Transcript Biology Today (BIOL 109)

Biology Today
(BIOL 109)
Biology with an Issues
approach
What is Life?
– “Life is a multifaceted concept with
no simple definition
……”
– Building LEGOs and
playing “soccer” with Mazz
Quinn DelVal (age 11)
– Life is a live album
by Irish band Thin
Lizzy
Scientists at work
• Biologists are NOT geeks!
• Some work in a lab, others
collect data in the field.
• There are many “branches”
of biology
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Plant Biology
Ecology
Human Biology
Biochemistry
Genetics
Molecular Biology
The Scientific method
• Animals, Plants, and Bacteria are complex and
variable
• At any moment living systems may differ in external
conditions, internal conditions, or in the way in which
these conditions interact
• The same individual is not the same from one day to
the next.
• Need to study more than one individual (say 100) and
collect average data
• Look out for variation!!!!!!
The Scientific method
The Scientific method
• Scientists use the Scientific Method to test
Theories.
– Generate an Observation
– Pose a Hypothesis
– Perform Experiments
– Analyze Results
– Reach a Conclusion--does the date support or
refute our Theory?
Why do Experiments in Labs?
• Controls! Controls! Controls!
• Lab Experiments can prevent “variables”
– Variable: Factor that can cause observable change
and through results off.
• Independent – what you vary during the experiment.
Usually this will be time.
• Dependant – what you measure – what will change
during the experiment
– Control: Subject to all experimental steps EXCEPT
the experimental Factor.
The Experimental Approach!
• Lederbergs experiments on bacterial genetics
• Most bacteria are killed by streptomycin
• The Lederbergs exposed E. coli to streptomycin and
were able to isolate streptomycin-resistant E. coli
strains.
• They allowed these bacteria to reproduce and showed
that resistance to streptomycin was inherited by
their offspring
The Experimental Approach!
• This gave the Lederbergs two hypothesis to test
– The mutation was caused by exposure to streptomycin
– Bacteria mutated before exposure to streptomycin
So they conducted an experiment to test both of these
hypotheses.
Figure 1.3 (1)
Figure 1.3 (2)
Figure 1.3 (3)
Figure 1.3 (4)
Scientific theories
• Animals, plants, and bacteria are examples of living systems
that share many properties distinguishing them from nonliving
things. These properties are branched into theories.
Cellular organization
Fundamental unit of life is the cell – all living things are
made up of cells.
Metabolism
Living things take up energy-rich materials and give out
waste to environment. Some energy fuels life processes
some accumulates and is released after death.
Selective response
Living things respond selectively to stimulation in the
environment. Organisms recognize certain chemicals as
nutrients while ignoring others.
Scientific theories
Homeostasis
Living systems have some capacity to change harmful
conditions into conditions more favorable to their continuing
existence – the conversion of chemical compounds.
Growth and biosynthesis
Living systems go through phases during which they make
more of their own material.
Genetic material
Living systems contain genetic material (DNA and RNA) to
allow inherited traits.
Reproduction
Living systems can reproduce & pass on genetic material.
Population structure
Organism form populations. Of these organism capable of
sexual processes, a population is all those organisms that
can interbreed with one another.
Paradigms
• A paradigm is much more than a theory
– It includes a strong belief in the truth of one or more theories
and shared opinions as to what problems are important and
unimportant
– What techniques and research methods are useful
• Over time a paradigm shift occurs
– Better technologies and scientific instruments lead scientists
to look and old data in a different way
– Younger scientists look at old data in a new way
– In this way ideas and definitions of theories alter over time
an new data is collected and explained.
Paradigm Shifts
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OLD PARADIGM
Natural Theology, Lamarckism, and
several other competing paradigms
Blending inheritance and various folk
ideas
Various beliefs: bad humors, bad air or
water, evil spirits, and many others
Competing paradigms, including
Darwinism, mutationism, population
genetics, neo-Lamarckism
Classical Mendelian genetics
Various theories of territorial behavior,
sexual behavior, etc.; also
psychological theories (gestalt,
behaviorism, ethology)
Descartes’ mechanistic theories and
dualism
Classic germ theory: pathogenicity as a
characteristic of pathogen only
NEW PARADIGM
Darwinism (since 1859)
Classical Mendelian genetics (since 1865
or 1900)
Germ theory of disease (Pasteur, Koch,
since 1880)
Modern evolutionary theory (since 1940)
Molecular genetics (since 1950s)
Sociobiology (since 1975)
Mind–body connections (since 1980s)
Pathogenicity as an interaction of
pathogen and host (since 1990s)
Science has Improved our
Lives!
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Antibiotics--Penicillin, others?
Vaccines--Polio, Measles, Smallpox, others?
Cell Biology--Cancer Research, others?
Genetics--Basis for Disease, others?
Physics--Electricity!, others?
Engineering--Roads, Bridges, Buildings,
Planes, Trains, Bikes, others?
• Fermentation--Civilization!
Science has also opened up
“Pandora’s Box”
• Bio-warfare-, Anthrax letters, Current
worries?
• Nuclear Weapons--Does North Korea
really have them?
• Genome--Insurance issues, Selecting
offspring?
• Others?
Ethics and Information
• One of your roles in our society is to help
determine how future technologies should
be used and regulated.
• To make the best decision possible, you
need to be informed!
• My Goal is to help you to become
informed!
Ethical thinking
• Ethics is a discipline
dealing with the analysis of
moral rule and the ways in
which moral judgments are
made and justified.
• Would you park your car in
this space?
• Why?
Ethical thinking
• What benefits could come
from nuclear power?
• At what cost?
• At what risk?
• Remember Chernobyl?
Chernobyl Nuclear Disaster
• April 26, 1986 in the Ukraine,
• It is regarded as the worst accident
in the history of nuclear power.
• A plume of radioactive fallout drifted
over parts of the western Soviet
Union, Eastern and Western
Europe, Scandinavia, the British
Isles, and eastern North America.
Large areas of Ukraine, Belarus,
and Russia were badly
contaminated
• Resulted in the evacuation and
resettlement of over 336,000
people. About 60% of the
radioactive fallout landed in
Belarus, according to official postSoviet data
Chernobyl Nuclear Disaster
• Two hundred people were hospitalized
immediately, of whom 31 died (28 of them
died from acute radiation exposure).
• Most of these were fire and rescue
workers trying to bring the accident under
control
• At least 8,000 people have died, most
from radiation-related diseases.
• About 2,000 people have been diagnosed
with thyroid cancer and between 8,000
and 10,000 cases are expected to
develop over the next 10 years.
Ethical thinking
• Do animals have rights?
• Nearly all new drugs,
cosmetics, food additives, new
forms of surgery are tested on
animals first
• Many societies have historically
denied even the most basic of
rights to classes of persons on
the basis of economics,
gender, race, ethnicity, or
religious beliefs
Ethical thinking
• Humans as experimental subjects
• 1932 The Tuskegee Syphilis Study begins. 200
African-American men infected with syphilis are
never told of their illness, are denied treatment,
and instead are used as human guinea pigs in
order to follow the progression and symptoms of
the disease. They all subsequently die from
syphilis, their families never told that they could
have been treated.
• Voluntary informed consent
– Both a moral and legal issue
• As there are lawyers under every rock!
Ethical thinking
• Gender bias
– What happens if this is not
considered
– It was only in 1992 that women
were included in medical trials
of new drugs by law!
• Thalidomide (Kevadon®)
– Developed as a morning
sickness drug in the 1950s
– BUT – never tested on women
• Led to a generation of
deformities
Ethical thinking
• In UK alone there were 12,000
victims.
• Sometimes functional feet and
hands were amputated to allow
the fitting of lower- and upperlimb Prosthesis in order for the
children to appear “normal”.
• Special school were set up too,
in an attempt to keep the
children out of sight and out of
the minds of the public.
Ethical thinking
• Victims of the 1970s
Thalidomide scandal have
passed their deformities on
to their children.
• Turns out that Thalidomide
altered the DNA of the
victims – so arms and legs
are not developed!
Ethical thinking
• Still in use today
• Cancer treatments
– by cutting off the flow of blood to
tumors
• Leprosy
– is an infectious disease caused by
a DNA plasmid
– invades human nerves.
– If untreated can eventually cause a
variety of skin problems, loss of
feeling, and paralysis of the hands
and feet
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