Download BIOL 103 – What is science?

BIOL 103 – What is science?
Sierra Club:
Cato Institute:
Global warming will bring
drought, famine
Global warming is “No
urgent danger”
How do you decide what to do?
2
Today’s Questions
What kinds of questions do
scientists answer?
How do scientists answer
questions?
How are scientific discoveries
disseminated among
scientists.
How can you evaluate whether
scientists are right?
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1. Which of these are scientific questions?
Climate change questions:
Is the earth warming?
Have humans caused the earth to warm?
Should we use more solar energy?
How will CO2 emissions affect the climate of Africa?
Should more windmills be built in Montana?
Is China producing too much pollution?
Wolf management questions:
Should we allow wolves to live in Montana?
How many elk will wolves in the Yellowstone region kill?
Is it wrong to kill a wolf to protect cattle?
What affects do wolves have on an ecosystem?
Should wolves be hunted in Montana?
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Science describes and explains the natural world
It does not tell us what is good or bad.
It does not tell us what we should to.
Climate change questions
Is the earth warming?
Have humans caused the earth to warm?
Should we use more solar energy?
How will CO2 emissions affect the climate of Africa?
Should more windmills be built in Montana?
Is China producing too much pollution?
Wolf management questions:
Should we allow wolves to live in Montana?
How many elk will wolves in the Yellowstone region kill?
Is it wrong to kill a wolf to protect cattle?
What affects do wolves have on an ecosystem?
Should wolves be hunted in Montana?
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Like many (most?) environmental
controversies, wolf management is
more about values than science
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This mans that science won’t resolve many of
environmental conflicts
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An interesting thing about values
is that sometimes they change
Some of the values of previous
generations horrify us.
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American women couldn’t vote until 1920
Not too long ago, marriage vows required women to
“love, honor, and obey” husbands
Women campaigning for the right to vote in Havre, MT
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Examples of changing values: Grand Canyon
“I cannot conceive of a more worthless impracticable region.”
—John McComb (1859)
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Some things we do today may appall
future generations
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2. Possible ways to answer questions
1. Believe what makes
“sense” (i.e. what is
logical).
2. Believe a respected
authority.*
*This is the method used by my 3
year old daughter.
Plato and Aristotle
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An example of this at work…
Aristotle wrote that:
Heavy objects logically
should fall faster than
lighter ones. Therefore
they do.
For 2000 years, scholars
believed him because he
was an authority.
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…Until Galileo, “father of modern science”*,
conducts an test (~1600)
… and observes
that heavy
objects DON’T
fall faster.
*According to Einstein
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Science uses LOGIC but is ultimately based on
OBSERVATIONS
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How do scientists answer questions?
The “scientific method” of course!
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Scientific
thinking at work:
Did a meteor kill
the dinosaurs?
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The meteor hypothesis
• Massive meteor strikes earth
• Forests around earth burn
• Smoke & dust obscure sun
around earth
• Plants die
• Animals die
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Testing ‘meteor’ hypothesis
The ‘Hell Creek’ Formation of central Montana has lots of
dinosaur fossils.
How could WE use these rock layers to test the hypothesis
dinosaurs were wiped by a meteor impact.
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Logic behind one way to
start to answer dinosaur extinction
IF
Dinosaurs were driven extinct by a meteor
AND
The distribution of dinosaur fossils in rock
layers are examined
THEN
Dinosaur fossils will disappear from rock
layers abruptly
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Dinosaurs fossils do end abruptly in rock layers
NO dinosaur fossils in this layer
Dinosaur fossils in this layer
This supports claim meteor killed dinosaurs
Each part of this argument has a name
IF
hypothesis
Dinosaurs were driven extinct by a meteor
AND
The distribution of dinosaur fossils in rock
layers are examined
THEN
Dinosaur fossils will disappear from rock
layers abruptly
test
prediction
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Hypothesis
A potential explanation
Prediction
What will be observed in a test if a
hypothesis is true
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Does this prove meteor killed off dinosaurs?
NO dinosaur fossils in this layer
Dinosaur fossils in this layer
No. Perhaps massive volcanic eruption killed
off dinosaurs very quickly
NO dinosaur fossils in this layer
Dinosaur fossils in this layer
Fact: Meteors have a high concentration of
iridium, volcanoes don’t
Make another prediction for the hypothesis
dinosaurs were killed by a meteor
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Testing meteor hypothesis
IF
hypothesis
Dinosaurs were driven extinct by a meteor
AND
test
We examine the amount of iridium in rock
layers formed near dinosaur extinction
THEN
There should be high levels of iridium at time
of extinction
prediction
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Rock layers at dinosaur extinction
NO dinosaur fossils in this layer
Younger rocks
High levels of iridium in this layer
Dinosaur fossils in this layer
Older rocks
Have we proved it now?
NO dinosaur fossils in this layer
NO dinosaur fossils in this layer
High levels of iridium in this layer
Dinosaur fossils in this layer
Dinosaur fossils in this layer
No. Maybe there was a meteor and a volcano eruption at
nearly the same time, and it was the volcano that killed
dinosaurs.
Volcanic eruptions in India (Deccan traps) may
have contributed to dinosaur extinctions
These are the most extensive
lava flows on earth.
Gas from eruptions
disrupted global climate.
Volcanic eruptions and
asteroid appear to have
occurred at almost same
time.
Identifying which caused
dinosaurs to go extinct
difficult.
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How to earn cheap points in an argument.
Ask:
Have scientists
proved that?
• The answer is always “No.”
• A hypothesis may be supported or very well supported,
but…
• Scientists never prove anything.
• Scientists must remain open to the possibility that
future research will produce evidence a different
hypothesis is correct.
• We might say, however, that something is “proven
beyond a reasonable doubt.
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Warning!
Every year many students get confused
regarding what is a hypothesis
A hypothesis is NOT what you think will be
observed in a test. It is an explanation for
what causes something.
A prediction is NOT what you believe is true
or will happen. It is what will be observed
in a test or experiemnt if the hypothesis is
true.
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Thought question
Is a hypothesis an “educated guess?”
Not really.
A hypothesis may be an “educated guess”, but not all educated guesses are hypotheses.
A guess is usually a statement about what a person believes will happen, but a scientist
can formulate and test a hypothesis without believing it to be true, or making a personal
prediction about what will happen in an experiment.
“…teachers of science in primary schools have often simplified the meaning
of the term "hypothesis" by describing a hypothesis as "an educated
guess". The failure to emphasize the explanatory or predictive quality of
scientific hypotheses omits the concept's most important and characteristic
feature: the purpose of hypotheses. People generate hypotheses as early
attempts to explain patterns observed in nature or to predict the outcomes
of experiments.”
- Wikipedia
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Practice question
Many species of frogs and other amphibians around the
world are gradually dying out. Some scientists have proposed
this is caused by increased amounts of ultraviolet radiation
from the sun. In particular, ultraviolet radiation may damage
amphibian eggs while they incubated in shallow ponds. In
order to test this idea, scientists installed sunshades over
ponds and recorded the survival rate of frog eggs that were
either under these shades (and protected from radiation) or
not.
What is the hypothesis?
What is the test?
What is the prediction?
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Testing ultraviolet radiation hypothesis
IF
hypothesis
Ultraviolet radiation is harming amphibians
AND
Sun shades are installed over ponds
test
THEN
Frog eggs under shades will survive more often
than eggs not under shades
prediction
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Potential quiz next class
Be able to define
and identify:
hypothesis, test,
prediction
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Practicing scientific thinking
We all know that if we go into our backyard and drop a variety of objects, some
light objects, such as feathers, fall slower than heavy objects, such as rocks.
This contradicts Galileo’s conclusion that all objects fall at the same rate.
Come up with a hypothesis that explains this discrepancy.
Propose an experiment that could test this hypothesis.
Write out the hypothesis, test, and prediction
Then watch the movie at one of the links below to see experiment that resolves
this question:
http://nssdc.gsfc.nasa.gov/planetary/lunar/apollo_15_feather_drop.html
http://www.youtube.com/watch?v=5C5_dOEyAfk (or search for ‘Apollo feather
drop’)
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3. Communicating scientific research
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Scientific results are published in specialized journals
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Selected journals publishing
research on fish
Fish Biology
Fisheries
Canadian Journal of Fisheries and Aquatic Sciences
Journal of Aquatic Animal Health
Transactions of the American Fisheries Society
North American Journal of Fisheries Management
Fish Physiology
Fish Physiology and Biochemistry
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Journals publishing climate science research
Reviews of Geophysics
Annual Review of Earth and Planetary Science
Climate Dynamics
Journal of Geophysical Research (JGR)
JGR – Atmospheres
JGR – Biogeosciences
JGR - Earth Surface
JGR – Oceans
JGR - Space Physics
Bulletin of the Amer. Meteorological Society
American Journal of Science
Earth Science Reviews
Paleoceanography
Global Biogeochemical Cycles Journal of Climate
International Journal of Climatology
Theoretical and Applied Climatology Climate Research
Earth Interactions
Geophysical Research Letters
Quarterly Journal of The Royal Meteorological
Society
Philosophical Transactions of the Royal Society
Earth and Planetary Science Letters Geophysical Journal International Meteorology and Atmospheric Physics
Journal of the Atmospheric Sciences Journal of Applied Meteorology and
Climatology
Global and Planetary Change
Global Environmental Change
Atmospheric Environment
Atmospheric Chemistry and Physics
Physics and Chemistry of the Earth, Part A
Boundary Layer Meteorology
Atmospheric Science Letters
Advances in Atmospheric Sciences
Past climates
Quaternary Science Reviews
Climate of the Past
Journal of Quaternary Science The Holocene
Palaeogeography, palaeoclimatology,
palaeoecology Radiocarbon
Oceanography
Journal of Physical Oceanography - publisher:
American Meteorological Society
Oceanologica Acta
Atmosphere - Ocean - edited by Canadian
Meteorological and Oceanographic Society,
Terrestrial, Atmospheric and Ocean Sciences
Journal of Forameniferal Research Marine Geology
Marine Chemistry
Journal of Marine Systems
Glaciology and polar studies
Journal of Hydrology
Annals of Glaciology
International Journal of Glaciology The Cryosphere
Polar Research Journal
Boreas
Physical Geography Geology
Physics of the earth and planetary interiors
Geological Society London Special Publications
Geochimica et Cosmochimica Acta
Australian Journal of Earth Sciences Exploration Geophysics
Reports on Progress in Physics
Earth Interactions
Tectonophysics
Journal of Atmospheric and Solar-Terrestrial
Physics
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Journal Article is Unit of
Scientific Progress
“An improved method for estimating inbreeding
depression in pedigrees”
- Zoo Biology
“Inbreeding depression in captive bighorn sheep”
- Animal Conservation
“No inbreeding depression observed in Mexican and red
wolf captive breeding programs”
- Conservation Biology
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Scientific papers has same format
as lab reports in science class
Introduction
Explains what will be studied and why it
is important.
Methods
Describes how the study was performed.
Results
Presents what was observed.
Discussion
Discusses the significance of the results.
Suggests future work.
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Scientific papers are full of charts and
tables that summarize the data collected
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All claims in scientific papers must be supported
by either data or references to other papers
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Classroom exercise Question#2
Scientific journals are managed by editors
whose job it is to decide what scientific
papers to publish. How does an editor
decide whether a paper is accurate
enough to be published?
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Will the following students please
see me before class?
Samuel Bemmim
Sydney Bogden
Samantha Smith
Stefanie Serrera
Parker Thorton
Trevor Waller
Don’t worry: You are not in trouble
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Review
What is
hypothesis,
test, prediction?
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Testing boiling river hypothesis
IF
hypothesis
We were on the boiling river trail
AND
We looked at hikers coming other way
test
THEN
Those hikers should have wet hair, towels, or
other signs of soaking in a hot spring
prediction
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How science works in practice:
The peer review process
Most scientists regarded the new
streamlined peer-review process
‘quite an improvement.’
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The peer review process
1. Author submits paper to journal.
2. Editor of journal gives paper to
associate editor with expertise in
specific subject.
3. Associate editor asks 2 - 3 experts
(peers) to read paper and write an
anonymous review of the paper.
4. If reviews are positive, the editor
will publish paper. If reviews are
negative, the editor may reject the
paper or ask for revisions.
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An example of a request for peer
review
Dear Dr Kalinowski,
I'm writing as an associate editor of the journal Conservation Biology. We've received a paper
entitled "Modeling Misidentification Errors that Result from Use of Natural Tags in CaptureRecapture Studies" by Yoshizaka et al. I was wondering if you would be prepared to review
the paper for us, as I think it is close to your research interests?
I have pasted the abstract below. If you're able to review it, I'll send you the manuscript as an
e-mail attachment.
Thank you very much for your help, and I do hope you are able to review this paper for us.
Best wishes,
E.J. Milner-Gulland
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Peer Review:
An example
Manuscript
“Competitive interactions between Age-0 Bighead carp and
Paddlefish”
Authors
Amy Schrank & Christopher Guy
MSU Dept of Ecology
Journal
Transactions of the American Fisheries Society
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Competition between
Native and Newcomer?
Carp
Recently introduced from China
Paddlefish
Montana native
65 million years
http://fwp.mt.gov/fishing/fishingmontana/brochure_paddlefish.html
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Carp and paddlefish both eat the same size plankton,
so competition seems likely.
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Experimental Design
Place 5 paddlefish & 5 carp in net pens
Regularly feed fish plankton
Check weight 1 month later
5 Paddlefish
5 Carp
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Testing for paddlefish / carp
competition
If
Competition with carp is bad for paddlefish
And
Both species are placed in a confined pen
Then
Paddlefish should not grow well
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Result: Paddlefish lose weight
Does this demonstrate competition with
carp hurts paddlefish?
5 Paddlefish – 17%
5 Carp
+2%
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Result: Paddlefish lose weight
Does this prove competition with carp
hurts paddlefish?
No. Maybe paddlefish
were stressed by the
nets, over crowding, bad
weather, or something
else.
Paddlefish
– 17%
5 Carp
+2%
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Experiment also had pen with just
paddlefish.
Paddlefish -17%
Carp
Paddlefish -11%
+2%
Now what do you conclude?
Would you publish the paper?
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Associate Editor’s Comments
“[This paper] reports a potentially interesting set of
experiments addressing an important question…
However, there are some weaknesses with the
experimental design… that limit its usefulness...”
“The invertebrate prey additions complicate evaluation
of the responses of both the invertebrate prey
abundance and fish growth. Mesocosms are typically
used to represent natural conditions on a small scale, but
continually adding organisms... complicates matters
greatly. “
Paper REJECTED
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The author’s response
Dr. Guy wrote a letter to
the head editor (who was
his friend, and the
associate editor’s boss)
and argued that his paper
was not being treated
fairly. The editor reversed
the associate editor’s
decision and the paper
was published.
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Does this mean peer-review is useless
and science unreliable?
No.
Peer-review is not perfect, but that doesn’t mean it isn’t
valuable.
Anecdote should show give you reason to not place too
much faith in any single scientific paper.
I would be more likely to believe carp hurt paddlefish if
multiple studies performed by different scientists in
different ways reached the same conclusion.
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Peer Review
(instructor’s opinion)
Faulty at times (it is, after all, a
human endeavor)
Improves quality of science
Helps keep science
trustworthy
See Wikipedia for a nice article on how peer review works.
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A humorous take on peer review:
Hitler as a scientist receiving peer reviews
http://www.youtube.com/watch?v=-VRBWLpYCPY
Warning: video contains foul language.
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Why all the fuss about peer review?
Michael Moore, filmmaker
Rush Limbaugh, talk show host
When deciding who to believe, you might want to consider that politicians
and media figures do not have to support their claims with data, or have
their conclusions checked for accuracy.
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4. How can you and I recognize good
science…?
…when I couldn’t even demonstrate that the earth
goes around the sun.
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Congress uses the
National Academy of
Science to review
important questions
(e.g. global warming)
These are the most
accomplished scientists
in the country
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You and I can use Carl Sagan’s
Baloney detection kit
A checklist for non-experts to evaluate scientific claims.
1. Peer reviewed journal?
2. Is the data shown? Results
clear?
3. Work replicated?
4. Consensus in community?
5. Does claim make sense?
6. Alternatives considered?
7. Who provided funding?
8. Is there an agenda?
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Percentage of peer reviewed scientific
papers that accept anthropogenic
climate change
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A third “scientific method”:
Debate among scientists
1. IF / AND / THINKING
2. Peer- review
3. Debate among scientists
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Science benefits from debate among
researchers with different views
Scientists are often very critical
of each other’s ideas.
Important questions are
investigated by lots of
researchers in lots of different
ways.
Such debate should help
community of scientists answer
corrections correctly.
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Additional thoughts from your instructor…
How to be a mediocre scientist
• Study the same thing as
everyone else
• Show that popular
hypotheses are correct.
How to be a famous scientist
• Ask new questions
• Show popular hypotheses
wrong
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Instructor’s opinion: Any scientist who showed
humans not warming planet would be famous
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Study guide
1. Be able to analyze a scientific argument and identify the question,
hypothesis, test, and prediction.
2. Be able to apply the scientific method to design tests to answer
questions.
3. Be able to describe the steps in the peer review process.
4. Be able to summarize the difference between a scientific paper and a
typical magazine article.
5. Be able to identify the difference between a scientific question and a
non-scientific question.
6. Be able to use the “Baloney” detection kit to evaluate how strong a
scientific claim. (Be ready to evaluate a newspaper article describing
some scientific discovery.)
Reading:
All of chapter 1, especially the section on “The Nature of science”.
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Compare and/or contrast the terminology used by
Feynman below with the terms used to describe the
components of the scientific method used in class.
How to do science:
“First you guess. Don't laugh, this is the
most important step. Then you compute
the consequences. Compare the
consequences to experience. If it
disagrees with experience, the guess is
wrong. In that simple statement is the key
to science. It doesn't matter how beautiful
your guess is or how smart you are or
what your name is. If it disagrees with
experience, it's wrong. That's all there is
to it.”
-Richard Feynman, Nobel prize winning quantum physicist
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Sample exam questions
Describe three key differences between articles in popular
magazines and articles in scientific journals. You can make a list
if you want to.
Your instructor has just submitted a paper to the Journal of
North American Fisheries Management describing genetic
differences between cutthroat trout populations in Montana.
What process must the paper undergo to be published?
Describe the steps the editor of the journal uses to decide
whether to publish the paper. What is the name of this decision
process?
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Sample exam question
There are many populations of elk in Southwest
Montana, some of which live in areas with wolves and
some that live in areas without wolves. In the preceding
graph, we saw that the population in Northern
Yellowstone declined soon after wolves were released in
Yellowstone. Montana Fish Wildlife and Parks conducts
annual population counts of elk in many places in
Montana. How could you use this data to test the
hypothesis that wolves were responsible for the
population decline in Yellowstone?
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The End