Name _______________________________________________ Per _____________ Date_________________
Animal Populations Test Review
Vocabulary-Define the following words and be able to recognize examples of each.
Population-group of individuals of the same species living in the same area
Population density-amount of organisms per unit area
Limiting factor-factors that limit the number of individuals in a population in an area
Density dependent limiting factors-limiting factors that depend on the number of individuals in an area
Density independent limiting factors- limiting factors that do not depend on the number of individuals in an area
Carrying capacity-the number of individuals an area can support based on the available resources
Immigration-individuals moving into an area
Emigration- individuals moving out of an area
Birth rate-rate at which individuals reproduce
Death rate- rate at which individuals die
R-Strategist-short lives and produces large number of offspring
K-Strategist-long lives and produces few offspring
Answer the following.
1. List five factors that would cause a population to grow.
Adequate food, water, shelter, limited predators, good weather
2. What happens when resources in a population become less available?
The population will begin to die and eventually reach carrying capacity
3. What happens when a population grows larger than the carrying capacity of the environment?
Individuals will start to die until the population levels off at carrying capacity
4. List three factors that will reduce competition within a population.
Adequate food, water, shelter, fewer individuals, fewer predators
Bats are often feared but they benefit ecosystems both economically and ecologically. One bat can
consume about 1200 mosquito size animals in one hour. Bat colonies consist of thousands of bats
which can eat millions of insects throughout the summer. This is beneficial to the economy because
many of these insects are pests which destroy crops and spread disease. Some bat colonies are in
danger because they have contracted Bat White Nose Syndrome which is a fungus that kills bats.
5. Is Bat White Nose Syndrome a density dependent limiting factor or a density independent limiting factor?
Explain.
The syndrome is a density dependent factor because the disease will spread faster when there are more
individuals.
6. How will the death of bats affect the economy and ecology or an area?
Ecologically there will be fewer bats to eat all the insects so the insect population will increase. If there are
more insects the economy will be harmed because the crop production will decrease.
7. Our area is growing rapidly. How does this impact the carrying capacity of our surrounding area? Will
populations of wild animals increase or decrease as we continue to expand?
The carrying capacity of our area will be reduced because there is less area to support the population of wild
animals.
8. A farming community in Texas covers 24 square kilometers. There are 840 individuals who live within the
town limits. What is the population density of this community?
840/24 = 35 individuals per square kilometers
9. A biologist originally marked 30 Brown Pelicans on Galveston Island. Over a six month long period
150 Brown Pelicans were captured. Of those 150, 45 were found to have tags. Based on this
information, what is the estimated population size of the Brown Pelicans on Galveston Island?
Population Estimate = (Total Number Captured) X (Number Marked)
(Total Number Captured With Mark)
Population Estimate = (150) X (30) = 100 Brown Pelicans
(45)
Scientists recorded this data that shows populations of snakes and mice found in an experimental field.
Mice were introduced to the filed, and their numbers allowed stabilizing and reaching their carrying
capacity with no predation.
A breeding pair of snakes was introduced in 1960. No immigration or emigration occurred.
Year
1960
1970
1980
1992
2000
2010
Snake and Mouse Populations in an Experimental Field
# of Snakes
Mice Born per 1000
Mice Died per 1000
2
1000
200
10
8000
300
30
400
400
15
600
550
14
620
600
15
640
580
10. What is the relationship between the mouse population size and the snake population size?
The mouse population decreased as the snake population increased.
11. What is the carrying capacity for the snake population?
Approximately 15 snakes
12. When did the mice experience zero population growth?
Zero population growth was reached in 1980 when births equaled deaths.
The formula for calculating growth rate is: Growth Rate = (Births) - (Deaths)
13. Calculate the growth rate of mice in 1970.
Growth Rate = 8000 - 300 = 7700 mice born per 1000 mice
14. Are the snakes an invasive species? Explain.
No. The snakes were not native to the area but the helped control the mouse population without eliminating
all of the mice.
15. Why is it important to do population counts? Give an example in your explanation.
Population counts help us monitor species to understand how healthy an ecosystem is. The process is very
important in helping protect endangered species such as tigers so we know how many there are and how they
are interacting.
16. Explain how limiting factors control population growth. Include an example of a density dependent and a
density independent factor in your explanation.
Limiting factors help control populations because they actually limit growth in some way. Food is an example
of a density dependent factor because the more individuals there are the less food is available. Natural
disasters such as forest fires are density independent limiting factors because they will limit however many
individuals there are.
17. Briefly describe each of the following methods used to count populations.
a. Capture mark recapture-capture individual, mark in some manner, release and recapture…use formula
to calculate total population
b. Transects-count individuals along a straight line in an area… use formula to calculate total population
c. Quadrat-toss square in an area, count individuals in square… use formula to calculate total population
d. Camera Census-use automatic cameras to capture images of individuals in an area and use formula to
calculate total population