Science is an organized way to use evidence and study the natural world. Biology is the study of life, and living things share certain characteristics - they are made of cells, can reproduce, have genetic material, grow and develop, obtain and use energy, respond to stimuli, regulate homeostasis, and evolve over time. The scientific method is used to study the natural world through questioning, researching, hypothesizing, experimenting, analyzing results, and drawing conclusions.

1. What is Science?
An organized way of using evidence to learn
about the natural world

2. BIOLOGY
• Study of life
–Bios = Life
–ology = Study of

3. What characteristics
do living things
possess?

4. a. Made of Cells

5. a. Made of Cells (con’t)
I. Unicellular-
composed of
one cell
I. Multicellular
-composed of
more than one
cell.

6. b. Reproduce-sexual or asexual
I. Sexual – when cells from
two different parents unite

7. b. Reproduce-sexual or asexual
II. Asexual – when a single parent
produces offspring IDENTICAL to
itself

8. c. Based on a universal
genetic code
I. All organisms
store information
needed to live,
grow and
reproduce in a
genetic code
called DNA

9. d. Grow and Develop
I. Organisms grow through cell
division
II. Organisms develop through
cell differentiation
 Cells begin to look differently
and perform different jobs
Examples: muscle cells,
nerve cells, skin cells, red
blood cells

10. e. Obtain and Use Energy
(metabolism)
I. Organisms OBTAIN energy directly
from the sun (autotroph), indirectly from
another organism (heterotroph)

11. e. Obtain and Use Energy (con’t)
II. Organisms USE energy in order to
move, grow, repair, and reproduce
 Metabolism – combination of
reactions through which an organism
breaks down materials

12. f. Respond to stimuli
I. Stimulus: Something in the Environment
Stimulus
that makes an organism react, such as
changes in light, sound, temperature, odor

13. g. Homeostasis
I. The process of keeping conditions inside
stable even though environmental
conditions are constantly changing.
II. In Greek : Homeo – same Stasis – state
• Examples
– sweating
– rabbit ears and cooling
– pupil reacting to light
– Lizard sunning itself on a rock
– Clams retaining water during low tide

14. h. Evolve (as a group)
I. Populations of living things CHANGE as a
group over time.
• Examples
– thumb in humans
– camouflage
– spines in cactus

15. T
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16. 4. Scientific Method
1. Ask A Question– Determine the
question or problem that is trying to
be answered
2. Gather Information - Gather as much
information about the topic as
possible
3. Form a Hypothesis – A proposed
answer to the question, written in an
if/then format

17. Scientific Method (con’t)
4. Test the Hypothesis – design and
carry out an experiment
A. Independent (manipulated) Variable
B. Dependent (responding) Variable
C. Controlled Variables
5. Record and Analyze Results –
Summarize what the data means
6. Draw a Conclusion – Restate the
question and how you came to the
result that you did

18. Scientific Method Example
1. Ask a Question: “What light color
will produce the tallest tomato plant?”
2. Gather Information: Research the
purpose of light in helping a plant
grow, how long it takes for a tomato
plant to reach maturity, amount of
water, fertilizers needed, etc.

19. Scientific Method Example (con’t)
3. Form a Hypothesis - IF tomato plants
are grown under a green light, THEN
they will grow faster than plants
grown under red, blue or white lights
4. Test the Hypothesis – design and
carry out an experiment – list the
materials and procedure
Materials: 20 Tomato plants, soil, water,
metric ruler, plant pots, red/green/
blue/white lights

20. Scientific Method Example (con’t)
4. Test the hypothesis (con’t)
1. Gather materials
2. Plant each tomato plant in a pot
containing the same amount of soil
3. Measure plants on day 1 as the initial
height and record.
4. Place four plants under green light, four
under red light , four under blue light, and
four under white light.
5. Water plants daily with 50 mL of water
6. Measure plants every third day and
record.
7. Compare growth.

21. Scientific Method Example (con’t)
5. Record and Analyze Results – record
observations. Make tables/graphs
showing growth of plants over the
period of time tested. Summarize
what the data means using words
control, independent variable,
dependent variable.
6. Draw a Conclusion – Restate the
question, accept or reject your
hypothesis and how you came to the
result that you did.

22. Identify the independent, dependent and
controlled variables in the following
hypothesis
If you add more folds to
a paper airplane, then it
will fly faster.

23. 5. Theory
I. In science, when a
hypothesis has been
proven over and over
again it eventually
becomes a theory.

24. II. Theory: A well
tested explanation that
unifies a broad range of
observations.
III. NOT absolute truth

25. IV. Theories in Biology
• Cell Theory
• Germ Theory
• Big Bang Theory
• The Theory of Evolution by
Natural Selection

26. It’s just a theory
Note: Please keep in mind that the
term “theory” is used very differently
in science than it is used in
everyday language.
Ex: I have a theory as to who will win
the Steelers game
Dictionary Definition: guess,
assumption or speculation