7th Grade Science Sample Assessment Items
S7L5a-c.
Scientists find a fossil (Fossil A) in a deep layer of sedimentary rock. They determine that Fossil
A is the remains of a species never seen before. A few years later, other scientists discover a
similar fossil (Fossil B) in a layer of sedimentary rock closer to Earth’s surface. Fossil A and
Fossil B share some characteristics, but it is determined that they are not closely related and
that Fossil B is a different species. One hundred years later, scientists discover another similar
fossil (Fossil C) in a layer of sedimentary rock between those in which Fossils A and B were
found. Upon examining all three fossils, scientists reach the conclusion that all three fossils
represent the same species. They determine that Fossil B (found in the shallowest rock layer)
evolved from Fossil C (found in an intermediary layer), which evolved from Fossil A (found in the
deepest rock layer).
Which statement BEST describes this scenario?
A. Very little can be learned about the evolution of a species by examining the fossil record.
B. Early fossil researchers did not understand the information provided by the fossil record.
C. The fossil record provides trace evidence for the long history of changing life forms.
D. Theories about the fossil record do not change based on finding new evidence.
Explanation of Correct Answer from Study/Resource Guide: The correct answer is choice (C)
The fossil record provides trace evidence for the long history of changing life forms. Scientists
have learned a lot about the evolution of living things by studying fossils and where they appear
in sedimentary rock layers. Choice (A) is incorrect because the fossil record has revealed
significant evidence about the evolution of species. Choice (B) is incorrect. Early fossil
researchers understood the fossil record as well as possible, given the information they had at
the time. Scientific knowledge changes when new information is discovered. Choice (D) is
incorrect because our understanding of the fossil record has changed a lot based on
examination of new evidence.
Which of the following BEST describes the effect that natural selection might have on a species
over time? [DOK 2]
A. The fur color of a species will always change over time, because of natural selection.
B. Predator species will always increase due to natural selection, while prey species will
always die out.
C. Members of a species with traits that allow them to survive and reproduce in an
environment will increase in population, while those without those traits will die.
D. Bigger members of a species always have an advantage over smaller members.
Therefore, over time, a species will eventually include larger organisms only.
Explanation of Correct Answer from Resource/Study Guide: The correct answer is choice (C)
Members of a species with traits that allow them to survive and reproduce in an environment will
increase in population, while those without those traits will die. Eventually, unsuitable traits will
disappear from a species. This is how natural selection affects species. Choice (A) is incorrect
because fur color will change only if it is an unsuitable trait for the environment and affects the
organism’s survival and/or reproduction. Choice (D) is incorrect because larger organisms do
not always have better survival chances, compared with smaller organisms. Choice (B) is
incorrect because there are more factors that affect populations of predators and prey than
natural selection alone.
7th Grade Science Sample Assessment Items
S7L5a-c.
The walking catfish is a species of fish that walks on land using its pectoral fins. During drought
conditions, when there is little water in its habitat, the walking catfish can use its pectoral fins to
get to areas with water.
Which of these will MOST LIKELY happen to a population of walking catfish over time if all
nearby aquatic environments dry up permanently? [DOK 3]
A. Walking catfish with small pectoral fins are more likely to survive a trip to distant areas of
water. The population is likely to evolve to have smaller pectoral fins.
B. Walking catfish with large pectoral fins are more likely to survive a trip to distant areas of
water. The population is likely to evolve to have larger pectoral fins.
C. Walking catfish with large pectoral fins and those with small pectoral fins are equally likely
to survive a trip to distant areas of water. Both types survive, so evolution is unlikely to
occur.
D. Walking catfish with large pectoral fins and those with small pectoral fins are equally likely
to not survive the trip to distant areas of water. Both types of catfish will then become
extinct.
Explanation of Correct Answer from Study/Resource Guide: The correct answer is choice (B)
Walking catfish with large pectoral fins are more likely to survive a trip to distant areas of water.
The population is likely to evolve to have larger pectoral fins. Larger pectoral fins are an
individual characteristic that make it more likely that a walking catfish will survive a trip to a
distant body of water. Natural selection will favor the catfish with larger pectoral fins, as more of
them survive. Choice (A) is incorrect because smaller pectoral fins make it less likely for the
walking catfish to survive the trip to a distant body of water. Choice (C) is incorrect. A walking
catfish with larger pectoral fins is more likely to travel farther to get to a distant body of water.
Choice (D) is incorrect. A catfish with larger pectoral fins has an individual characteristic that
makes it more likely to survive a trip to a distant body of water.
A science class takes a field trip to a rock formation known for the many fossils it holds. A
student finds a fossil that shows a plant with leaves similar to those of a plant that grows nearby.
The student tells his classmates that the plants must be an ancient species that has not
changed much over time. Which statement BEST describes the student’s claim? [DOK 2]
A. The claim is reasonable because plants do not change over time.
B. The claim is reasonable because fossils are records of things that lived long ago.
C. The claim is not reasonable because plants must change over time.
D. The claim is not reasonable because fossils can be made from recently living organisms.
Explanation of Correct Answer from Study/Resource Guide: The correct answer is choice (B)
The claim is reasonable because fossils are records of things that lived long ago. Since the
fossil and the plant share similar features, it can be assumed that the species that formed the
fossil has not changed greatly over time. Choice (A) is incorrect because the plant has changed
over time but not greatly. Choice (C) is incorrect because the claim is reasonable, the plant has
changed over time, just not much. Choice (D) is incorrect because the claim is reasonable, the
fossil appears to belong to a species that lived long ago.
7th Grade Science Sample Assessment Items
S7L5a-c.
Scientists find fish fossils in Rock Layers B and C
of a canyon. The fossil found in Rock Layer B is
similar to the fossil found in Rock Layer C.
Which conclusion is BEST supported by the order of the layers? [DOK 3]
A. The two fossils are different species, because they are in adjacent layers.
B. The two fossils are the same species, because they are in adjacent layers.
C. The species in Layer C may have evolved from the species in Layer B.
D. The species in Layer B may have evolved from the species in Layer C.
Explanation of Correct Answer from Study/Resource Guide: The correct answer is choice (C)
The species in Layer C may have evolved from the species in Layer B. These fossils
demonstrate gradualism, the theory that states that species gradually change over time.
Because the fossils are found in different layers of sedimentary rock, the newer layer contains
species that may have evolved from older species found in the older layer below it. Choice (A) is
incorrect because being in adjacent layers does not provide enough information to indicate that
they are different species. Choice (B) is incorrect because there is not enough information about
the fossils to know whether they are the same. Choice (D) is incorrect because fossils found in
lower layers of sedimentary stone are usually older than the fossils found in upper layers.
Scientists have collected fossil evidence of an organism that lived on Earth over forty million
years ago. The species was a large-bodied, pig-like mammal with four small legs and smooth,
hairless skin.
Which of these is MOST LIKELY true about this species?
A. It became extinct within one generation.
B. It evolved into another species within one generation.
C. It evolved into another species over many generations.
D. It has remained unchanged over many generations.
Explanation of Correct Answer from the Assessment Guide: The correct answer is choice (C) It
evolved into another species over many generations. Species typically evolve slowly over many
generations. As a species evolves, later generations are sometimes so different from earlier
generations that scientists classify them as different species. Choice (A) is incorrect because it
is unlikely that such complex organisms would disappear completely within a single generation.
Choice (B) is incorrect because it is unlikely that such complex organisms would evolve so
dramatically within a single generation. Choice (D) is incorrect because it is unlikely that over
millions and millions of years a species would not change at all.
7th Grade Science Sample Assessment Items
S7L5a-c.
Fire ants in the southeastern United States were accidentally introduced over seventy years
ago. Stings from fire ants can be deadly to the native fence lizard. Fence lizards that have lived
in areas with fire ants for many generations have longer legs than fence lizards that have not
lived in areas with fire ants until more recently.
Which statement BEST describes how the legs of the fence lizard changed over time? [DOK 3]
A. Over time, fence lizards with longer legs were more likely to survive and passed this trait
on to offspring.
B. Over time, fence lizards stretched their legs to increase leg length and passed this trait on
to their offspring.
C. The lizards of each generation are born without longer legs. They then grow the longer
legs to avoid stepping on the fire ants.
D. The lizards living in areas where fire ants were first introduced used the venom from fire
ants to grow longer legs. The trait for longer legs was then passed on to offspring.
Explanation of Correct Answer from Study/Resource Guide: The correct answer is choice (A)
Over time, fence lizards with longer legs were more likely to survive and passed this trait on to
offspring. Choice (B) is incorrect because leg stretching is not an inherited trait and would not be
passed on to offspring. Choice (C) is incorrect because trying to avoid stepping on ants would
not cause the lizards’ legs to grow longer. Choice (D) is incorrect because the venom did not
directly play a role in the change in leg length.
An insecticide is a chemical that can rid a plant of insects that cause damage to the plant. If the
same insecticide is used for many years, it is likely that it will no longer rid plants of insects.
Which statement BEST explains why insects are no longer harmed by an insecticide that has
been used on the same plants for many years?
A. Over time, plants sprayed with an insecticide develop a resistance to it, which transfers to the
insects when the insects eat the plants.
B. Some insects are born with an ability to avoid harm from an insecticide, and they pass this
ability to their offspring when they mate and reproduce.
C. Some insects are born with an ability to avoid harm from an insecticide, and they pass this
ability to other insects by coming into contact with them.
D. Over time, plants sprayed with an insecticide develop a resistance to it, which transfers to the
insects when the insects lay their eggs on the plants.
Explanation of Correct Answer from the Assessment Guide: The correct answer is choice (B)
Some insects are born with an ability to avoid harm from an insecticide, and they pass this
ability to their offspring when they mate and reproduce. Insects with this ability have an
advantage over insects without this ability; over many generations, more insects with this ability
will survive to reproduce, and more insects without this ability will die before they can reproduce.
Eventually, most of the insects in the population will have the ability to avoid harm from the
insecticide. Choices (A), (C), and (D) are incorrect because organisms cannot pass a trait such
as resistance to other organisms in these ways.
7th Grade Science Sample Assessment Items
S7L5a-c.
A student read about the peppered moth, a species whose population changed over a period of
time. Before the Industrial Revolution, dark-colored moths were rare. During the Industrial
Revolution, however, the population of dark-colored moths greatly increased. The student
thought that the reason for the increase in dark-colored moths was soot covering the wings of
the light-colored moths. She thought this coloring was then passed on to the offspring of the
light-colored moths.
Which statement should be used to explain to the student the correct reason for how this
population changed over time? [DOK 2]
A. The dark-colored moths could fly faster than the light-colored moths.
B. The dark-colored moths found food more easily than the light-colored moths.
C. The dark-colored moths hid more easily from predators than the light-colored moths.
D. The dark-colored moths were able to produce more eggs than the light-colored moths.
Explanation of Correct Answer from the Assessment Guide: The correct answer is choice (C)
The dark-colored moths hid more easily from predators than the light-colored moths. Soot
produced by factories during the Industrial Revolution darkened the trees where the moths lived.
Dark-colored moths blended into the darkened trees, so predators were less likely to spot and
eat them. Over time, more dark-colored moths survived to reproduce and pass on their traits,
including their dark coloring, to their offspring. Choices (A), (B), and (D) are incorrect because a
moth’s coloring does not affect its ability to fly, find food, or produce eggs.
What did Darwin observe about finches in the Galapagos Islands?
A. Their beaks had adapted to the foods they ate.*
B. They had identical genotypes in all locations.
C. They had identical phenotypes in all locations.
D. Their feathers had adapted to match their environment
A species of finch has been studied on one of the geographically isolated Galapagos Islands for
many years. Since the island is small, the lineage of every bird for several generations is known.
This allows a family tree of each bird to be developed. Some family groups have survived and
others have died out. The group that survive probably have _______.
A. interbred with other species
B. been attacked by more predators
C. found new places on the island to live
D. inherited some advantageous variations*
7th Grade Science Sample Assessment Items
S7L5a-c.
Which information would best help scientists verify the relationships among the organisms
shown above?
A. The organisms’ DNA sequences*
B. The organisms’ population sizes
C. The organisms’ migratory patterns
D. The organisms’ nutritional requirements
Which type of Drosophila probably changed the least
over time?
A. Drosophila willistoni
B. Drosophila melanogaster*
C. Drosophila equinoxialis equinoxialis
D. Drosophila equinoxialis caribbensis
7th Grade Science Sample Assessment Items
S7L5a-c.
All the organisms shown above belong to the Phylum Chordata.
The structural similarity in the organisms suggests that ________.
A. chordates have common ancestors*
B. the humerus is the same size in all chordates
C. only animals that walk on 4 legs need the humerus
D. the humerus is attached to the skeleton by immovable joints
Which of the following most likely supports how giraffes evolved long necks?
A. More long-necked giraffes survived to pass on their genes.*
B. More short-necked giraffes survived to pass on their genes.
C. Short-necked giraffes grew longer necks to reach higher leaves.
D. Short-necked giraffes modified their diets to evolve into a new species.
An early biological theory stated that a change in a population can occur when organisms with
favorable variations for a particular environment survive and pass these variations on to the next
generation. This theory is better known as the Theory of ________.
A. Natural Selection*
B. Punctuated Selection
C. Acquired Characteristics
D. Variation and Adaptation
Fossils of animals the size of goats were dated at 5 million years old. Similarly, fossils of larger
animals were dated at 3 million years old. Both animals were similar in body structure to today’s
horses. Using these data, which inference can scientists make?
A. The animals became smaller with time.
B. Today's horses are faster than these animals were.
C. The animals could have been ancestors of today's horses.*
D. Today's horses and these animals probably lived together at some time in the past.
7th Grade Science Sample Assessment Items
S7L5a-c.
Charles Darwin proposed his theory of evolution based on
observations of nature. Which observation that contributed
to his theory is illustrated by this population of beetles?
A Environmental resources are limited.
B Populations remain stable over time.
C Individuals within a population may vary widely.*
D Species produce more offspring than can survive.
The presence of an animal fossil in a rock gives evidence of —
A. how many babies the animal had
B. exactly when the animal was born
C. the time period the animal lived in*
D. what hunting behaviors the animal used
According to this fossil record chart, trilobites
probably lived in what ancient environment?
A. Shallow seas*
B. Mountaintops
C. Freshwater lakes
D. Terrestrial forests
7th Grade Science Sample Assessment Items
S7L5a-c.
Look at the diagram to the right. If the
organisms shown come from a common
ancestor, why are their structures different?
The drawings to the right show skulls
of three modern animals and their ancestors.
What conclusion can be drawn about the
relationship between the three animals?
At one time, there were bright colored termites and dark colored termites. However, after
several generations, termite populations now consist almost entirely of dark colored members.
Identify the concept and explain how it occurred in the termite population.
Explain how fossils provide information about extinct species.
Penicillin is a drug that kills bacteria. Today, many bacteria are resistant to this drug. How does
natural selection best explain this observation?
Explain the use of camouflage as an adaptation and provide an example of camouflage.
7th Grade Science Sample Assessment Items
S7L5a-c.
Vestigial structures have little or no function for an organism. How do these structures provide
evidence for evolution?
The diagram to the right shows the beaks of four birds that
developed over time from one parent species. Explain why the
beak shape of each species of bird developed differently.
What conclusion can be drawn from the
diagram to the right about
Dromaeosauridae, Troodontidae, and
Oviraptorosauria?
The diagram shows changes for an insect
population over generations. Explain how
this change could have occurred and its
relationship to gene d.