) can take in carbon dioxide
and convert it into oxygen
(4) convert molecules of dead
organisms into permanent
biotic parts of an ecosystem
7. Which statement illustrates a
biotic resource interacting with
an abiotic resource?
(1) A rock moves during an
earthquake
(2) A sea turtle transports a
pilot fish to food
(3) A plant absorbs sunlight,
which is used for
photosynthesis.
(4) A wind causes waves to
form on a lake.
10. Cattail plants in freshwater swamps
in New York State are being replaced
by purple loosestrife plants. The two
species have very similar
environmental requirements. This
observation best illustrates
(1) variations within a species
(2) dynamic equilibrium
(3) random recombination
(4) competition between species
8. Decomposition and decay of
organic matter are accomplished
by the action of
(1) green plants
(2) bacteria and fungi
(3) viruses and algae
(4) scavengers
9. Areas with many different niches
will most likely have
(1) large numbers of
organisms that will become
extinct
(2) no organisms that will
become extinct.
(3) little diversity among the
organisms
(4) great diversity among the
organisms
11. In heterotrophs, energy for the life
processes comes from the chemical
change stored in the bonds of
(1) water molecules
(2) oxygen molecules
(3) organic compounds
(4) inorganic compounds
12. The diagram below represents a food web.
Select and record the name of one species in the food web, and explain how its
removal could affect one of the other species in the food web. (1)
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
13. A food web is more stable than a
food chain because a food web
(1) transfers all of the producer
energy to herbivores
(2) reduces the number of niches
in the ecosystem
(3) includes alternative pathways
for energy flow
(4) includes more consumers than
producers.
14. A partial food web is represented in
the diagram below.
X
Letter X most likely represents
1. autotrophs
3. decomposers
2. carnivores
4. parasites
15. In a stable long-existing community
the establishment of a single species
per niche is most directly the result of
1. parasitism
3. competition
2. interbreeding
4. overproduction
16. Vultures, which are classified as
scavengers, are an important part of
an ecosystem because they
1. hunt herbivores, limiting their
populations in an ecosystem
2. feed on dead animals, which
aids in the recycling of
environmental materials
3. cause the decay of dead
organisms, which releases
usable energy to herbivores
and carnivores
4. are the first level in food webs
and make energy available to
all the other organisms in the
web.
17. Which ecological term includes everything represented in the illustration below?
1. ecosystem
2. community
3. population
4. species
18. Identify one abiotic factor that would directly affect the survival of organism A
shown in the diagram below. (1)
A
_______________________________________________
19. In a forest community, a shelf fungus
and a slug live on the side of a
decaying tree trunk. The fungus
digests and absorbs materials from
the tree, while the slug eats algae
growing on the outside of the trunk.
These organisms do not compete
with one another because they
occupy
1. the same habitat, but different
niches
2. the same niche, but different
habitats
3. the same niche and the same
habitat
4. different habitats and different
niches
20. A pond ecosystem is represented in
the diagram below.
Energy for this ecosystem originally
comes from
1. water
3. sunlight
2. consumers
4. plants
21. The graph below shows the growth of two populations of paramecium in the same
culture dish for 14 days.
Which ecological concept is best represented by the graph?
1. recycling
3. competition
2. equilibrium
4. decomposition
Base your answers to questions 22 and 23 on the diagram of a food web below and on
your knowledge of biology.
22. What is the original source of energy for this food web?
1. the chemical bonds in sugar molecules
2. enzymatic reactions
3. the sun
4. chemical reactions of bacteria
23. Which organisms are not shown in this diagram but are essential to a balanced
ecosystem?
1. heterotrophs
2. autotrophs
3. producers
4. decomposers
24. A food pyramid representing
relationships in a pond community is
shown below.
26. The diagram below represents an
energy pyramid.
D
C
D
B
C
A
B
A
The energy of the Sun is made
available to the pond community
through the activities of the organisms
at level
1. A
3. C
2. B
4. D
25.
Birds
Large Fish
Small Fish
Plants
Which statement best describes what
happens in this energy pyramid?
1. More organisms die at higher levels
than at lower levels, resulting in less
mass at higher levels.
2. Energy is lost to the environment at
each level, so less mass can be
supported at each higher level.
3. When organisms die at higher levels,
their remains sink to lower levels,
increasing the mass of lower levels.
4. Organisms decay at each level, and
thus less mass can be supported at
succeeding higher levels.
Which organisms would most likely be
found at level A?
1. birds
3. mammals
2. worms
4. algae
27. Organisms that eat cows obtain less
energy from the cows than the cows
obtain from the plants they eat because
the cows
1. pass on most of the energy to
their offspring
2. convert solar energy to food
3. store all their energy in milk
4. use energy for their own
metabolism
28. In an ecosystem, which component is not
recycled?
1. water
3. oxygen
2. energy
4. carbon
29. In an ecosystem, nutrients would be
recycled if they were transferred
directly from herbivores to carnivores to
1. hosts
3. decomposers
2. prey
4. autotrophs
30. Which statement best describes
what happens to energy and
molecules in a stable ecosystem?
1. Both energy and molecules are
recycled in an ecosystem
2. Neither energy nor molecules are
recycled in an ecosystem.
3. Energy is recycled and molecules
are continuously added to the
ecosystem
4. Energy is continuously added to
the ecosystem and molecules are
recyled
31. In an ecosystem, what happens to
the atoms of certain chemical
elements such as carbon, oxygen,
and nitrogen?
1. They move into and out of
living systems
2. They are never found in living
systems
3. They move out of living
systems and never return
4. They move into living systems
and remain there
Base your answers to questions 32 though 35 on the energy pyramid below and on your
knowledge of biology.
Level D
Level C
Level B
Level A
32. Energy from nutrients is transferred to ATP in
1. Level A, only
3. Levels B, C, and D, only
2. Levels B and C, only
4. Levels A, B, C, and D
33. The greatest amount of available energy is transferred from level
a. A to level B
3. B to level A
b. A to level C
4. D to level A
34. Which energy levels could contain carnivores?
a. A and B
3. C and D
b. B and C
4. D and A
35. In a community where grass, cats, insects and mice are found, which of these
organisms would fill level A? (1)
_____________________________________________________________
36. One biotic factor that limits the
carrying capacity of any habitat is the
1. availability of water
2. level of atmospheric oxygen
3. activity of decomposers
4. amount of soil erosion
37. An environment can support only as
many organisms as the available
energy, minerals, and oxygen will
allow. Which term is best described
by this statement?
1. biological feedback
2. carrying capacity
3. homeostatic control
4. biological diversity
38. Monocystis is an organism that feeds
on the sperm cells of earthworms. The
activities of Monocystis eventually
causes the infected earthworm to
become sterile. The relationship
between the earthworm and
Monocystis is classified as
(1) Host – parasite
(2) Predator – prey
(3) Producer – consumer
(4) Scavenger – decomposer
39. Increased efforts to conserve areas
such as rainforests are necessary in
order to
(1) protect biodiversity
(2) promote extinction of species
(3) exploit finite resources
(4) increase industrialization
40. An ecosystem will most likely remain
stable if
(1) it has more predators than prey
(2) it has a high level of biodiversity
(3) biotic factors decrease
(4) finite resources decrease
41. The size of a mouse population in a
natural ecosystem tends to remain
relatively constant due to
1. the carrying capacity of the
environment
2. the lack of natural predators
3. cycling of energy
4. increased numbers of
decomposers
42. The carrying capacity of a given
environment is least dependent upon
1. recycling of materials
2. the available energy
3. the availability of food and
water
4. daily temperature fluctuations
43. The chart below shows the
environmental functions that some
organisms perform in a stable
ecosystem.
Environmental
Performed By
Functions
Pollination
Bees, bats
Biodegradation
Microorganisms
Soil aeration
Earthworms
Recycling of atoms
Soil bacteria
CO2 – O2 exchange
Plants
Water storage
Plants
How would a decrease in the number of
organisms that perform these functions
most likely affect the ecosystem?
(1) the interactions between other
organisms would stop immediately
(2) the functions carried out by these
organisms would no longer be
necessary
(3) the ecosystem would remain stable
(4) the ecosystem would become less
stable
44. Which condition would cause an
ecosystem to become unstable?
(1) only heterotrophic organisms
remain after a change in the
environment.
(2) a slight increase in the number
of heterotrophic and autotrophic
organisms occurs
(3) a variety of nonliving factors are
used by the living factors
(4) biotic and abiotic resources
interact
Base your answer to question 45 on the graph
below and on your knowledge of biology.
45. If the environment were to change
dramatically or a new type of plant disease
were to break out, which plant type would
most likely survive?
(1) wild wheat
(3) wild corn
(2) domestic wheat
(4) domestic corn
46. The widest variety of genetic material
that can be used by humans for future
agricultural or medical research would
most likely be found in
(1) a large field of genetically
engineered crop
(2) an ecosystem having significant
biodiversity
(3) a forest that is planted and
maintained by a forest service
(4) areas that contain only one or two
species.
47. In an ecosystem, the presence of many
different species is critical for the
survival of some forms of life when
(1) ecosystems remain stable over long
periods of time
(2) significant changes occur in the
ecosystem
(3) natural selection does not occur
(4) the finite resources of Earth
increase
48. Which ecosystem has a better chance
of surviving when environmental
conditions change over a long period of
time?
(1) one with a great deal of genetic
diversity
(2) one with plants and animals but no
bacteria
(3) one with animals and bacteria but
no plants
(4) one with little or no genetic diversity
49. What would most likely occur after an
ecosystem is disrupted by fire?
(1) the ecosystem would eventually
return to its original state
(2) the ecosystem would return to its
previous state immediately
(3) the ecosystem would evolve into a
new ecosystem that is totally
different from the original
(4) the ecosystem would become an
ever-changing environment with no
stability.
50. Compared to a natural forest, the
wheat field of a farmer lacks
(1) heterotrophs
(2) significant biodiversity
(3) autotrophs
(4) stored energy
51. For many decades, certain areas of
New York State have remained as
hardwood forests containing
predominantly oak and hickory trees.
These forested areas will most likely
(1) remain indefinitely and not affected
by environmental influences
(2) reach maturity and change in the
near future
(3) be destroyed by environmental
changes and never return to their
present forms
(4) continue in their present forms
unless affected by environmental
factors
52. What will most likely result after a fire
or other natural disaster damages an
ecosystem in a certain area?
(1) The area will remain uninhabited for
an indefinite number of centuries
(2) a stable ecosystem will be reestablished after one year
(3) an ecosystem similar to the original
one will eventually be re-established if
the climate is stable
(4) the stable ecosystem that becomes
re-established in the area will be
different from the original
53. A new island formed by volcanic action
may eventually come populated with
biotic communities as a result of
(1) a decrease in the amount of organic
material present
(2) decreased levels of carbon dioxide
in the area
(3) the lack of abiotic factors in the area
(4) the process of ecological
succession
54. Which statement concerning
ecosystems is correct?
(1) Stable ecosystems that are
changed by natural disaster will
slowly recover and may again
become stable if left alone for a
long period of time
(2) Competition does not influence the
number of organisms that live in
ecosystems
(3) Climatic change is the principal
cause of habitat destruction in
ecosystems in the last fifty years
(4) Stable ecosystems, once changed
by natural disaster, will never
recover and become stable again,
even if left alone for a long period of
time.
55. Events that occur in four different ecosystems are shown in the chart below.
Ecosystem A
Events
A severe ice storm occurs during the winter
A
damaging trees and shrubs. No ice storms
occur for the next 20 years
A severe drought causes most of the leaves to
B
fall from the trees during a single summer.
There are no serious droughts for the next 20
years
An island with a dense shrub population
C
becomes submerged for 3 years. When the
river water lowers, the island does not become
submerged for the next 20 years.
A fire burns through a large grassy area.
D
Fires do not occur in the area for the next 20
years.
Which ecosystem would most likely require the most time for ecological succession to restore it
to its original state?
(1) A
(3) C
(2) B
(4) D
56. The diagram below shows changes that might occur over time after a fire in a forest area.
Which statement is most closely related to the events shown in the diagram?
(1) The lack of animals in an altered ecosystem speeds natural disasters
(2) Abrupt changes in an ecosystem only result from human activities.
(3) Stable ecosystems never become established after a natural disaster
(4) An abrupt environmental change can cause a long-term gradual change in an
ecosystem