Transcript Scientific Thinking

Chapter 1: Scientific Thinking
Your pathway to understanding the world
Learning Goals
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Describe what science is.
Describe what biology is.
Describe the major themes in biology.
Describe the scientific method.
Describe how the scientific method can be
used to help make wise decisions.
What is a fact?
I prefer “body of evidence”. As new
evidence is revealed, science changes!
Scientists
 Are
curious
 Ask questions about how the world works
 Seek answers
• Does the radiation released by cell phones
cause brain tumors?
• Are anti-bacterial hand soaps better than
regular soap?
• Do large doses of vitamin C reduce the
likelihood of getting a cold?
Biology is the study of life.
What role does biology
play in your life?
Defining Life…
5 Characteristics Unique to
Living Things:
1. Composed of cells
2. Interacts and responds to
other living things
3. Grows and reproduces
4. Actively transforms energy
5. Changes and adapts over
time leading to a wide
diversity of organisms
Influenza Virus
Why should we learn about Biology?
• All educated
citizens should
have a basic
understanding
about where we
came from.
– Evolution
– Reproduction and
Genetics
Why should we learn about Biology?
• All educated citizens
should have a basic
understanding of
themselves.
– Be healthy
• Nutrition
• Avoid disease
– Interactions with other
living things
Why should we learn about Biology?
• All educated
citizens should
have a basic
understanding
about where
we’re heading.
– Human
evolution has
made us the
dominant
animal.
The most important questions in biology:
What is the chemical and physical basis for life
and its maintenance?
 How do organisms use genetic information to
build themselves and to reproduce?
 What are the diverse forms that life on earth
takes and how has that diversity arisen?
 How do organisms interact with each other and
with their environment?
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The Cell is the smallest unit of life.
2 Main Kinds of Cells:
1. Prokaryotic
2. Eukaryotic
These cells differ
structurally, but the
chemical code
(DNA) uses the
same 4 letters of
the alphabet, A, G,
C, and T.
Hierarchical Organization:
Many levels of organization
within the biosphere.
A cell is life’s basic unit of
structure and function in all
organisms – Biology
Each cell consists of an
enormous number of
chemicals cooperating to
embody the properties of life
– Chemistry
Organisms interact with other
living things and their
environment – Ecology
Hierarchical Organization:
Until recently, 5 main
kingdoms was the
classification scheme.
• Bacteria and Archaea
are prokaryotes. New
evidence reveals
important genetic
differences.
• The domain Eukarya,
contains 4 Kingdoms of
eukaryotes.
•Debate continues on
the kingdom level as
new DNA comparisons
are revealed.
The Power of Evolution: Biology’s Unifying Theme
Using fossil records, we trace the historical evolution of
the bear.
From the fossils of primeval bacteria (3 billion years ago),
we recognize connections to our own cells.
All Life is
connected,
and
evolution is
the unifying
theme!
An
evolutionary
tree is only a
hypothesis.
Evolution at
Work!
1. Environmental
Pressure = taking
the antibiotic
2. Genetic variability
= the gene for
resistance
3. Successful
Reproduction =
pass that gene on
to the next
generation.
Abuse and misuse of antibiotics is
speeding the evolution of resistant
bacteria.
“How do you know that is
true?”
The single question that
underlies critical thinking
Critical thinking: To question
with an open mind and search for
truth using reason and logic.
Can we trust the packaging claims
that companies make?
clinical drug trials and evidence
CEO says: people “are really not scientifically
minded enough to be able to understand a clinical
study.”
Argument against labeling Genetically Modified
foods… people won’t understand what it means.
Cloning Endangered Species
You don’t have to be at the mercy of
charlatans, advertising, or slick
packaging.
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Learn exactly what it means to have scientific
proof or evidence.
Learn what it means to think scientifically.
 Learn how to use the knowledge we gain to make
wise decisions
 Biological Literacy:
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 Use
the process of scientific inquiry to understand real
world issues
 Communicate your thoughts
 Integrate into your decision making
End
1.3 The scientific method is
a powerful approach to
understanding the world.
If science proves some belief of
Buddhism wrong, then Buddhism will
have to change
—Dalai Lama, 2005
Science helps us understand when we should
change our mind.
Scientific Thinking Is Empirical…
…based on experience and observations
that are rational, testable, and repeatable.
Which answer below does not exemplify
knowledge gained through empirical testing?
1. Sugar tastes sweet.
2. The sky looks blue during the daytime.
3. I can smell freshly popped popcorn from a
distance.
4. A rabbit’s foot can bring good luck.
 The
scientific method is a particularly
effective approach because it is empirical,
rational, testable, repeatable, and selfcorrecting.
Does taking echinacea reduce the intensity or
duration of the common cold?
The goal is to:
Propose a situation
that will give a
particular outcome
if your hypothesis
is true but that will
give a different
outcome if your
hypothesis is not
true.
Does echinacea help prevent the common cold?
Hypothesis: Echinacea reduces the duration and
severity of the symptoms of the common cold.
Repeatable experiments increase our confidence.
1.10 When do hypotheses
become theories?
Two distinct levels of understanding that
scientists use in describing our knowledge
about natural phenomena
A theory is a hypothesis for natural phenomena
that is exceptionally well-supported by the
data.
A theory is broad in scope and has been tested
repeatedly by independent researchers who
come to the same conclusions, a large general
body of supporting evidence.
Interpreting
graphs and
statistics can help
us draw
meaningful
conclusions.
Does having
access to a
textbook help a
student to
perform better in
a biology class?
Watch out for biases…
1.16 There are limits to what science
can do.
 The
scientific method will never prove or
disprove the existence of God.
 Understand
 What
love?
is beauty?