BIOLOGY: Chapter 1
The Science of Biology
1.1 The Science of Biology
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“Science” is basically two things:
A body of knowledge… an
accumulation of things we have
learned about the universe
– A process… an organized way of
gathering and analyzing evidence
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Goals of science
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The goal of science is to provide
explanations for events in the natural world
Learning about science involves
understanding what we know, but also
means understanding what we DON’T know
Uncertainty is part of the scientific process
and is limited by our technology and methods
The Scientific Method
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An organized process used to answer a
question
Start with a testable hypothesis
Repeatable experiments
Conclusion must be supported by the data…
scientists sometimes overreach their
experiments and “jump to conclusions”
The Scientific Method
1.
Background research to understand the
state of knowledge of the subject before you
begin: What is already known about the
topic? What types of methodology have
been used in similar experiments?
*Thorough background research is what
makes the “educated guess” educated 
The Scientific Method
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Form a testable hypothesis based on your
background research
Design a repeatable experiment using the
appropriate controls and variables (only
manipulate one variable at a time!)
Conduct the experiment and record data
~ multiple trials
~ samples size must be appropriate…bigger is
better!
The Scientific Method
5. Analyze the data: statistical analysis and
graphing (how different is different?!)
6. Form a conclusion: use your data analysis to
determine if your hypothesis was supported
7. Report your results: scientific research
journals, conferences, etc
Example of a scientific hypothesis
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Null hypothesis (Ho): The male and female
students have the same IQ
Alternative hypothesis (Ha): The male and
female students have significantly different
IQ scores
Must use statistical analysis to show
“significance”
Example of a scientific hypothesis
Control (population):
Avg IQ score = 100
Male test group (n=10): Avg IQ score = 101
Female test group (n=10): Avg IQ score = 102
Are these two results truly different? Depends
on the sample size and the range… must
use statistics to determine, but probably not!
Controls and variables
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Control group: exposed to the same conditions as
the experimental group with the exception of the
experimental variable… the control group is the
standard against which the experimental groups are
compared
Independent variable: the condition that is tested (ie
the thing you change in the experiment)
Dependent variable: the condition that results from
changing the independent variable (ie what is
observed or measured)
DRY MIX: How to graph results
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D: dependent variable
R: also called the responding variable
Y: graphed on the Y axis
M: manipulated variable (what you change)
I: also called the independent variable
X: graphed on the X axis
Writing experimental procedures
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Must be clearly written so that anyone can
follow your instructions
Numerical order, like writing a recipe
Use sizes, amounts, units of measure
Full sentences with punctuation!
Include safety procedures, set up and
disposal procedures
Make sure to include number of trials,
sample sizes, etc
Results/discussion
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Results should be given in both
graphs/charts and written form
Extensive discussion attempts to make
sense of what you found
What does the data mean?
What kinds of things made sense or not?
Problems or other questions that arose?
Conclusions
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Was your hypothesis supported?
Do not overreach the limits of your study
The case of the biting dogs…
Recommendations/Future studies
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Addresses possible solutions to problems
you encountered
Things you would like to do differently or
repeat in a different way
“Offshoots”…what other questions did your
research raise? This is how most real
research is generated!
Some researchers work their entire careers
on the basis of one original question 
Publication/peer review process
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“Peer reviewed literature” is often very specific
to certain disciplines (ie scientific journals)
Process involves sending drafts of manuscripts
to experts in the field who review it
anonymously and make recommendations
Edits and revisions are the norm, sometimes
very extensive
Often takes up to a year or more
Helps to keep science “honest” and as correct
as possible
1.2 Science in context
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Attitudes of a good scientist:
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Curiosity
Skepticism
Open-mindedness
Creativity
1.2 Science in context
Theory: a well-tested explanation that unifies a
broad range of observations and hypotheses
and enables scientists to make accurate
predictions about new situations
Theories are based on much EVIDENCE and
supported by DATA
Theories vs. laws
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Theories do not become laws!
Laws (such as ideal gas laws or Newton’s
laws) are concise and specific descriptions of
how some aspect of the natural world is
expected to behave in certain situations.
Theories are more dynamic and complex.
They encompass a greater number of ideas
and hypotheses than laws and are constantly
fine-tuned through the process of science.
Bias
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Scientists must make every effort to avoid
bias (bias is not scientific!)
Bias does creep into science through funding
and political issues, but should be seen and
confronted
The case of the disappearing whales of
Prince William Sound…
Exxon Valdez spill
Prince William Sound AK
1989
1.3 Studying Life
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How do biologists determine if something is
“living” or “nonliving”? (biotic or abiotic)
They must meet certain criteria
Some things (VIRUSES!) meet some but not
all of the criteria…grey areas exist
Characteristics of Living Things
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Based on a universal genetic code (DNA)
Grow and develop
Respond to their environment (stimulus &
response)
Made up of cells
Reproduce (asexually or sexually)
Maintain a stable internal environment
(homeostasis)
Obtain and use energy and materials (metabolism)
*Taken as a group, living things evolve.
Three Domains of Life
6 kingdoms of organisms
Biotic vs. Abiotic