Chapter 1: The Science of Life
H-Biology
Biology and You
What is Biology?
Describe 4 specific examples of how you use biology (or how biology impacts you) in your everyday life.
Characteristics of Life
List the seven characteristics of life and give an example of each characteristic. (Use examples that are not in
the textbook)
Define organization and explain how unicellular organisms are organized differently than multicellar
organisms.
What are biological molecules? How do they relate to cells?
Define:
HomeostasisMetabolism-1-
Describe the difference between growth and development.
Explain why reproduction, unlike other characteristics of life, is not essential for the survival of an individual
organism. What is it essential for?
Complete the following questions on page 9:
8.
9.
10.
Diversity and Unity of Life
Read page 10 and the first paragraph on page 11. What does the phrase, “unity within diversity” mean to you?
Draw figure 1-5 from page 10 (you do not have to draw the organisms). List the three domains and the six
kingdoms. Why is this system useful in classifying organisms?
Interdependence of Organisms
What is ecology? How are humans impacting the ecosystem in negative ways?
Evolution of Life
-2-
What is evolution? Do humans evolve over a lifetime? Be specific…why or why not? (Be careful with this
one)!
Explain how natural selection and adaptations are related. How do both of these terms fit together with
evolution?
Science as a Process
List and describe the six common steps of the scientific method. Define any terms where necessary:
1-
2-
3-
4-
5-
6Designing an experiment
Read about a controlled experiment on page 15 & 16. Explain the essential components of such an experiment
and give an example of each.
What is a theory? Where does it fit in the big picture of the scientific method?
Complete the following questions on page 19:
-3-
4-
5-
Microscopes as Tools
Complete the following chart:
Type of Microscope
Maximum
Magnification
What is “used” to see
the image?
Positives/Negatives
Compound Light
Scanning Electron
(SEM)
Transmission Electron
(TEM)
Read pages 21 & 22 carefully. The terms in this section are extremely important…you will be given a
microscope lab soon and will need to know the parts and functions of the microscope inside and out! We
will go into detail when we get to that lab.
-4-
The Characteristics of Life
Use pages 6-9 in your textbook to complete the following.
Name: _________________________________________________________
1.
ORGANIZATION AND CELLS
a. Organization:
___________________________________________________________________________
______________________________________________________________________________
b. Cell:
___________________________________________________________________________
______________________________________________________________________________
c. EXTEND: Some organisms are unicellular and some are multicellular. Create your own
definition of each term by examining the graphics.
i. Unicellular:
__________________________________________________________________
ii. Multicellular:
__________________________________________________________________
UNICELLULAR
(under a microscope)
MULTICELLULAR (under the microscope)
d. Within cells, there are various structures that have different jobs. These structures are called
___________________________. Cells are organized into larger structures. Starting with the
nerve cell…. Lots of nerve cells form _________________________ which works together to
make up the ___________________________ which, together with the spinal cord and
associated nerves, make up the _______________________________________.
-5-
2.
RESONSE TO STIMULI
a. Stimulus:
___________________________________________________________________________
______________________________________________________________________________
b. EXTEND: A stimulus from the environment causes an organism to respond. How would these
organisms respond to each of the following changes in environment?
i. You step outside into the cold:
______________________________________________
ii. A dog smells food:
______________________________________________________________
iii. Light shines on one side of a plant:
______________________________________________
3.
HOMEOSTASIS
a. Homeostasis:
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
b. Give an example of the owl’s homeostatic temperature mechanism.
______________________________________________________________________________
______________________________________________________________________________
c. EXTEND: Watch the Marathon video. List FOUR conditions that must be regulated during the
race: _____________________________________________________________________
Let’s focus in on the way our body controls the amount of GLUCOSE in the blood.
When we eat food, the hormone insulin is released from the pancreas to allow our cells to take
in the glucose which they will use for energy. Insulin also causes any extra sugar to be stored
in the liver and muscles for later use. If something is wrong with this mechanism, a person
will have too much sugar in their blood which is hyperglycemia. If the condition is severe, it
is called diabetes. When sugar is needed in-between meals, the stored glucose is broken down
and released into the blood so that it can be used. If a body does not carry out this process
correctly, a person can have hypoglycemia, which is a lack of blood sugar.
i. What organ controls sugar balance? ______________________________________
ii. What hormone is used to do this?
______________________________________
iii. What results when there is too much sugar in the blood?
______________
iv. What results when there is too little sugar in the blood?
______________
-6-
METABOLISM
d. Metabolism:
_______________________________________________________________________
e. EXTEND: Read the descriptions below and identify the heterotrophic and autotrophic organism.
i. Heterotrophic organisms obtain energy from the food they eat. The bonds that hold the
food molecules together contain energy. When these bonds are broken as the food is
digested, energy is released and can then be used by the organism to perform the other
characteristics of life.
ii. Autotrophic organisms actually make their own food using either light energy or
chemical energy. This food is then broken down to release energy for them to use.
green
1. ____________________________________
4.
2. _________________________________
GROWTH AND DEVELOPMENT
a. What is the difference between growth and development?
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
b. What is the difference between the growth of a nonliving thing as compared to the growth of a
living thing?
____________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
5.
CHANGE THROUGH TIME
a. Describe evolution:
________________________________________________________________________
b. Why is this process important?
________________________________________________________________________
-7-
6.
REPRODUCTION AND INHERITANCE
a. Reproduction is essential to the survival of the _________________________, NOT the
______________________________________________________.
b. The units of heredity that are passed to us from our parents and determine what we look like are
called _______________________.
c. Genes are made up of a molecule called _____________.
d. EXTEND: There are two basic types of reproduction… asexual and sexual. Read the
descriptions below and then label each graphic according to the type of reproduction.
i. Asexualreproduction does NOT require male and female sex cells. In this type of
reproduction, a single organism makes an exact copy of itself in one of the following
ways.
1. Binary fission: Sometimes organisms just divide themselves in two forming two
identical cells!
2. Budding: This is when the offspring grows right out of the parent!
3. Regeneration: Some organisms can even re-grow pieces of themselves they have
lost.
ii. Sexual reproduction is different because most times a male reproductive cell (sperm) and
a female reproductive cell (egg) are required. These cells can be from the same
individual if the organism is a hermaphrodite (yes, there are many organisms that have
this trait such as sponges and worms) or from different individuals - a male organism and
female organism. NOTE: Organisms reproducing sexually do not always have “sex!” In
many cases sperm and egg are released into the water where they meet. Organisms that
do not have egg and sperm can “sexually” reproduce by exchanging DNA.
A. Starfish:
B. Hydra (like a jellyfish):
C. Bacteria:
D. Sea Urchin:
-8-
Are Viruses Living?
Scientists debate whether or not viruses are living. Use Internet and classroom resources to learn
about both sides of the issue. Then, collaborate as a group to defend your assigned side of the issue
in the space below.




Beyondbooks.com: http://www.beyondbooks.com/lif72/2c.asp
Microbial Life Educational Resources: http://serc.carleton.edu/microbelife/yellowstone/viruslive.html
Nanoscale Science Education: http://www.cs.unc.edu/Research/nano/ed/virus.html
What the Heck is a Virus? http://people.ku.edu/~jbrown/virus.html
LIVING
NON-LIVING
Your argument:
-9-
Homeostasis Video
Biology
1. Define homeostasis.
2. Why does the athlete’s body release adrenaline before the race has even started?
3. Once the race has started, the first changes that we see are increased heart rate and blood pressure. What is the
purpose of this rapid increase in blood flow?
4. How does the body increase its oxygen supply?
5. Why do the runners look flushed only 20 minutes into the race?
6. The runners take in regular drinks of glucose and water. What do these two substances do for the body during the
race?
7. How would the athlete know if the muscles were not receiving enough oxygen and food?
8. Why are the marathon runners wrapped in a thermal blanket at the end of the race?
9. What would happen if the temperature controls failed and body temperature became abnormally high?
10. Is it possible for the higher centers of the brain to override the homeostatic systems of the body? Explain your
answer.
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- 11 -
Name
Date
Vocabulary Section I
Period
Biology H
Directions:
Write each of the 15 terms from section I (located on page 5 in your textbook) in the
boxes below. You should then cut-out each word so you have 15 “cards.” You will have 5-7
minutes with your group to arrange the words on the desk anyway you want. You will, however,
have to explain why you used such an arrangement.
12
Name
Date
13
Period
Name
Date
Name: ______________________________
Section 1-1 Review
The World of Biology
Vocabulary Review Define the following terms.
1. development
2. reproduction
3. organ
4. tissue
Multiple Choice Write the correct letter in the blank.
_____ 1. Biology is the study of
a. animals.
b. plants and animals.
c. all living things.
d. energy transfer.
_____ 2. A short segment of DNA that contains instructions for the development
of a single trait of an organism is known as a
a. DNA loop b. gene.
c. library.
d. membrane.
_____ 3. As the cells in a multicellular organism multiply, they become specialized
for different functions in a process called
a. sexual reproduction.
c. photosynthesis.
b. Descent with modification.
d. cell differentiation.
_____ 4. Homeostasis refers to the
a. organization of cellular structures.
b. stable level of internal conditions in organisms.
c. organized structure of crystals.
d. destruction of tropical rain forests.
_____ 5. Photosynthesis is part of a plant’s
a. metabolism.
c. development
b. homeostasis.
d. response to stimuli
14
Period
Name
Date
Period
Short Answer Answer the questions in the space provided.
1. Explain why the cell is called the basic unit of life:
2. Give a specific example of homeostasis:
3. Why is it important to study biology?
4. Contrast the reproduction of bacteria with that of frogs:
Critical Thinking
The organization of a rock is much simpler than that of living things. By what other criteria can
a rock be distinguished from living things?
15
Name
Date
Period
Name: ________________________
Section 1-2 review
Themes in Biology
Vocabulary Review
Distinguish between the terms in each of the following groups of terms.
1. domain, kingdom:
2. diversity of life, unity of life:
3. adaptations, evolution:
4. ecosystem, ecology
Multiple Choice Write the correct letter in the blank.
_____ 1. A “tree of life” explains
a) how organisms are related to each other.
b) how organisms differ from each other.
c) the lineages of various organisms.
d) all of the above.
_____ 2. Which of the following is NOT an important unifying theme in biology?
a. the diversity and unity of life.
b. the relationship between organisms and society.
c. the interdependence of living organisms.
d. the evolution of life.
_____ 3. An example of a domain is
a. Animalia. b. Protista c. Fungi
d. Eukarya.
_____ 4. A trait that improves an individual’s ability to survive and reproduce is a(n)
a. mutation. b. natural selection. c. adaptation. d. domain.
_____ 5. Which of the following statements is true?
16
Name
Date
Period
a. Destruction of the rain forests has no effect on living things.
b. Destruction of the rain forests increases the rate of evolution of rainforest
organisms.
c. Humans have had no impact on the world’s environment.
d. Humans have had a large impact on the world’s environment.
Short Answer
Answer the following questions in the space provided
1. Give an example of how two organisms are interdependant:
2. Why must an adaptation be inheritable if it is to cause a population to evolve?
3. What is natural selection?
4. If two organisms share the same kingdom, must they also share the same domain?
Explain:
5. A female frog has a genetic trait that prevents it from producing eggs. How likely is it
that this trait will spread through the frog population? Explain:
17
Name
Date
Period
Name: _______________________________
The Power of Belief
Take a minute to explain each of the following things, according to what you think they are.
You may also give your opinion on their validity:
a) Voodoo:
b) Fire walking:
c) Therapeutic Touch:
d) Psychics:
e) Astrology:
f) Channelers:
After watching this video, go back and add anything you would like to the above statements, and
answer the following:
(1) What is “magical thinking”?
(2) What is the “placebo effect”?
(3) How can psychics and tarot card readers make so many predictions about people?
(4) How does this video tie in the scientific method and science in general?
18
Name
Date
Period
Identifying the Steps of the Scientific Method
Elephant Communication
This experiment is NOT a controlled experiment because there weren’t two groups set-up to test
the hypothesis. Instead, the researchers used primarily observations of animals. Regardless, the
steps of the scientific method are clearly present. Identify the steps of the scientific method by
highlighting each and labeling them in the margin.
For many years, observers had noticed that elephant herds appear to move, turn,
or stop suddenly and all together without any apparent audible or visual signal. For
example, if one elephant noticed a lion, all the elephants in the herd seemed to
become alarmed. Some might even charge. Scientists wondered how elephants
communicate.
One biologist, Katharine Payne of Cornell University, made an important
observation about elephant communication at the Metro Washington Park Zoo in
Portland, Oregon. While visiting the zoo, Payne felt the air throbbing around her. It
reminded her of the rumbling of thunder, a sound more felt than heard. Payne had
spent 17 years studying the calls of whales and that some whales make sounds that
are too low-pitched for people to hear. When she felt the vibrations, she also noticed
that the skin on an elephant's forehead seemed to be fluttering. Putting this
observation together with her past experiences, she suspected that the vibrations were
generated by the elephants and that they might be using the sounds to communicate.
She also knew that lower-pitched sounds aren't easily absorbed by objects they strike,
and therefore can travel farther than higher sounds before they become too faint to
hear. Thus, Payne suggested that if elephants produce low-pitched sounds to
communicate with other elephants, then there should be some evidence of elephants'
reacting to the low-pitched sounds made by elephants that are far away.
To perform her experiment, Payne went back to the zoo with a tape recorder and a
microphone. She recorded hours of what seemed to her to be silence among the
elephants. At the same time, Payne was making careful notes about the behavior of
the elephants in their compound. When she first played the tape recordings she had
made of the elephants, Payne heard only background noise. This result was not
unexpected, for she hadn't heard any other sound when she made the recordings.
However, when the tapes were played faster to increase the frequency of the sound
waves, Payne discovered that she had recorded hundred of elephant calls. Then she
made sonograms which are pictures of sound based on sound waves. Payne, wanted
to learn more than she could from her experiment at the zoo. She and several
colleagues traveled to Namibia in southwest Africa, where elephant herds roam. She
set up similar equipment to that in the zoo. The researchers placed their equipment at
distances of more than a mile apart. In that way, they could observe whether widely
separated elephant herds responded to the sounds made by other elephants.
Videotaping was also used to document movement and behavior. Her team found
that female elephants emit certain sounds in order to attract mates. Other sounds are
produced by bull elephants to warn other males away from receptive females. So,
upon putting all the evidence together, it was determined that elephants communicate
using low pitched sounds. Payne and her team then wrote a paper and submitted it to
a biology journal to inform other scientists of their discovery.
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Name
Date
Period
Identifying the Steps of the Scientific Method
Insomnia
This experiment is a controlled experiment because there ARE two groups set-up to test the
hypothesis. The steps of the scientific method are clearly present. Identify the 8 steps of the
scientific method by highlighting each and labeling them in the margin.
Scientists at a major university became concerned by recent reports of severe
insomnia in a number of people with previously normal sleep patterns. They
wondered what was causing this increase in patients with insomnia. These
scientists decided to undertake a scientific investigation to try to determine the
cause of this behavior.
The scientists began to track the personal habits of 127 people who had
recently reported the onset of insomnia, in hopes of finding a clue to the cause of
this sleep disorder. Information regarding previous and current sleep patterns,
exercise routines, stress at home and work, eating habits, and other criteria was
gathered over a six-month period. The only common element in the lives of all of
the subjects was the consumption of foods containing a new fat substitute.
Because the fat substitute contained a chemical not typically found in the human
diet, the scientists thought that this chemical was reacting with other chemicals in
the brain to cause the insomnia. The scientists stated that if the chemical in the
fat substitute caused insomnia in the subjects being investigated, then it should
have a similar effect on other people.
The scientists gathered 80 volunteers who agreed to eat three meals a day
while living at the university research center for 60 days. These volunteers had
no previous history of insomnia. They were aware that the meals would be made
up of some foods containing the fat substitute and had been informed of the
potential risks involved. The scientists divided the volunteers into two groups.
Group A consisted of 40 volunteers who were fed meals with foods containing the
fat substitute. Group B consisted of 40 volunteers who were fed meals that did
not contain the fat substitute. At the end of 60 days, the 40 volunteers in Group A
were suffering from insomnia; the 40 in Group B were sleeping normally.
Moreover, within seven days of discontinuing the diet containing the fat
substitute, the sleeping patterns of the members of Group A returned to normal.
The scientists agreed that the chemical in the fat substitute was causing insomnia in
people who ate foods containing this additive and published their work in a scientific journal.
Identify the following:
Experimental group:
____________________________________________________________________________
20
Name
Date
Period
Independent
Variable:____________________________________________________________________
Dependent Variable:
____________________________________________________________________
Control group:
____________________________________________________________________________
Controls (at least 2):
____________________________________________________________________________
21
Label the Parts and Functions of the Compound Light Microscope
Microscope Part
Function
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
22
23
MICROSCOPE LAB
THE MICROSCOPE
The microscope is an instrument that allows us to see cells and things inside cells. It works by
using a series of glass lenses to magnify an object. The main lens that magnifies the specimen is called the
objective and the lens through which you look is called the eyepiece or ocular. There are 4 different
objectives on our microscopes, but NEVER use the largest (most powerful 100x) lens unless specifically
told to do so by your teacher!
CARE OF THE MICROSCOPE
1. Don't tamper with any parts. If something doesn't seem to be working, notify your teacher.
2. Don't allow liquids to come in contact with anything other than a slide. If you do, you will cause
massive electrical fires, possibly resulting in your own explosion.
3. Always use a cover slip when observing wet mounts. This keeps the sample from drying out, it
flattens out your specimen making it easier to focus, and it prevents the specimen from leaping off the
slide and biting you in the neck.
4. When carrying the microscope, always use two hands. This is for two reasons: a) you don't want the
scope to slip and fall costing you thousands of lira; b) you only have two hands.
5. When focusing, always start with the low power objective. This lets you find the area you want before
going to higher power and it prevents you from damaging any lenses.
TROUBLESHOOTING
1. If the image is unclear, CLEAN THE LENS with LENS TISSUE ONLY (anything else will scratch
the lens).
2. If the image is still unclear, REFOCUS using the FINE ADJUSTMENT.
3. If the image appears "washed out" or too dark, CHANGE THE LIGHT INTENSITY using the
DIAPHRAGM and / or the CONDENSER.
4. If you lose your specimen when going up in power, it's because you're a terrible person whom no one
likes. However, it may also be because YOUR SPECIMEN WAS NOT CENTERED. Go back to a
lower power and get the object "dead center", then go up in power.
24
MATERIALS
Please gather the following materials:
1 microscope slide per person
1 coverslip per person
1 pack of lens tissue per table
1 dropper bottle full of water per table
1 pair of scissors per table
1 microscope per person
METHODS AND QUESTIONS
1.
Make a wet mount of a piece of your hair.
A) Place a drop of water on a clean slide
B) Take a hair and lay it in the water
C) Take a clean cover slip and lower it over the hair, being careful that no air bubbles
form
D) Bring it into focus under low 4x power.
E) Using the proper lab drawing format, draw the hair on low (4x) and then on high
(40x) power. Use as much detail as possible!
F) Remember to include title, magnification and labels.
Move the slide to the left, right, up and down. What can you determine about the movement of a
specimen on the stage as compared to its movement through the ocular?
2.
Make a wet mount of the letter "e"
A) Place a lower case “e” from the newspaper (the smaller the better) right side up on a
slide.
B) Add a drop of water.
C) Take a clean cover slip and lower it over the “e”, being careful that no air bubbles
form
D) Bring it into focus under low 4x power.
E) Using the proper lab drawing format, draw the "e" on low (4x) and then on high
(40x) power. Use as much detail as possible!
F) Remember to include title, magnification and labels.
Describe how its position under the microscope differs from its orientation on the slide. In other
words, you placed the "e" on the slide right side up. What happened to the appearance of the "e"
under the microscope?
25
What happened to the size of your field of focus when you went from low power to high power?
Explain. (HINT: think of using binoculars versus using the "naked eye")
Now observe your specimen as you adjust the amount of light by rotating the
diaphragm through the various light settings. Why do very thin objects need low
amounts of light while thick ones require more light?
3.
Take a prepared slide of three threads
A) Place a drop of water on a clean slide
B) Take three small thin threads of 3 different colors and lay them in the water. Form an
asterisk or "snowflake" pattern - all 3 threads need to overlap.
C) Take a clean cover slip and lower it over the threads, being careful that no air bubbles
form
D) Bring it into focus under low 4x power.
E) Using the proper lab drawing format, draw the threads on medium (10x) power. Use
as much detail as possible!
F) Remember to include title, magnification and labels.
From observing the threads, could you discern the colors of the three threads? If so, what does
this tell you about the microscope?
From observing the threads, could you tell which thread was on top, which was in the middle, and
which was on the bottom? Why or why not?
4.
You have already worked with the microscope’s magnifying power; now let’s try it’s resolving
power. Resolving power is the ability of a microscope to give a clear image of the various
“parts” of an object. To observe this, do the following:
-cut out a piece of a color comic from the newspaper and make a wet-mount slide of it.
26
How does this illustrate resolving power?
Return your microscope to low power before removing your slide. Clean and dry your
slide and coverslip, and return all materials to the lab tray when finished.
CONCLUSION
Type and include:
 Describe the function of the scope
 Explain why scopes are important and useful in biology
 Explain how our knowledge of the world would be different if scopes had not been invented.
Give at least 2 specific examples.
 Describe the steps involved in the use of a scope to make and to view a specimen
 Describe at least three things you could do if a specimen appeared dark and / or blurry, and
WHY you would take each of those steps.
27
Name: ______________________________________
Measuring Under the Microscope
We are going to use a unit of measurement called the micron.
One millimeter is equal to 1,000 microns. The first thing we need to do is to calibrate
the microscope at each power. Using the rulers provided, determine the approximate
diameter of the field of view under focusing power in millimeters.
Focusing power (4x) field = ___________ mm
Using this information, let’s calculate the field of view for each power:
(A) Focus power (4x) field = ___________ microns
(B) Low power (10x) = ___________ microns
(C) High Power (40x)
= ____________ microns
Follow instructions on HOW to do a measurement, and then complete the following:
Part 1: Hair
Cut a small piece of hair and make a wet mount slide of it. Using proper sketch
technique, make three sketches of the hair (low, medium, high), carefully measuring
the width of the hair each time. Answer the following questions:
1) Did the width of the hair change from one power to the next?
2) Explain this:
3) Why do only parts of the hair come into focus at any one time?
Part 2: Yeast
Prepare a slide with a drop of yeast solution. Draw and count the yeast (the best you
can) at medium and high power.
1) What happens to the yeast cells from medium to high power? Why?
28
Scientific Method & Blood
INTRODUCTION:
In this lab you will learn to form a hypothesis, conduct experiments
around that hypothesis, and collect and analyze data. One of the most
important characteristics of modern science is its quantitative approach
to solving problems. One of the first scientists to use quantitative
methods was William Harvey, who discovered that blood circulated
through the body. At the time Harvey began his work, anatomists
believed that the liver produced blood from the food that the body
consumed. The blood was then carried by veins to the heart, purified
in the lungs, and then pumped to the various organs of the body,
where it was consumed. Harvey measured that the left ventricle of the
heart held roughly 100 ml of blood. He also measured that the heart
beats an average of 64 times per minute.
QUESTION 1:
From the information above, and assuming that 1 ml of blood weighs 1
g, how much blood would the body need to produce per hour in ( g/hr.)
to replace the blood consumed by the organs? _______g/hr.
Harvey hypothesized that the same blood must circulate
continuously throughout the body.
MATERIALS:
Watch with second hand, or clock
PROCEDURE:
1. While sitting quietly at your desk, find the pulse in your wrist
and count the beats for one minute. You and your lab partner
can do this on yourselves, or each other. Record the names of
both subjects and their beats per minute heart rate on DATA
TABLE 1 as sample 1.
29
Repeat step 1 two more times for each subject. Record the data
in the appropriate place on DATA TABLE 1.
2. Calculate the average pulse rate for each subject and record the
results on DATA TABLE 1.
How do you think standing or holding your breath will affect your pulse rate?
______________________________________________________
QUESTION 2:
Choose one of these activities and formulate a hypothesis about its
effect on pulse rate. What is the independent variable? What is the
dependent variable?
Hypothesis _______________________________________________
Independent Variable _______________________________________
Dependent Variable ________________________________________
4. Repeat steps 1, 2, and 3 for each subject, this time with the
subjects standing or holding their breath. Record your data and
calculations in the appropriate DATA TABLE
DATA TABLE 1: Resting heart rate
NUMBER OF BEATS PER MINUTE
SUBJECT
sample 1
sample 2
AVERAGE NUMBER OF
sample 3
30
BEATS PER MINUTE
DATA TABLE 2: Heart rate standing
NUMBER OF BEATS PER
MINUTE
SUBJECT sample 1
sample 2
AVERAGE NUMBER OF
BEATS PER MINUTE
sample 3
DATA TABLE 3: Heart rate holding breath
NUMBER OF BEATS PER MINUTE
SUBJECT sample 1
sample 2
AVERAGE NUMBER OF
BEATS PER MINUTE
sample 3
Conclusion: Compare your data from step 4 with your data from step 3.
1. How do your results in step 4 compare with the hypothesis you made?
2. What measurement did you use as a control in this investigation?
3. What are some possible sources of error in this experiment?
31
32
IV / DV/ Control Worksheet
______________________
Name
Independent and Dependent Variables, and Controls
Independent Variable: measurement or condition in the experiment that you – the
scientist – change
Dependent Variable: measurement or condition in the experiment that changes because
of a change to the independent variable.
Controls:
Other factors in the experiment that must be kept the same so that
the independent variable is the only variable that is changing or
causing anything to happen.
Remember: in a controlled experiment there can be only ONE independent variable.
Key words to help identify the IV and DV
Independent Variable
If I do this…
The Cause
What you are testing
Dependent Variable
…then this will happen
The effect
The result of those tests
Read the experiments below. Identify the IV and DV. List 2 factors in the experiment that
would be controls, and describe how you would measure the IV and DV (one way for
each). See #1 as an example.
1. Food coloring is added to cold water and hot water. Compare the rate of diffusion (how
fast it spreads out) between cold water and hot water.
IV – the temperature of the water.
DV – The rate of diffusion of the food coloring
Controls – Amount of water – size of beaker – height that food coloring was dropped –
amount of food coloring added
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How would you measure the IV and DV?
Measure IV – use thermometer to gauge temperature of water
Measure DV – often there are numerous ways to measure the DV. For this experiment,
you could:
A) record how far the food dye spreads in a certain period of time
B) record how long it takes for the dye to be completely dispersed throughout the
beaker
C) ?? any others ??
2. How will the growth of tomato plants be affected by water?
IV ________________________________________ DV
_______________________________________
CONTROL 1.____________________________________ 2.
________________________________
Measure IV
___________________________________________________________________
Measure
DV___________________________________________________________________
3. How does sunlight affect the germination (sprouting) of seeds?
IV ________________________________________ DV
_______________________________________
CONTROL 1.____________________________________ 2.
________________________________
Measure IV
___________________________________________________________________
Measure
DV___________________________________________________________________
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