Download Life Science - Parma City School District

OAT Practice
th
8 Grade Science
Life Sciences
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1) Which interaction between
organisms would be
described as parasitic?
A. A mosquito feeding on the
blood of a dog
B. A bee gathering nectar and
pollen from a flower
C. A cleaner shrimp picking
dead skin off a large fish
D. A nonpoisonous snake
mimicking a poisonous
snake
1. Which interaction between organisms would be described as
parasitic?
A. A mosquito feeding on the blood of a dog
This is the correct answer.
The mosquito feeding on the blood of a dog is a parasitic
interaction. A parasitic interaction is a relationship in which one
organism is helped by the interaction while the other organism is
hurt by it. The mosquito is helped by the blood it gets, and the dog
is hurt by the mosquito that is biting it.
B. A bee gathering nectar and pollen from a flower
If a student chooses B, he or she may have thought that a
mutualistic interaction (a relationship between two different
organisms that helps both organisms) was the same as a parasitic
interaction. A bee gathering nectar from a flower helps both the bee
and the flower, so it is a mutualistic interaction, not a parasitic
interaction.
C. A cleaner shrimp picking dead skin off a large fish
If a student chooses C, he or she may have thought that a parasitic
interaction was the same as a mutualistic interaction. The cleaner
shrimp and the large fish are both helped by the cleaner shrimp
picking dead skin off the large fish. The cleaner shrimp gets food
and the large fish is helped by having dead skin picked off its body.
The relationship between the shrimp and the fish is a mutualistic
interaction, not a parasitic interaction.
D. A nonpoisonous snake mimicking a poisonous snake
If a student chooses D, he or she may have thought that mimicry
was the same as parasitism. Mimicry takes place when a harmless
organism acts or looks like a poisonous organism. Mimicry tricks
predators into thinking the nonpoisonous organism is poisonous
and makes it less likely that the predator will eat the nonpoisonous
organism. In this interaction, the nonpoisonous snake benefits and
the poisonous snake is not hurt. This is not an example of a
parasitic interaction.
A park is home to a large number of
robins, squirrels and rabbits. The
robins and squirrels live in the park’s
trees. The robins feed on earthworms
and insects that live on the ground.
The squirrels eat the acorns produced
by the park’s oak trees. The rabbits
hide in the bushes and feed on the
grass.
2) Which factor would directly limit
the number of rabbits that could
live in this park?
A. Number of robins
B. Number of Bushes
C. Number of Acorns
D. Number of Squirrels
2. Which factor would directly limit the number of
rabbits that could live in this park?
A. Number of robins
If a student chooses A, he or she may not understand
that robins and rabbits live in different places and eat
different things, so they do not compete or struggle for
the same shelter or resources (like food).
B. Number of bushes
This is the correct answer.
The number of bushes will limit the number of rabbits
that can live in the park ecosystem (environment).
Bushes are an important part of rabbit habitat. They
provide shelter for rabbits. If the number of bushes is
limited, fewer rabbits will be able to live in the
ecosystem.
C. Number of acorns
If a student chooses C, he or she may not understand
that rabbits do not eat acorns. The number of acorns
will not limit the number of rabbits that can live in the
park.
D. Number of squirrels
If a student chooses D, he or she may not understand
that rabbits and squirrels do not use the same
resources (like food), so they do not compete for
resources.
3) In which environment is
white fur color an
advantage for survival?
A. Desert
B. Grassland
C. Artic Tundra
D. Temperate forest
3. In which environment is white fur color an
advantage for survival?
A. Desert
If a student chooses A, he or she may not
understand that an animal with white fur would
stand out against the sand and rock of a desert.
B. Grassland
If a student chooses B, he or she may not
understand that an animal with white fur would
stand out against the green plants in a grassland.
C. Arctic tundra
This is the correct answer.
An animal with white fur would be more
difficult to see against the snow and ice in an
arctic tundra. The white fur would make it
harder for predators to find a white animal in a
white place. So, having white fur is an
advantage in an arctic tundra.
D. Temperate forest
If a student chooses D, he or she may not
understand that an animal with white fur would
stand out against the plants and substrate, or
surface, of a temperate forest.
4) Which cell structure
carries out a function
for a cell that is similar
to the function that
bark carries out for a
tree?
A. Cell wall
B. Nucleus
C. Chloroplast
D. Mitochondrion
4) Which cell structure carries out a function for a cell
that is similar to the function that bark carries out for
a tree?
A. Cell wall
This is the correct answer.
The cell wall is the part of the cell that works like the
bark of a tree. The cell wall makes the cell rigid, or
stiff, and it keeps dangerous substances from getting
into the cell.
B. Nucleus
If a student chooses B, he or she may not understand
that the nucleus is a cell structure (part of a cell) that
holds the genetic material that directs the making of
proteins that cells need to do their work. The nucleus
is also where DNA is replicated or copied.
C. Chloroplast
If a student chooses C, he or she may not understand
that one of the jobs of bark is to protect the tree. The
chloroplast of a cell does not protect the cell, but it is
responsible for photosynthesis (the way that green
plants use sunlight to make food).
D. Mitochondrion
If a student chooses D, he or she may not understand
that a mitochondrion breaks down nutrients, like
sugars, into a form of energy that is used.
The diagram at the right
represents a cross section of a
lagoon and some of its
aquatic organisms. A
magnified view (400X
magnification) of each
organism is shown.
Paramecia usually reproduce
asexually. Fish reproduce
sexually. Suppose the
environmental conditions in
the lagoon change.
5) What advantage will the fish population
have over the paramecium population?
A. Sexual reproduction produces offspring that
are identical to the parents.
B. Sexual reproduction decreases the genetic
variability in the fish populations.
C. Sexual reproduction limits the spread of
harmful characteristics in fish populations.
D. Sexual reproduction allows populations to
adapt to new conditions over fewer
generations.
5.
A.
B.
C.
D.
What advantage will the fish population have over the paramecium
population?
Sexual reproduction produces offspring that are identical to the
parents.
If a student chooses A, he or she may have thought that asexual
reproduction (reproduction that happens without the fusion of two
gametes or sex cells) produces or makes offspring that are not identical
to, or the same as, the parents. But this is the opposite of what is true.
Offspring that are identical to the parents would not be better for the
fish population if the environment in the lagoon changes.
Sexual reproduction decreases the genetic variability in the fish
populations.
If a student chooses B, he or she may have thought that sexual
reproduction (reproduction that happens with the joining of two
gametes or sex cells) lowers genetic variation (or variety/differences in
genes). But sexual reproduction will cause higher genetic variation
instead of lower genetic variation. Lower genetic variation would not
be better for the fish population if the environment in the lagoon
changes.
Sexual reproduction limits the spread of harmful characteristics in fish
populations.
If a student chooses C, he or she may have thought that asexual
reproduction makes having harmful or dangerous traits more common.
But an organism that reproduces sexually can carry but not show the
harmful trait, so when it reproduces, the harmful trait can continue to
be passed on to offspring even if you can’t see it.
Sexual reproduction allows populations to adapt to new conditions
over fewer generations.
This is the correct answer.
Sexual reproduction makes variety/changes in a population more
common. There will be more and more variation through sexual
reproduction, because new combinations of good changes can show up
in organisms by exchanging genes with a partner and recombining
those genes.
The diagram at the right
represents a cross section
of a lagoon and some of
its aquatic organisms. A
magnified view (400X
magnification) of each
organism is shown.
Structure Z serves the
same function in each of
the organisms.
6) What is the
function of structure Z in the
water lily, fish and paramecium
cells?
A. To move the cells
B. To control cellular activities
C. To carry out photosynthesis
D. To allow nutrients to enter and
exit the cells
6. What is the function of structure Z in the water lily, fish
and paramecium cells?
A. To move the cells
If a student chooses A, he or she may have thought that
structure Z, the nucleus, helps in locomotion, or moving
around. The nucleus may control activities inside the cell
that change the way the cell moves, but the job of the
nucleus is not to move cells. Also, the water lily and fish
cells do not move on their own.
B. To control cellular activities
This is the correct answer.
Structure Z points to the cell’s nucleus. The nucleus
controls what a cell does and how it works.
C. To carry out photosynthesis
If a student chooses C, he or she may have thought that
structure Z, the nucleus, caught light energy in
photosynthesis (the process that green plants use to make
food from sunlight). Chloroplasts are responsible for
photosynthesis in the plant cell, and a fish and
paramecium cell would not have any chloroplasts.
D. To allow nutrients to enter and exit the cells
If a student chooses D, he or she may have thought that
structure Z, the nucleus, lets nutrients go inside and
leave the cell. But it is the cell membrane and cell wall
of the plant, and cell membrane in the animal and
paramecium cells, that let nutrients go into and leave the
cell.
Scientists see three
layers of rock exposed
on the side of a hill.
The bottom layer is
sandstone with fossils
of a certain species of
reptile found only in
this geographic
location. The middle
layer is volcanic ash.
The top layer is mud
stone (shale) with fossils of a different species of reptile.
7) The fossil evidence supports which hypothesis
about the extinction of the older reptile species?
A. The older reptile species went extinct because
sea levels rose and flooded its habitat.
B. The older reptile species went extinct because a
predator was introduced into the environment.
C. The older reptile species went extinct because it
could not compete with the younger reptile
species.
D. The older reptile species went extinct because a
volcanic eruption caused the environment to
change.
7. The fossil evidence supports which hypothesis about the
extinction of the older reptile species?
A. The older reptile species went extinct because sea levels
rose and flooded its habitat.
If a student chooses A, he or she may have thought that
the sea level going up made the older reptile species go
extinct. But there is not enough information in the fossil
record to support this conclusion.
B. The older reptile species went extinct because a predator
was introduced into the environment.
If a student chooses B, he or she may have thought that
the younger reptile species was a predator of the older
reptile species. But the fossil evidence does not show
that the two species lived at the same time.
C. The older reptile species went extinct because it could
not compete with the younger reptile species.
If a student chooses C, he or she may have thought that
the two reptile species ate the same food. But there is not
enough information in the fossil record to determine the
exact diet of the species.
D. The older reptile species went extinct because a
volcanic eruption caused the environment to change.
This is the correct answer.
The older reptile fossil does not show up in the younger
(top) rock layers, which means that this species went
extinct before, or shortly after, the volcano erupted.
Earthworms and
birds have strong
muscular gizzards.
The gizzard grinds
food into small bits
before it passes on to
the intestine. Mammals, in
contrast, do not have gizzards.
8) Why do earthworms
and birds need to have
gizzards but mammals
do not?
A. Earthworms and birds are not equipped
to chew food.
B. Earthworms and birds eat food that is
difficult to digest.
C. Earthworms and birds have intestines that
work inefficiently.
D. Earthworms and birds do not have
stomachs to mix moistened food.
8. Why do earthworms and birds need to have gizzards but
mammals do not?
A. Earthworms and birds are not equipped to chew
food.
This is the correct answer.
Birds and worms do not have teeth to chew food. So, the
crop stores food and the gizzard grinds up food before it
is passed on to the intestine.
B. Earthworms and birds eat food that is difficult to digest.
If a student chooses B, he or she may have thought that
earthworms and birds have a hard time breaking down
food. Even though some birds and earthworms eat food
that is hard to break down, this does not tell why they
have gizzards. The two animals need the gizzards to
break down food because they cannot chew their food.
C. Earthworms and birds have intestines that work
inefficiently.
If a student chooses C, he or she may have thought that
the gizzard makes up for something (the intestines) that
does not work. But the intestines work the same in all
animals. For all animals, food has to be broken down
into small pieces before it goes on to the intestine.
D. Earthworms and birds do not have stomachs to mix
moistened food.
If a student chooses D, he or she may have thought that
birds and earthworms need a crop and gizzard because
they don’t have a stomach. The picture shows that a bird
does have a stomach.
9. Which is an example of
a group of cells with a
common structure and
function?
A. Stomach
B. Muscle tissue
C. Mitochondria
D. Digestive system
9. Which is an example of a group of cells with a
common structure and function?
A. Stomach
If a student chooses A, he or she may have thought
that all of the cells in the stomach do the same
thing, but the stomach is made up of many kinds of
tissues (like muscle and nerve cells) so these cells
do not look the same or do the same thing.
B. Muscle tissue
This is the correct answer.
Students must know that muscle tissues are made
up of cells that look the same and do the same
thing.
C. Mitochondria
If a student chooses C, he or she may have thought
that mitochondria are made of cells with the same
structures and function, but a mitochondrion is an
organelle and has its own structure and function.
D. Digestive system
If a student chooses D, he or she may have thought
that all of the cells in a digestive system do the
same thing, but the digestive system is made up of
many different organs, so the cells do not look the
same or do the same things.