Download Intro to Biology

Intro to Biology
Bio 9
CCSF
Lecture Outline
• Welcome & syllabus
• Intro to Biology
• The scientific method
Biology is the study of life
Biology has many subdisciplines
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Biochemistry
Cell biology
Ecology
Physiology
Microbiology
Genetics
Molecular biology
Population genetics
Botany
Agriculture
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Bioinformatics
Systems biology
Health
Medicine
Pharmacology
Evolution
Anatomy
Taxonomy
Paleobiology
Etc., etc., etc.
Biology from a human perspective
• Focuses on human body
• Biological principles and
their relevance to
human health, human
physiology, and the
human experience
• Environment, evolution,
and other biology topics
are also of significant
human interest
Biology is transforming our lives
• As available
biological
information
increases, our
knowledge of
biology advances
Biology is transforming our lives
• Antibiotics have saved
countless lives
• Antibiotics are part of a
constant war against
microbes
• The war isn’t over yet
Biology is transforming our lives
• Oscar Pistorius, South
Africa, 400m
• Fastest time: 46.25 sec
• World record: 43.18sec
• Cleared to compete in
the Olympics
• Didn’t compete (3rd at
S.A. Oly trials; but Oly
standard = 45.55)
Knowing Biology is a good way to get a
job
• Developments in
biological knowledge
have led to discovery of
new drugs
• Many drugs require
special manufacturing
procedures
• The bay area is a pretty
good place to get such a
job
Knowing biology is a good way to get a
job
• America has a rapidly
aging population
• Jobs in healthcare are
rapidly increasing
Knowing Biology is a good way to help
out
• Biology addresses many
needs and dangers the
earth and its
inhabitants currently
face
Knowing biology is a good way to
stay healthy through a long life
Knowing Biology can help you make
decisions about right and wrong
Knowing Biology can help you
avoid being deceived
Knowing Biology can stop crime
On a piece of paper
• Write the following
– Your name
– Where you’re from
– Guilty pleasure music
– The goals you have for CCSF
– How Bio 9 fits into those goals
• Share with your tablemates when you are
done
Biology and other sciences owe their
progress to the Scientific Method
Hypothesis testing
Experimental design
Clinical trials
There is no set “Scientific Method”
• Jane Goodall did not
conduct “experiments”
• Neither did Charles
Darwin
• Experiments are still
very important
• Two basic forms of the
scientific method:
• Discovery Science
• Hypothesis testing
The scientific method
Observations of interesting phenomena lead to a
hypothesis (educated guess) as to their causes
Predictions based on the hypothesis lead to
experimental tests
The scientific method
When results are obtained according to predictions, the
hypothesis is supported, and further predictions about
the hypothesis can be made
When results contradict hypothesis, the hypothesis is
rejected, and the hypothesis must either be revised or
discarded for a new one
LE 1-8a-1
Hypothesis
testing an
important
means by which
science
advances
Observations
Question
LE 1-8a-1
A good
hypothesis
must be
testable
Observations
Question
Hypothesis #1:
Dead batteries
Hypothesis #2:
Burnt-out bulb
LE 1-8a-3
A good
hypothesis
must be
falsifiable
Observations
Question
Hypothesis #1:
Dead batteries
Prediction:
Replacing batteries
will fix problem
Test prediction
Hypothesis #2:
Burnt-out bulb
Prediction:
Replacing bulb
will fix problem
Test prediction
While good
hypotheses
are always
falsifiable,
proving
them "true”
can be very
difficult
Observations
Question
Hypothesis #1:
Dead batteries
Prediction:
Replacing batteries
will fix problem
Test prediction
Test falsifies hypothesis
Hypothesis #2:
Burnt-out bulb
Prediction:
Replacing bulb
will fix problem
Test prediction
Test does not falsify hypothesis
Scientists record data using SI
(metric) units of measurement
In what way(s) is the science of
biology influencing and changing
our culture?
A) by providing new tools that can be used in
forensics
B) by revolutionizing medicine and agriculture
C) by helping us evaluate environmental issues
and the impacts of human actions
D) all of the above
E) none of the above
Does excess iron decrease growth?
• How can we test this?
Does excess iron decrease growth?
• How can we test this?
• How many groups should we
use?
• What size are the groups?
• How shall we create the groups?
• What is the
dependent/independent
variable?
Does excess iron decrease growth?
• How can we test this?
• How many groups should we
use?
• What size are the groups?
• How shall we create the groups?
• What is the
dependent/independent
variable?
• How would this experiment be
different if it were conducted
with people?
Good experiments are controlled
• Controls are references
which can be used for
comparison
• Experimental groupreceives treatment
(independent variable)
• Control group- does not
receive treatment
• Control variablesomething besides the
independent variable
which affects the outome
Experimental terminology
• Experimental group- group
receiving treatment in
question
• Control group- group not
receiving treatment
• Independent variable- the
treatment
• Dependent variableexpected measurable result
of treatment with
independent variable
• Sample size- number of
subjects in study group
• Positive control- a control
group created to resemble a
positive result
• Negative control- group
resembling a negative result
• Placebo- accounts for
human mind
• Double-blind- neither
patient (subject) nor doctor
(test administrator) knows
who is getting placebo
• Confirmation bias- The
tendency to view results
according to predictions
Clinical trials look at results in
people
Drugs must be proven safe by the FDA
• The drug approval
process is lengthy and
costly
• Usually costs $500m$1bn
• The drug is tested in vitro
first
• Then on cell culture flasks
• Then on animals
• Then clinical trials begin
Clinical trials on humans require
multiple phases
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Phase I: a small (20-50) group of
healthy volunteers determine
pharmacokinetics and
pharmacodynamics of drug
Anyone want to volunteer?
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Phase II: larger groups of actual patients
(20-300) and are designed to assess
how well the drug works
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Phase III: randomized controlled
multicenter trials on large patient
groups (300–3,000 or more) in
comparison with current 'gold standard'
treatment
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Phase IV: After drug is released to
public
Sometimes clinical trials are
outsourced to foreign countries
Critical thinking about experiments and their
results is a vital check to the scientific method
• Drug compaines often
suffer from confirmation
bias when they fund their
own studies
• Clinical trials are extremely
costly
• Successful drugs can be
extremely profitable
• Vioxx revenues: $2.5bn/yr
• Projected additional heart
attacks: 90,000-130,000
(~30-40% fatal)
Vioxx doubles risk of heart
attack compared to placebo
The scientific method has
advanced society
The scientific method is applicable beyond the
hard sciences
• Parents Grossly Underestimate The
Influence Their Children Wield
Over In-Store Purchases.
• 178 parents shopping with their
child in Austrian supermarkets
were unobtrusively observed while
strolling through the aisles…When
asked how many products their
children had made them buy, on
average parents only reported half
the number of purchases that had
been secretly observed.
Does excess iron decrease growth?
• How can we test this?
• How many groups should we
use?
• What size are the groups?
• How shall we create the groups?
• What is the
dependent/independent
variable?
• How would this experiment be
different if we used people?
"An athlete who uses dietary supplements will
perform better than one who doesn't." This
statement would be an example of which of the
following?
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A) Theory
B) Hypothesis
C) Skeptic
D) A haphazard statement
Defining life
Characteristics of life vs. nonlife
Biology is the study of life
Charles Darwin, Born Feb 12,
1809
HIV, with genes corresponding
to proteins
What is life?
• We know it when we
see it
• Characteristics not so
easy to define
• Some are more basic
than others
Life is orderly in a disorderly
universe
Seven important characteristics
common to living things
1. Macromolecular
composition
2. Cellular
structure
3. Growth and
reproduction
4. Use of energy
and materials
Seven important characteristics
common to living things
1. Response to
stimuli
2. Maintenance
of
homeostasis
3. Evolution
and
adaptation
1. All living things are composed of
4 common macromolecules
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Nucleic Acids
Proteins
Carbohydrates
Lipids
• DNA is a nucleic acid
2. Cellular structure
Unicellular- Bacteria, Archaea,
some protists
Multicellular- Eukarya: plants,
animals, fungi, other protists
3. Living things grow and reproduce
• Bacteria reproduce by
binary fission
• Daughter cells of
bacteria are nearly
identical
• But not quite…
• Sexual reproduction
ensures offspring are
different from parents
4. All living things utilize energy
and raw materials
The ultimate source for
energy for all ecosystems is
the sun
Humans and other animals
get energy & raw materials
from food
5. All living things respond to their
environment
6. All living things
regulate their
internal
environment
against external
changes
• Homeostasis- “staying
the same”
7. All life evolves across generations,
thereby adapting to its environment
• Variation in offspring
allows natural selection
• Variation in offspring
ultimately has its roots
in imperfect replication
of DNA
• Important noteIndividuals do NOT
evolve- populations
evolve
Natural Selection in the Peppered
Moth
• Same species, 2 variants
• Which one is better
adapted to its current
environment?
• What does the future
hold for this population
of moths?
Evolutionary history traces back to
a single origin for all known life
What is biology?
A) the study of life
B) the study of the environment
C) the study of genetics
D) DNA fingerprinting
E) the study of biomes
Major themes of biology
Classification
Evolution
DNA
Levels of organization
A primary goal of biology is
classification of life
• Living things are
primarily organized
according to ancestry
rather than similarity of
appearance
Life is organized into 3 major
groups called domains- Bacteria,
Archaea, and Eukarya
Within the Eukaryotes, there are 4 major kingdoms- Protists, Fungi,
Plants, and Animals
The unifying theme of biology is
evolution
• The evolution of
millions of species
belies the common
ancestry of all life
• Evolution: “change over
time”
-Natural
Selection is the
mechanism by
which
populations
evolve
- “Survival (and
reproduction) of
the fittest”- those
which best fit
their environment
Population with varied inherited traits
Elimination of individuals with certain traits
Reproduction of survivors
Figure 1.15b
The increasing prevalence of antibiotic –
resistant pathogenic microbes is an example
of evolution by natural selection in action
Scientists seek to classify life
according to its common ancestry
All living things have DNA
• DNA is an orderly, selfreplicating molecule
• DNA stores all genetic
information
• It does not reproduce
itself perfectly every
single time…
• As DNA evolves, living
things evolve
Changes in DNA are called
mutations, and can be inherited
• When DNA is changed,
proteins change
• Ear proteins in cats can
cause curled ears
LE 1-1a
Biosphere
Ecosystem
Florida coast
Life can be studied
at many levels
Community
All organisms on
the Florida coast
Population
Group of brown
pelicans
Organism
Brown pelican
LE 1-1b
Organism
Brown pelican
Spinal cord
Nerve
Organ system
Nervous system
Brain
New properties
emerge at each new
level of complexity
Organ
Brain
Tissue
Nervous tissue
Cell
Nerve cell
Nucleus
Organelle
Nucleus
Atom
Molecule
DNA
Which of the following is not a
characteristic of all living things?
• A) They are composed of multiple cells.
• B) They respond to stimuli.
• C) They contain organic molecules such as
carbohydrates, proteins, lipids, and nucleic
acids.
• D) They have adaptive traits.