Name _______________________________Class __________________ Date __________________
14 3, 4 and 5
Study Guide A
1. Fill in the blank to complete the equation.
Number of individuals

Area (units 2 )
2. Circle the letter next to the situation that would explain an increase in the population density of a
population of deer.
a. an increase in the number of deer predators
b. a decrease in the area of deer habitat
c. an increase in the area of deer habitat
d. a decrease in the number of deer in the area
Circle the letter of the term that correctly describes the type of
population dispersion.
3. Individual organisms live close together, making it easier for them to find mates and protect each other.
a. clumped dispersion
b. uniform dispersion
c. random dispersion
d. standard dispersion
4. Individuals live at a specific distance from each other to avoid competition for limited resources.
a. clumped dispersion
b. uniform dispersion
c. random dispersion
d. standard dispersion
5. Individuals are spread out in no particular pattern.
a. clumped dispersion
b. uniform dispersion
c. random dispersion
d. standard dispersion
6. An organism’s _____________________ _______________ reflects the way it produces offspring and
helps the population survive.
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Holt McDougal Biology
1
Interactions in Ecosystems
Name ______________________________ Class ___________________ Date __________________
Number of survivors
120
100
80
60
40
20
0
10 20 30 40 50 60 70 80 90 100
Percentage of maximum life span
Look at each of the survivorship curves shown above. Next to the type of
organism described below, write whether it is an example of Type I, Type II, or
Type III survivorship.
_________ 7. Birds, small mammals, and other small animals have a survival rate
that stays about the same from birth to death.
_________ 8. Fish, amphibians, and plants produce large numbers of young. The
young of these organisms have a high death rate.
_________ 9. Lions and other large mammals care for their young. The young of
these organisms have a high survival rate.
10. Population __________________ describes the number of individual
organisms per unit area or volume.
11. Population __________________ describes the way a population is spread out
over
an area.
12. A ____________________ ______________ helps describe the reproductive
strategy of a species
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Holt McDougal Biology
2
Interactions in Ecosystems
Name _______________________________Class __________________ Date __________________
Choose a word from the box below that best completes the sentence.
births
emigration
deaths
immigration
1 . Resources are very abundant in a particular area. Individuals may move
into a population in this area to take advantage of the abundant resources.
The movement of individuals into a population from another area is called ________________.
2. A very cold winter has left many deer in a population hungry and sick.
By the end of the winter, this population will likely decrease because of ________________.
3. A deer population experiences growth when the rate of reproduction increases. This change in
population size is due to _________________.
4. Humans build new houses in a territory inhabited by deer. Many members of the deer population move
away and join herds in other areas. This movement of individuals out of a population is called
_________________.
Fill in the blank with a word that best completes the sentence.
5. When plenty of resources are available, a population is likely to __________.
6. When few resources are available, a population is likely to __________.
7.Draw a curve in each space to show the type of population growth described.
Rapid
population
growth when
resources are
abundant
Logistic growth
Exponential growth
Slow growth is
followed by
exponential
growth, then the
size of the
population
stabilizes
8.____________ growth shows a carrying capacity.
9. ____________ growth is at risk for a population crash because of resource
depletion.
12. Individual organisms ____________________ when they move into a population.
13. A limiting factor that is affected by population density is a __________________________________.
14. Individual organisms ____________________ when they move out of a population.
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Holt McDougal Biology
3
Interactions in Ecosystems
Name _______________________________Class __________________ Date __________________
1. Ecological succession is the sequence of ________________ that regenerate a damaged community or
create a new community in an area that was previously uninhabited.
2. Below are statements that describe the four main steps of primary succession.
Write a number from 1 through 4 beside each step, to indicate the order in which these steps take place.
_____ a. Seeds of flowers and shrubs grow into plants that offer habitat for small animals and continue
to build soil.
_____ b. Lichen and mosses break down rock. As they die, their decayed bodies begin to build soil.
_____ c. Wind, rain and ice begin to break down rock surfaces.
_____ d. Larger plants and animals move into the area as the soil layer gets thicker.
3. Below are statements that describe the four main steps of
secondary succession.
Write a number from 1 through 4 beside each step, to indicate the order in which these steps take place.
_____ a.
_____ b.
_____ c.
_____ d.
Evergreen trees grow larger and hardwood trees begin to grow.
Weed and wildflower seeds take root in the soil.
A disturbance destroys a community.
Shrub and evergreen tree seedlings begin to grow.
Vocabulary Check
Fill in the blank with the word or phrase that best completes the sentence.
4. Ecological succession that begins in an area without an existing community
of plants is called __________________________.
5. Ecological succession that begins in an area that already had an existing community of plants and
animals is called ____________________________.
6. The first species to appear in a previously uninhabited area are called ___________________________.
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Holt McDougal Biology
3
Interactions in Ecosystems