SAMPLE MCA SCIENCE QUESTION
Name______________________________
The U.S. is a culture that eats a lot of meat for their daily diet. Animals are typically grown on
factory farms in large quantities. Because of so many animals in one area, humans typically
feed the animals lots of medicine and antibiotics. This is done to help keep the animals from
getting sick and spreading the sickness easily to each other. You are interested in whether
this constant dose of medicine is affecting humans as well.
You decide to study pigs. Pigs are often given an antibiotic called tetracycline to prevent
illness. Humans frequently are prescribed this antibiotic as well. You decide to get a set of
pigs to do an experiment on. For the first 4 years of the pig’s life, you will feed the pigs
antibiotics. You then measure the percentage of bacteria that are resistant to the antibiotic in
them (Experiment A). For the second 4 years of the pig’s life, you take the pigs off the
tetracycline. You measure again the percentage of bacteria that are resistant to the antibiotic
(Experiment B).
Here are your results:
EXPERIMENT A:
EXPERIMENT B:
The Effect of Eliminating Antibiotics
from Pigs' Diets on Bacterial Resistance
During Years 5-8 of a Pig's Life
60
60
50
50
Percentage of Bacteria Showing
Resistance (%)
Percentage of Bacteria Showing
Resistance (%)
The Effect of Using Antibiotics on
Bacterial Resistance in Pigs During the
First 4 Years of Their Life
40
30
20
10
0
Year 1
40
30
20
10
0
Year 2
Year 3
Year of Study
Year 4
Year 5
Year 6
Year 7
Year 8
Year of Study
MULTIPLE CHOICE:
____ 1) Which statement best describes the occurrence of resistance in bacteria in
Experiment A?
A) As antibiotics were used, resistance went down over time.
B) As antibiotics were used, resistance went up over time.
C) As antibiotics were used, resistance levels stayed the same.
D) As antibiotics were used, resistance levels went up at first and then
went down dramatically.
____ 2) Which statement best describes occurrence of resistance in bacteria
Experiment B?
A) As antibiotics were eliminated, resistance went down over time.
B) As antibiotics were eliminated, resistance went up over time.
C) As antibiotics were eliminated, resistance levels stayed the same.
D) As antibiotics were eliminated, resistance levels went up at first and
then went down dramatically.
____ 3) Between Experiment A and Experiment B, what is the independent variable?
A) The use of antibiotics in pigs
B) The type of antibiotics used
C) The percentage of bacterial resistance to antibiotics
D) The number of years pigs were raised
____ 4) In Experiments A and B, what is the dependent variable?
A) The use of antibiotics in pigs
B) The type of antibiotics used
C) The percentage of bacterial resistance to antibiotics
D) The number of years pigs were raised
____ 5) What is this experiment an excellent example of?
A) Artificial selection
B) Evolutionary selection
C) Natural selection
D) Sexual selection
____ 6) Which statement best describes the reason why antibiotic use can promote a
larger population of resistant bacteria?
A) The antibiotic contains resistant bacteria inside it. The continued use
of the antibiotic allows more of these resistant bacteria to get into
pigs.
B) Bacteria inside of pigs tries to fight off antibiotics by purposefully
reproducing more resistant bacteria for future generations.
C) Bacteria can detect antibiotics in their environment. When they do,
they mutate their DNA to allow for increased resistance to survive
their environmental conditions.
D) The antibiotics initially kill most bacteria. The few survivors have a
resistance. These bacteria reproduce and spread the resistance trait
into future generations.
____ 7) Predict what you think would happen if you never stopped the use of antibiotics in
pigs after year 4 of the study and continued to use them:
A) The percentage of bacteria that are resistant to antibiotics would
continue to increase from year to year.
B) The percentage of bacteria that are resistant to antibiotics would
decrease from year to year.
C) The percentage of bacteria that are resistant to antibiotics would stay
at the same level as seen in year 4.
D) Pigs would become immune to all antibiotics used in modern
medicine today.
____ 8) Evolution is the process of change in an organism over time. There are many
theories for evolution. Charles Darwin proposed one of the most widely accepted theories for
evolutionary change. What was his theory called?
A) Theory of Evolutionary Progress
B) Theory of Intelligent Design
C) Theory of Natural Selection
D) Theory of Uneven Reproductive Capacities
____ 9) Predict what happens if humans continue to consume pig products that have been
continually raised on antibiotics:
A) Humans show no significant effects, as human systems are designed
to kill off bacteria found in pigs.
B) Humans get poisoned, since they are more exposed to the poisons
found in antibiotics needed to kill off bacteria.
C) Humans are at a higher risk of infection from antibiotic-resistant
bacteria.
D) Humans become healthier overall, since they are indirectly
consuming antibiotics, which kill bacteria that make them sick.
____ 10) In a population of non-resistant bacteria, a single bacterium is born with the
genetic ability to resist antibiotic treatment. All bacteria are of the same species. What is the
ultimate cause of this change in the single resistant bacterium?
A) The resistant bacterium has a more efficient mRNA and tRNA system
than the non-resistant bacteria.
B) The resistant bacterium has a change in its DNA sequence which
creates the ability for resistance.
C) The resistant bacterium was exposed to more sunlight, which
ultimately is the source of all energy and mutating forces in nature.
D) The resistant bacterium has a lot more DNA in total and is able to
survive easier with more DNA.
SHORT ANSWER (make sure you answer THOROUGHLY…one word answers or phrases
will not make the cut for questions that require description!!!!):
11) State one qualitative observation you could make from either experiment. [HINT –
qualitative observation involves an observation that does not involve or use a number].
State one quantitative observation you could make from either experiment [HINT –
quantitative observation involves an observation that does involve or use a number]
12) This type of resistance in antibiotics is due to human influence over the evolutionary
process. Name and describe another example of this type of influence in the world.
13) You know that organic farming does not use any antibiotics. You are interested in
knowing if organic meat from pigs in the supermarket has less resistant bacteria on it than
non-organic pig meat at the supermarket. Propose how you would design or set up a simple
experiment to test this question. Make sure you include:
-- the purpose of the experiment
-- short procedure
-- what variables you will change in your experiment
-- what you will attempt to keep constant in your experiment
14) State an appropriate hypothesis for the experiment you explained from the previous
question.
15) There are three different colors of beetles in your yard. The colors are green, brown,
and blue. You raise 1000 of each type and release all of them into your backyard. Your yard
is covered in grass, which the beetles live in. A month later, you go out and collect a sample
of the beetles that live in the yard.
Predict what results you expect to see in terms of the beetle sample you collect:
Explain your reasoning for why you say this:
If the yard stays healthy for many years, predict what will happen to the color frequencies in the beetle
population over future year. Explain your reasoning for this prediction, making sure your answer is grounded
in a theory of evolution.