April 18, 2012
Question 2
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
April 18, 2012
A. a mosquito feeding on the
blood of a dog
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.
April 18, 2012
Question 14
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.
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
April 18, 2012
B. number of bushes
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
April 18, 2012
Question 23
In which environment is
white fur color an
advantage for survival?
• A. desert
• B. grassland
• C. arctic tundra
• D. temperate forest
April 18, 2012
C. arctic tundra
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.
April 18, 2012
Question 28
Paramecia usually reproduce asexually.
Fish reproduce sexually. Suppose the
environmental conditions in the lagoon
change.
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.
April 18, 2012
D. Sexual reproduction allows populations
to adapt to new conditions over fewer
generations.
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.
April 18, 2012
April 18, 2012
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.
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.
April 18, 2012
A. Earthworms and birds are not
equipped to chew food.
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.
April 18, 2012
Male mussels release sperm into the water. Female mussels take
the sperm into their gill chambers where fertilization occurs. Young
mussel larvae are released into the water where they float freely
until they attach to the gill of a host fish. After a few weeks, they
reach the juvenile stage and drop off. After the juvenile drops off the
fish gill, it burrows into the river bed and begins the life cycle all over
again.
The parasitic behavior of the larvae benefits the mussel
in two ways. One benefit is that the fish provides
nutrition for the larvae when they are attached to its gill.
What is the second way this behavior enhances the
survival of the mussel species?
• A. The large size of the fish provides the mussel
larvae with plenty of room to grow.
• B. The parasitism increases the opportunity for the
mussels to mate with other mussel species.
• C. The mobility of the fish spreads the mussels to
areas they would otherwise be unable to reach.
• D. The location of the larvae on the gills of fish
reduces the exposure of the larvae to oxygen-rich
water.
April 18, 2012
April 18, 2012
C. The mobility of the fish
spreads the mussels to areas
they would otherwise be unable
to reach.
The larvae of mussels attach to
the gills of fish, so they travel
with the fish and then drop off in
places where the adult mussels
could not go by themselves.
This lets the mussels live and
reproduce in new areas, so
there is less competition
between mussels from the same
species.
April 18, 2012