CHAPTER 1 – THE SCIENCE OF BIOLOGY
I. What Is Science?
(A) Organized way of using evidence to learn about
the natural world.
(B) Collection of knowledge that scientists have built
up after years of using this process.
II. Scientific Method – Method used in solving a
problem.
NOTE: Used by more than scientists in solving problems.
(coaches, mechanics, detectives etc).
III. Steps in the Scientific Method:
(A) Step 1 – Observations – gathering data
(information)
This can be Quantitative – expressed in #’s.
Or Qualitative – expressed other than #’s.
1. Inference – logical interpretation based on prior
knowledge or experience.
(B) Step 2 – Hypothesis (Prediction; Educated guess).
1. Proposed explanation for a set of observations.
2. Based on prior knowledge or informed creative
imagination.
3. Represents a possible solution to a problem.
4. Sometimes If…Then statements.
5. Some solved by gathering more data; some
tested by doing controlled experiments.
(C) Step 3 – Test Hypothesis – with a controlled
experiment.
1. Important parts of an experiment
a. Test one variable at a time …if possible.
(Variable – is something that causes the changes
observed in an experiment)
b. Controlled variable –the one(s) that you don’t
change
c. Experimental variable, independent variable) –
contains the variable you are testing. (called the
manipulated variable).
d. Dependent variable-the condition that is
affected by the independent variable
D. Step 4 - Recording & Organizing Data:
1. Tables; Graphs; Averages etc.
2. More data the better.
E. Step 5 – Drawing Conclusions:
1. Based on data and observations.
Example of Famous Experiments: Redi’s Experiment
on Spontaneous Generation Pg. 9
Observations: Flies land on meat that is left uncovered. Later, maggots appear on the meat.
Hypothesis: Flies produce maggots.
Procedure
Uncovered jars
Covered jars
Controlled Variables:
jars, type of meat,
location, temperature,
time.
Several
days pass
Manipulated Variable:
lid
Responding Variable:
Whether maggots appear
Maggots appear
Conclusion: Maggots form only when flies come in contact with meat.
Spontaneous Generation of maggots did not occur.
No maggots appear
Other Examples of Famous Experiments – Spallanzani’s
Experiment pg. 11
This experiment
showed that
microorganisms will
not grow in boiled and
sealed gravy that is
left open to the air.
Questions:
1. What variable was
controlled in this
experiment?
Flask is open
Gravy is boiled
Gravy is
teeming with
organisms
2. What variable is the
experimental (manipulated)
variable?
Flask is sealed
Gravy is free of
organisms.
Louis Pasteur’s Experiment on Spontaneous Generation
Fig. 1-11 pg. 12
Broth is boiled
Broth is free of
organisms for a year.
Curved neck
is removed
Broth is
teeming with
microorganisms.
Questions: 1. Why did microorganisms not grow in the flask
before the neck was removed?
2. Why did the microorganisms grow after the neck was
removed?
F. Step 6 – Theories: well tested explanations that
unifies a broad range of observations.
1. Example: Theory of Evolution.
1-3 Studying Life
(A) Biology – Study of living organisms; study of the living
world.
(B) Biosphere – The part of the Earth that contains all
ecosystems
(C) Levels of environmental organization found on page 21
C. Characteristics of Living Things.
1. Made of units called cells.
a. Unicellular – one-celled.
b. Multicellular – many celled.
2. Reproduction.
3. Based on a universal genetic code. (DNA)
4. Growth & development.
5. Obtain & use materials and energy.
6. Respond to their environment. (Respond to a stimuli)
7. Maintain a stable internal environment.
8. Taken as a group, living things change over time.
(Evolution)
1-4 Tools and Procedures
A. Metric System – Also called the International
System Of Units (SI).
1. Based on units of 10, or moving a decimal place
one place.
2. Base Units: suffixes (end of words)
a. Length/width (linear) = Meter (M)
b. Volume = Liters (L)
c. Weight = Grams (G)
d. Temperature = Celsius (Centigrade)
Boiling = 100 degrees
Freezing = 0 degrees
How to Convert in the Metric System
Prefixes Kilo – (K) = 1000 M, L. G
Hecto – (H) 100 M, L, G
Deka – (dk) 10 M, L, G
deci – (d) 1/10th of a M, L ,G
centi – (c) 1/100th of a M. L, G
Milli – (m) 1/1000th of a M, L, G
Table on Metric Conversions (found on the test)
Sample Problems:
0.05 mm = __________ cm
0.005 cm
585 Kl = ___________ dl 5,850,000 dl
6, 555 dg = __________ mg 655,500 mg
530 Km = ___________ dm 5,300,000 dm
65 mg = ____________ cg 6.5 cg
5.2 Kg = ____________ cg 520,000 cg
150 g = ____________mg 150,000 mg
6.18 L = ___________cl 618 cl
961 cg = ____________Kg. 0.00961 Kg
0.045 L = __________ ml. 45 ml
How to Read Tables & Graphs
NOTE: The graph has a title, & labeled X & Y axis.
1. At what time of day is the rate of water released by leaves equal
to the rate of water absorbed by roots? Answer: Approx. 5:00 PM
2. What pattern does this graph show about water given off and
taken in by a tree?
Answer: Water released by leaves peaks at
2 PM; the water absorbed by roots at 6 PM.
Microscopes
• Simple Microscopes – magnifying glass (use 1
lens)
• Compound Microscopes – use more than
1lens (ex. Light microscope that we use in
class)
• Electron Microscopes (SEM and TEM)
Comparison of SEM and TEM
See your graphic organizer for review
Pg 26
SEM
TEM