7th Grade Science
Populations and Ecosystems
Test Review
1. Circle which of the following are learned behaviors that an animal could use to protect itself.
 Hair keeps them warm in cold weather
 Roll in the mud to keep bugs from biting them
 Keen sense of sight to spot predators
 White fur to camouflage themselves in snow
 Chimps use a large stick as a weapon
2. Circle which of the following is an inherited behavior (an animal is born with it).
 Newborn babies can swim
 Spiders know how to build a web
 Fish swim upstream to mate
 Fish leave salt water and return to fresh water
 Chimps use tools to get termites out of their mounds for food
3. Name some biotic (living) components of a desert.
Lizards, snakes, cactus, scorpion
4. Name some abiotic (nonliving) components of a desert.
Sand, heat, sun, rocks, air
5. Trees, bugs, rocks, and warm temperature all describe a forest (Circle one)
 Climate
population
ecosystem
food chain
6. List some limiting factors that might be absent and allow for a population of rabbits to grow out of
control for a period of time.
No predators, plenty of food, water, and shelter, no diseases, no natural disasters, no human activity
7. When a bee visits a flower to collect nectar, it unknowingly picks up pollen from the flower on its
body, then it travels to another flower to collect more nectar. How does the flower help the bee?
The flower gives the bee food (nectar).
How does the bee help the flower?
He bee pollinates the flowers, carries pollen from one flower to another.
7th Grade Science
Populations and Ecosystems
Test Review
8. Use this data table to answer the question.
Insect Species on Different Trees
Tree
Number of Insects:
Species A
Number of Insects:
Species B
A
542
3
B
7
1098
C
0
763
D
876
5
A scientist examined the numbers of two different species of insects on four different kinds of trees in
the same forest. The results of her examination are shown on the data table. What inference can the
scientist make about the insects?
A.
Species B insects are the main food source for species A insects. B.
Species A and species B insects are very closely related. C.
There are more of species B insects than species A insects in the entire forest. D.
Species A insects prefer different kinds of trees from species B insects. 9. What is the definition of a population?
More than one of the SAME SPECIES living in the same area
10. What is the definition of an ecosystem?
Includes both the living (biotic) and nonliving (abiotic) factors
11. How do the birth rate and death rate compare in a population that is at its carrying capacity?
Birth rate = death rate
12. What probably caused the plant in the picture below to grow the way it did?
It was growing toward a source of light (a window, lamp, the sun).
7th Grade Science
Populations and Ecosystems
Test Review
13. Label the carrying capacity in the graph below.
Carrying Capacity (flat
part of line)
14. What will happen to the predators in a population if its prey population decreases significantly?
The predator population will decrease because they won’t have any food.
15. If a fish population uses plants in the water for shelter and to hide from predators, what will
happen to the fish population if all of the water plants die?
The fish population will decrease because they won’t have any shelter to hide from predators.
16. Three different types of birds eat worms as the main part of their diet. What would happen if the
number of worms decreased significantly due to a drought?
All three bird populations would decrease due to lack of food. The three types of birds would compete
for the worms that are left after the drought.
17. Consider the food web below. What is the relationship between the rabbit and the grass?
The grass is a producer and the rabbit is a consumer. The rabbit eats the grass.
18. Explain how a decrease in foxes would affect the rabbit population.
If foxes decreased, the rabbit population would increase because there wouldn’t be as many foxes to eat
them.
19. Draw a graph that shows the relationship you explained in number 18.
7th Grade Science
Populations and Ecosystems
Test Review
20. If wolves moved into the ecosystem where this food web exists and eat most of the rabbits, explain
what effect this will have on the other organisms in this food web.
If the wolves eat most of the rabbits, then foxes will decrease due to lack of food. Mice will decrease
because foxes will be eating them instead of rabbits. Grass will increase because there won’t be as many
mice or rabbits to eat the grass.
21. Use the organisms below to create a food chain. Which organism goes at the bottom of the chain
and which goes at the top to show the correct flow of energy through the food chain?
 snake
grass
mouse
hawk
Hawk (TOP)

Snake

Mouse

Grass (BOTTOM)
22. Give an example of each of the following from the food web below:
Producer: algae or grass
Secondary Consumer: Snake, Hawk
Primary Consumer: prairie dog, frog
Decomposer: Fungi
23. If a wildfire burned through the ecosystem of the food web in number 22, which organisms would
be most affected immediately after the fire? How would they be affected?
Grass and prairie dog
24. Describe the direction and flow of energy as it passes from one organism to another in a food
chain.
Energy flows from producer to consumer. Only 10% of the energy from one level passes to the next level.
7th Grade Science
Populations and Ecosystems
Test Review
25. Name some organisms that might compete with the fox in the food chain below.
Hawk, Snake, Coyote, Wolf
26. Name some organisms that might be the top predator of their food chain.
Human, bear, hawk, owl, shark, coyote, wolf
27. Which level of the food chain below would have the MOST energy available to it? The LEAST
energy available? MOST= producer LEAST= tertiary consumer
28. What does this graph show about the relationship between predator and prey?
When prey increases so does predator. When prey decreases so does predator. They have a very
close relationship and depend upon each other greatly.
29. What is the main source of all energy in an ecosystem? THE SUN
7th Grade Science
Populations and Ecosystems
Test Review
30. Identify a producer, consumer, and decomposer in the ecosystem pictured below.
Producer: algae, tree, grass, bushes
Consumer: plankton, snail, frog, insects, kangaroo, termites, bird, fish
Decomposer: bacteria, fungi (mushrooms)
31. Explain how energy would move from the Sun throughout this ecosystem.
Energy would move from the Sun to the Producers (algae, trees, grass, bushes) to the Consumers
(snails, insects, plankton, termites, kangaroo, frogs, bird, fish) and then to the Decomposers (bacteria
and fungi when the living organisms die.