Science 7 Change Over Time Unit Test Review
1.What is evolution?
2.Which of these scenarios is an example of natural selection?
A. Farmers crossbreed two types of cows to produce a breed of cow that has highquality beef and can tolerate a hot climate.
B. Dogs of the same breed and having a desirable coat color are bred with one
another to produce more puppies with that same coat color.
C. Giraffes with longer necks survive a dry season by eating leaves from the tops of
trees. Those giraffes breed more successfully that year.
D. People capture yellow fish from a pond and breed only the most attractive
individuals. This eventually results in fancy pet goldfish.
3.A species of rodent lives in a moist forest climate. Over time, the climate becomes drier and more desert-like.
Which of these adaptations would most likely improve the chances that the rodent species could
survive as its environment changes?
A. having dark hair and small ears
B. living above ground in damp areas
C. being able to eat only one type of berry
D. being able to eat plants that survive in a dry environment
4.Which of these statements best describes what Charles Darwin observed on the Galapagos Islands?
A.
B.
C.
D.
The finch population on each island was unique.
The finches on the islands ate seeds and nuts but no insects.
The finches on the islands were the same as the finches in Ecuador.
The finches could produce offspring only with finches from other islands.
5.What is selective breeding?
6.The diagram below shows the changes over time in a population of mice in the wild after a population of
hawks has moved into their environment. The white and dark mice differ only in color.
Which statement is the most likely explanation for why the mouse population changed over time?
A. The white mice are able to reproduce more successfully than the dark mice do.
B. The hawks eat more dark mice than white mice because the dark mice taste
better.
C. The hawks eat more white mice than dark mice because they can see the white
mice more easily.
D. The hawks eat more dark mice than white mice, because they can see the dark
mice more easily.
7.What is a population?
8.Charles Darwin studied the finches of the Galapagos Islands and found that their beaks vary in shape and
size.
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Darwin found that the finches that ate mostly insects had long, narrow beaks. Finches that ate
mostly seeds had shorter, broad beaks to crush seeds. Which statement below best describes how
natural selection resulted in the four types of finches shown above?
A. The narrow-beaked finches came first, and evolved into the broad-beaked finches
through a series of natural mutations.
B. The residents of the Galapagos Islands selectively bred together finches having
the traits that they wanted them to have.
C. The broad-beaked finches wore down their beaks digging for insects and passed
these narrower beaks on to their offspring.
D. Over time, the finches that were born with beaks better suited to the available
food supply in their habitats survived and reproduced.
9.Which of these describes a likely reason why a species would become extinct after a major environmental
change?
A. The environmental changes mean fewer predators are around.
B. There are more homes for the species in the changed environment.
C. The change in the environment opens new resources with less competition.
D. There are not enough members of the species born with a trait necessary to
survive in the new environment.
10.Consider the following two finches.
Finch 1:
Finch 2:
Which inference is best supported by these images? Assume that each finch comes from a large
population of similar finches in its particular environment. (Hint: Step 1. Recall what you know about
natural selection. Step 2. Analyze the different characteristics of the two finches and how they may
have evolved due to natural selection.)
A. Finch 1 lives in an environment that is significantly colder and wetter than the
environment in which Finch 2 lives.
B. Finch 1 lives in an environment that is significantly warmer and drier than the
environment in which Finch 2 lives.
C. Finch 1 lives in an environment with many small insects and few seeds; Finch 2
lives in an environment with few insects and many seeds with hard shells.
D. Finch 1 lives in an environment with few insects and many seeds with hard shells;
Finch 2 lives in an environment with many small insects and few seeds.
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11.Which of these scenarios is an example of selective breeding?
A. Goats that have the ability to climb steep cliffs are better able to escape predators.
B. Giraffes having longer necks survive a dry season by eating leaves from the tops
of trees. Those giraffes breed more successfully that year.
C. Dogs of the same breed and having a desirable coat color are bred with one
another to produce more puppies with that same coat color.
D. Green grasshoppers are eaten by birds less often than brown grasshoppers in a
lush, grassy habitat. Eventually, most of the grasshoppers in the population are
green.
12.Which is the best example of an animal responding to an external stimulus?
A. a caterpillar turning into a butterfly
B. a horse eating hay
C. a dog drinking water
D. a cat scratching its belly
13.Malik tripped and fell over a branch as he was hiking in the woods. He caught himself and avoided falling.
Which best describes how his body responded to keep him from falling? (Hint: Step 1. Recall which
body system helps you act quickly to stimuli. Step 2. Recall how this system responds to danger.)
A. His nerves sent electrical signals telling his muscles to move fast.
B. Hormones were released that caused his body to react quickly.
C. His nerves sent electrical signals to make his body sweat.
D. His nerves sent hormones to maintain his balance.
14.Which word best describes the response the seedlings are showing?
A.
B.
C.
D.
taxis
tropism
stimulus
hibernation
15.A fox spots a rabbit in a field. The fox begins to chase the rabbit, and the rabbit runs away. Which best
describes the rabbit’s behavior in response to the stimulus of being chased?
A. It is a tropism.
B. It is a fight-or-flight response.
C. It is a response caused by hunger.
D. It is a response caused by an internal stimulus.
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16.As a frog develops from a tadpole to an adult frog, it goes through changes that are signaled by hormones
within its body. For example, its tail disappears and it grows legs. Which best describes the role of
hormones in changing a tadpole into a frog?
A. The hormones are external stimuli.
B. The hormones are threatening stimuli.
C. The hormones are internal stimuli.
D. The hormones blocks tadpole responses.
17.Dina is relaxing by walking her dog on a warm, sunny afternoon. Dina feels sweaty, and she sees that her
dog is panting. Which is the most likely stimulus causing these responses in both Dina and her
dog?
A. hunger
B. high temperature
C. thirst
D. light from the sun
18.What happens to an animal’s heart rate when it hibernates?
19.Which is an example of an animal responding to an external stimulus?
A. a dog growing a winter coat
B. a cat drinking milk
C. a mouse eating food
D. a person sleeping
20.This is a radish plant. Radishes are called root vegetables because people can eat the root of the radish
plant. But before they can be eaten, radishes need to grow strong and healthy in the soil. What role
in improving the survival of the plant does the root of the radish plant likely have?
21.What is homeostasis?
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22.The diagram shows an important process in the bodies of animals.
What is represented by the label chemical in the diagram?
23. Study the leaves.
What type of tree do these leaves come from? (Hint: Step 1. Examine the structure of the leaves.
Step 2. Recall how to use a dichotomous key to identify objects.)
1. a. The leaves are thin and pointed: go to 2.
1. b. The leaves are flat and wide: go to 3.
2. a. The needles are positioned on both sides of the branch (like the wings of an airplane):
hemlock.
2. b. The needles are bunched in groups of five: white pine.
3. a. There are several small leaves on one leaf stem: white ash.
3. b. There is a single leaf on a single stem: go to 4.
4. a. The leaves are lobed (uneven, pointed edges): go to 5.
4. b. The leaves are plain (no large points on the edges): beech.
5. a. The leaves have more than five lobes: oak.
5. b. The leaves have five or fewer lobes: maple.
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24.Study the leaves.
What type of leaves are shown? (Hint: Step 1. Examine the structure of the leaves. Step 2. Recall
how to use a dichotomous key to identify objects.)
1. a. The leaves are thin and pointed: go to 2.
1. b. The leaves are flat and wide: go to 3.
2. a. The needles are positioned on both sides of the branch (like the wings of an airplane):
hemlock.
2. b. The needles are bunched in groups of five: white pine.
3. a. There are several leaves on one leaf stem: white ash.
3. b. There is a single leaf on a single leaf stem: go to 4.
4. a. The leaves are lobed (uneven, pointed edges): go to 5.
4. b. The leaves are plain (no large points on the edges): beech.
5. a. The leaves have more than five lobes: oak.
5. b. The leaves have five or fewer lobes: maple.
25.Which term describes the number and variety of plants and animals living in an area?
A. natural selection
B. biodiversity
C. ecosystem
D. habitat
Short Answer
26. Give an example of a way in which organisms in a population can vary in terms of behavior. Explain
how this kind of variation within a population can help a species survive in a changing environment.
27. Molly is playing soccer. Explain how Molly’s body maintains homeostasis as she plays soccer.
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