Transcript N.S. 100 Lecture 1 - PPT Scientific Method Assignment Page

Frank Visco – Biology and Chemistry
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Science - what is it?
A collection of knowledge about the natural world
Astronomy ~ Biology
Chemistry ~ Geology
Physics ~ …… others
Most scientific knowledge is in the
form of Theories
Theory:
General set of principles
supported by evidence
that is used to explain
some aspect of nature. Theories may change over time
Example - Biological Theories of Aging
Wear and tear theory
Autoimmunity theory
Free radical theory
Programmed cell death theory
Somatic mutation theory
Homeostasis theory
15 year old boy with
premature aging gene
Inductive and Deductive Reasoning
~ as used in the Sciences ~
Inductive:
specific examples used to
form a generalization
(experiments that lead to
a conclusion)
“Ok, there’s the
sun, so that
direction is up.”
Deductive:
generality applied to specifics
(information presented in a
book on how the brain
Inductive or Deductive?
works)
Scientific Method establishes Theories:
Steps in the Scientific Method:
1. OBSERVATION of some phenomenon
2. Establish a HYPOTHESIS or generalization to explain
observations (note: this is inductive reasoning)
3. Further observations to TEST hypothesis
4. Establish a THEORY (stronger than a hypothesis) to
explain the observations
5. Make PREDICTIONS based on theory
(note: this is deductive reasoning)
6. Continued TESTING of theory
~ Examples of Theories ~
Theories on Global Warming
Theories on origin of HIV & AIDS
Theories on inheritance
Theories on brain chemistry and behavior
Theories on species extinction
Theories on nutrition and health
Theories on genetics and health
Example of Scientific Method
1.
Scientist notices (observation) that a certain
chemical, “X”, appears to inhibit cancer
2
Scientist makes an “educated” guess that X can inhibit
cancer; this is a hypothesis (inductive reasoning).
3.
Scientist then conducts specific experiments to test the
hypothesis, “X can inhibit cancer.” Further experiments
suggest that X inhibits cancer.
4.
Scientist then theorizes (inductive reasoning) that X
inhibits cancer; other scientists may test theory; Federal
Food and Drug Administration (FDA) tests X to see if it is
true. FDA approves Drug X for treating cancer.
5.
Patient with cancer visits doctor; doctor predicts (deductive
reasoning) that if I treat you with Drug X, that Drug X may
inhibit the growth of your cancer.
X
Drug approval process:
1. $400,000,000 to get a drug to pharmacist’s shelf
2. Takes about 12 years
3. Five in 5000 drugs make it to clinical testing in humans
4. One in five of these make it to pharmacist’s shelf
5. Exception: AZT (Zidovudine) was approved in 1987 in
107 days to treat HIV.
HIV
AZT
Experimental Design to test the ability of Lipitor to
blood cholesterol levels in humans:
lower
Control – Patient group A eats a prescribed diet.
Variable – Patient group B eats same prescribed diet as
group A + they take 10 mg of Lipitor per day.
Results: At the end of the experimental period group A
has a higher blood cholesterol level than does group B.
Other variables that could be responsible for these results:
1. genetics
2. age
3. Exercise
4. Diet
White blood cell
What is Biology?
The study of Life.
What is Life?
Complex series of chemical
reactions carried out in a
complex physical structure called a CELL.
Bio-molecule
Why should we study biology?
1. Understand and appreciate natural world
2. Understand developments in medicine
and health
3. Understand environmental issues (natural
resources, pollution, global warming)
4. Understand human genome issues (stem
cell research, gene therapy)
5. Understand voting issues related to
science, medicine, environment, etc.
When is it Life?
When is it Non-Life?
Redwood forest is full of life - many species of
plants and animals living among the plants
Life
Pack or population of wolves
Life
An individual mountain lion
Life
Life
The circulatory system of an
animal represents life
Life
Life
Life
single heart cell
several heart cells
heart (an organ)
Life
Red blood cells
Non-life
Molecule
(hemoglobin)
Exam
Kingdoms of Life
all living things are included in one
of these 6 Kingdoms.
Life Defined
Complex physical state with a
complex series of chemical reactions.
Characteristics:
Acquisition and use of energy
Reproduction
Growth and development
Ability to respond to stimuli
Adapt to changing environment
High degree of organization
Homeostasis
Characteristics:
Section of an
unstimulated brain
Section of a
stimulated brain
Example - responding to stimuli
Acquisition and use of energy
Reproduction
Growth and development
Ability to respond to stimuli
Adapt to changing environment
High degree of organization
Homeostasis
All living things show basic similarities in
chemical make-up and chemical activities
Building block
molecules
(nutrients)
which are the
same for all
living things
Cell
DNA (blueprint)
Millions of
products can be
formed by a
finite number of
building block
molecules
Raw materials
(nutrients)
Blue print #1
(DNA genetic material)
Dog house
(product)
Tools
(enzymes)
Blue Print #1
(DNA)
Blue Print #2
(DNA)
Nutrients same
for all life
Enzymes
Human products
make human; dog
products make a dog
Blue print
(DNA) unique
to each
organism