Biology is Relevant
Why Study Biology?
• Great advances
Biology is relevant
– 19th & 20th centuries
• Disease caused by pathogens
– Great advances
– Bioengineering
– Population has grown
– Emerging technologies
– Today
• Emphasis turning to physiological
malfunctions
– Past diseases fatal – now treated
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ANTIBIOTIC RESISTANCE:
Superbugs on the Hoof?
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Biology is Relevant
Dan Ferber, Science 2002
• Bioengineering
Disturbing new findings have provided a key link in the chain of evidence
connecting antibiotics used on livestock to outbreaks of disease caused by
antibiotic-resistant human pathogens
– New Green Revolution
When the severe diarrhea didn't stop after nine awful days, the 62-year-old Danish
woman dragged herself to the emergency room at Bispebjerg Hospital in
Copenhagen. The diagnosis was a cinch: food poisoning from Salmonella. Doctors
rolled out their big gun, an antibiotic called ciprofloxacin that can vanquish the
nastiest Salmonella strains in a few days. But as the hours passed, the infection
worsened-- becoming so bad that the Salmonella punched a hole in her colon,
allowing it and other bacteria to invade the rest of her body. As the situation grew
desperate, doctors blasted her with heavy doses of two more antibiotics and stitched
up her damaged colon. The drugs knocked off the Salmonella, but other escapees
from the gut sent her into septic shock; one by one, her organs failed. Four days after
doctors realized the Salmonella was impervious to ciprofloxacin, she was dead.
• Developed new corn plant varieties
• Genetically enhanced
– Resist pests & drought, cold tolerant
– Could help alleviate world hunger
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Scientists Now Acknowledge Role of
Humans in Climate Change
Biology is Relevant
By ANDREW C. REVKIN October 26, 2000, NY Times
Greenhouse gases produced mainly by the burning of fossil fuels
are altering the atmosphere in ways that affect earth's climate, and it
is likely that they have "contributed substantially to the observed
warming over the last 50 years," an international panel of climate
scientists has concluded. The panel said temperatures could go
higher than previously predicted if emissions are not curtailed.
• Population growth should level in 21st
century
– Leveling will not be easy or quick
– Tough decisions – couples, nations,
beyond
– Where put new cities, farms, etc.?
This represents a significant shift in tone — from couched to
relatively confident — for the panel of hundreds of scientists, the
Intergovernmental Panel on Climate Change, which issued two
previous assessments of the research into global warming theory, in
1995 and 1990.
– Monitor & manage existing wild areas
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Biology is Relevant
Biology can be Controversial
• Some controversial questions:
– Family planning – birth control?
– How much $ to spend – endangered
species?
– Biomedical research – human fetal
tissue ethical?
• Emerging technologies – computers
– Will bridge gap between biology &
technology
– New career opportunities
• Biotechnology (lab-oriented)
• Applied technology (field-oriented)
• Some will straddle lab & field
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Youth's Death Shakes New Field of Gene
Experiments on Humans
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Biology can be Controversial
By SHERYL GAY STOLBERG, January 27, 2000, NY Times
WASHINGTON, Jan. 26 -- Perhaps no event in recent medical
history has done more to shine light on the inherent conflict of
interest between researchers and their subjects than the death of an
18-year-old from Tucson in a gene therapy experiment at the
University of Pennsylvania.
It has been four months since Paul Gelsinger made the wrenching
decision to withdraw life support from his son, Jesse, after an
infusion of gene-altered viruses meant to correct an enzyme
deficiency caused an immune response that spiraled out of control.
The grieving father then vowed to stand by the Pennsylvania
scientists "until my dying day."
• Controversial questions:
– Irradiated food safe to eat?
– Dangers cloning animals? Humans?
– Are we playing God?
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Chefs Join Campaign Against Altered Fish
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Biology can be Controversial
By MARIAN BURROS September 18, 2002, NY Times
• Some controversies remain within
biology
• Others involve economic, moral,
ethical & religious considerations
• Biology can help understanding
In a pre-emptive strike against the newest genetically engineered food, 200 chefs,
grocers and seafood distributors across 40 states plan to announce today that they
have pledged not to purchase fish that have been altered through biotechnology.
The campaign says it is concerned that if genetically engineered salmon are
approved by the Food and Drug Administration, they could escape from the pens in
which they are raised and interbreed with wild salmon, endangering some species.
The F.D.A. is considering an application to market transgenic salmon. If the
application is approved, salmon would become the first genetically modified animal
allowed onto American dinner plates, where it would sit alongside genetically
engineered corn and potatoes, which have been available for several years.
– Identify options
– Describe impacts
The biotech company producing the salmon says they will be better for the
environment than current farmed salmon.
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British Scientists Seek Approval to Clone
Human Embryos
Biology
By THE ASSOCIATED PRESS August 16, 2000, NY Times
LONDON -- A panel of experts urged the government to allow human
cloning for scientific study of transplants, a recommendation that, if
approved, would make Britain the first country in the world to authorize
human cloning for any purpose.
• The study of life
– A way of understanding nature
– A human endeavor
In calling for Britain to amend its ban on human cloning, the governmentcommissioned panel said scientists should be allowed to create cloned
embryos to study the manufacture of cells and tissues for transplant.
• Strives to …
The government accepted the panel's recommendation, led by Britain's
chief medical officer, and said it would initiate legislation to implement it as
soon as possible.
Ethical concerns have tempered many countries' consideration of cloning
technology.
– Understand,
– Integrate, and
– Describe
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What is Life?
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What is Life?
• Difficult to define
• Biologists focus on how life works
• Living organisms
– Highly organized, complex entities
– Composed of one or more cells
– For Biologists, life is:
• Contain a blueprint of characteristics
• That set of characteristics that distinguish
living organisms from
• Inanimate objects
– Acquire and use energy
– Carry out and control numerous chemical
reactions
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What is Life?
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What is Life?
• Living organisms
• Living organisms
– Grow in size and change in appearance and
abilities
– Maintain constant internal environment
– Produce offspring similar to themselves
– Respond to changes in environments
– May evolve into new types of organisms
• Living organisms possess all of these
simultaneously
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cells
The diversity of life
nerve cell
tissues
nervous tissue
organs
• A. The three domains of life
the brain
– 1. Bacteria
– 2. Archaea
pronghorn antelope
– 3. Eukarya
organisms
populations
herd of pronghorn antelope
communities
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snakes, antelopes, hawks, bushes, grass
The diversity of life
•
•
Biology: A Branch of Science
• Science is a way of knowing the natural
world
B. The importance of biodiversity
C. Evolution—the unifying concept of
biology
–
–
– Science is an activity
• It’s what scientists do
– Body of knowledge derived from that activity
1. Genetic variation and inheritance
2. Natural selection
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Biology
Biology: A Branch of Science
• Biology also differs from Science
• Integrated with other sciences
– Younger
– Organisms subject to laws of physics and
chemistry
– Mathematics used to analyze & interpret
biological data
• Natural science studied for 1000s of years
• Physics since the 1500s
– Modern Biology
• Began with Darwin – mid 1800s
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Major Theories of Biology
Evolution by Natural Selection
• Theory has two parts
•
•
•
•
•
•
•
Evolution by natural selection
Inheritance
Cells
Biological Classification
Bioenergetics
Homeostasis
Ecosystems
– Species change over generations
– Natural selection is mechanism for change
• Accepted by many scientists as Biology’s
most important theory
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Inheritance Theory
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Inheritance Theory
• Inheritance – intimately connected with
evolution
• How are traits inherited by offspring from
parents?
• Mendel’s principles of inheritance
apply to all organisms
– Traits passed from one generation to next
via hereditary factors (genes)
– Mendel’s published results
– Gregor Mendel’s pea plants
• Ignored at first in 1865
• Rediscovered early in 20th century
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Biological Classification
Cell Theory
• Matthias Schleiden & Theodor Schwann
proposed Cell Theory
• Started much earlier than most
– Carolus Linnaeus – late 18th century
– Elements of Cell Theory
• Classified living organisms by
– Similarities
– Differences
• All organisms are composed of cells
• All cells come from pre-existing cells
• The cell is smallest unit capable of exhibiting all
characteristics of life
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Bioenergetics
Bioenergetics
• The energy that powers life
• Operates according to rules that govern
energy
• Antoine Laurent Lavoisier, late 18th
century
– Placed chemistry of life into
– Antoine Laurent Lavoisier, late 18th century
• Larger context of physics & bioenergetics
• Culminated in understanding chemical
reactions of cells (metabolism)
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Homeostasis
Ecosystems
• Organisms interact with each other & their
environment
• Changes in biological community can alter
other parts
• Claude Bernard – mid 19th century
– Organisms function best when
• Internal conditions maintained in narrow
limits
– External toleration via stable internal
conditions (organisms)
– Stability (homeostasis) maintenance
constitutes study of physiology
– Ecosystem concept
• Recognizes organisms do not exist alone
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Ecosystems
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How is Biology Studied?
• Five Key Words of Biologists
• Youngest of biology’s major ideas
– Product of 20th century
– No readily identifiable parent
– Diverse group of specialists
– Perhaps most complex of concepts
Observation
Questioning
Hypothesis
Testing
Explanation
• Blends biology & other sciences
– Backbone of ecology
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Scientific Method – How?
The Scientific Method
• Observation
– Can be something entirely new
– A new way of looking at things, or
– A realization natural world is at odds with
currently accepted ideas
– Leads to questions
The set of procedures that form that
rational approach to studying the
natural world
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Scientific Method – How?
Originally,
this greenish
bacterial
growth
covered the
entire petri
dish.
• Questioning – some science do not
address and can’t
– Scientists ask
• Questions answered by experiment or observation
of material universe
When an
experimenter
placed a
penicillincoated disk
of paper in
the dish,
nearby
bacteria were
killed.
– Biologists use
• Observation & experience to ask how or why
something happens
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Scientific Method – How?
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Scientific Method – How?
• Hypothesis – tentative explanation,
possible answer
• Hypothesis – tentative explanation,
possible answer
– In formulating hypotheses, scientists
– In formulating hypotheses, scientists
• Believe events & phenomena of material
world have causes
• Believe simplest explanation is preferred
(Occam’s razor)
• Accept world as real place
• Believe world is neither chaotic nor
dependent upon
– Supernatural realm
– Metaphysical realm
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Scientific Method – How?
Testing
• Systematic observations
• Controlled experiments
• Detailed studies used to test hypotheses
• Hypothesis
– Always tentative & remain so until
rigorously tested
– A scientist should be ready to abandon
when
• A better one
• More consistent with observation is proposed
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Testing
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Explanation
• Occupies most of working scientist’s time
• Begins when
• A mature hypothesis, one that has been
tested
• All explanations subject to review &
reconsideration when
– Scientist makes logical predictions
– Based on hypothesis
– New evidence is presented
– Better explanations are proposed
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Explanation – Theory
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Explanation – Theory
• Nonscientists believe a theory is
• Many explanations in Biology are
considered true
– Pure speculation
– Without practice or evidence
• Scientists consider a theory a
– Demonstrable, or
– Well established principle
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