YOUR FINAL GRADE
A > 80 A- 79-80
B+ 78-79
B
70-78
theory
1
WHAT IS SCIENCE?
•  A systematic (logical, reasonbased) study of the physical or
material world.
theory
2
WHAT IS RELIGION?
Studies of material and non-material
world issues that are built upon
faith or intuition.
theory
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theory
4
DOES IT ?
… eliminates all
your backyard
mosquito
problems, blah,
blah, blah…
theory
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THIS IS WHAT I SAW !
theory
6
TWO OBSERVATIONS:
•  Patterns on wings
•  Side-to-side movements
theory
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FLIES THAT LOOK LIKE
SPIDERS?
theory
8
FOUR KINDS OF QUESTIONS:
•  Function (why or ultimate)
•  Mechanism (how or proximate)
•  Lineage (inheritance)
•  Ontogeny (development)
theory
9
TWO SPIDER FACTS:
•  Spiders are dangerous
•  Jumping spiders are territorial
theory
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WHAT IS A THEORY?
•  A coherent system of general
propositions.
theory
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MY NEW THEORY
CONSISTS OF:
•  Some facts - e.g.spiders are aggressive
•  Some assumptions - e.g. spiders
perceive flies as spiders, recognition is
visual •  Conditionals - e.g. if fact a and b are
true ….
theory
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HOW TO DEVELOP
THEORIES
•  Deduction - work from first principles
without experience influencing the
deductive process
•  Induction - accumulation of facts
leads to emergence of generalization
theory
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A GOOD HYPOTHESIS
SHOULD:
•  Be consistent with observations
made to date
•  Be one whose validity can be
tested by experiment
theory
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MY FORMAL HYPOTHESIS:
•  Picture winged flies are less likely
to be attacked by spiders than nonpicture winged flies
theory
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TWO HYPOTHESES:
•  HA - Differential attack on plain vs.
picture winged flies
•  H0 - Equal attack rates
theory
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EXPERIMENT 1
•  Release spiders into cages that
contain equal numbers of picturewinged and plain-winged (house
flies) flies
•  Count how many of each type of
fly are still alive 6 hours later
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RESULT
•  Many more picture-winged flies
than house flies alive after six
hours with spiders
theory
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SAMPLE TWO POPULATIONS
f
A
Body Size
B
19
ON LUCK ALONE
f
A
A
B
A
A
A
A
A
Body Size
B
BB
B
B
B
B
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OR
f
A
B
Body Size
21
ERRORS:
•  TYPE I - Conclude that there is an
effect when there isn’t
•  TYPE II - Conclude that there is no
effect when there is
theory
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OTHER EXPLANATIONS:
•  Differences in encounter rates
•  Differences in odor
•  Differences in escape ability
•  Differences in defense
theory
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EXPERIMENT 2
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RESULT
•  Picture winged flies are attacked less
often than house flies
theory
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THE PERFECT CONTROL IS:
•  A picture-winged fly without the
picture!
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RESULT
•  Picture-winged flies without their
stripes are attacked much more often
than control flies (with their stripes
intact)
•  Houseflies with picture wings are
attacked at an intermediate rate suggests that body movement is also
important
theory
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WHAT THESE
EXPERIMENTS DO:
•  They support our theory of fly
protection via mimicry of spiders
BUT
•  They cannot prove that our theory is
correct
theory
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WHAT IF YOUR THEORY IS
UNACCEPTABLE?
BACK TO THE DRAWING BOARD:
•  Check underlying assumptions
•  Re-examine theory structure
•  Re-examine experiments
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AN EXAMPLE – THE OUT
OF AFRICA THEORY
•  Homo sapiens arose in Africa and
migrated to other parts of the world to
replace other hominid species,
including Homo neanderthalensis
without interbreeding
(i.e. driven to extinction
and
not assimilation)
theory
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AN EXAMPLE – THE OUT
OF AFRICA THEORY: II
•  DNA evidence supports the idea that a
small group of humans left Africa and
populated the world
•  However, the data show that modern
humans harbour Neanderthal genes (ca.
1-4%)
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1/4/12
Deadly European virus found in B.C. salmon - British Columbia - CBC News
updated
Deadly European virus found in B.C.
salmon
CBC News
Posted: Oct 17, 2011 2:19 PM PT
Last Updated: Oct 17, 2011 2:24 PM PT
92
A highly infectious virus found in wild salmon on B.C.'s central coast could have a devastating impact on
the province's wild salmon and herring, according to some experts.
Simon Fraser University Prof. Rick Routledge discovered the disease known as infectious salmon anemia,
or ISA, in two of 48 sockeye smolts collected. The fish were caught 100 kilometres from the nearest fish
farm, and had never been out to sea.
The infection was diagnosed by Dr. Fred Kibenge, an employee at the Atlantic Veterinary College in
P.E.I., who notified the CFIA.
Routledge, who's doing a long-term study on the collapse of Rivers Inlet sockeye, says the exotic disease
could have a devastating impact on wild salmon in B.C.
theory
He says the possible impact of the virus can't be taken
lightly
and there must be an immediate response32to
assess the extent of the outbreak.
"First thing that I think we should do is start looking for the source," said Routledge.
1/4/12
B.C. salmon virus tests find no infectious anemia - British Columbia - CBC News
B.C. salmon virus tests find no infectious
anemia
The Canadian Press
Posted: Nov 8, 2011 5:16 PM PT
Last Updated: Nov 8, 2011 2:28 PM PT
34
Tests on 48 wild salmon samples have found no cases of infectious salmon anemia in B.C., a Canadian
Food Inspection Agency official says.
The tests the Fisheries Department did were verified by an independent lab in Norway, said Con Kiley,
director of the agency's national aquatic animal health program.
The samples were tested after a laboratory at the University of Prince Edward Island suspected the highly
infectious salmon anemia in juvenile sockeye from Rivers Inlet on B.C.'s central coast.
theory
33
Paul Kitching, the chief veterinary officer for B.C., said anyone who says the virus is present in the
province based on the PEI results involving such a small sample size is misrepresenting the science.
"I can also say that as editor-in-chief of an international veterinary journal, this would be considered poor
1/4/12
New version of salmon virus may have started in B.C., expert says | The Vancouver Observer
New version of salmon virus may have started in B.C., expert says
Federal scientist says a possible new strain of a potentially deadly
virus previously found only in foreign Atlantic-salmon fish farms has
been discovered in Pacific salmon.
Will Campbell Posted: Dec 15th, 2011
Read More: Politics Are Nylund Department of Fisheries and Oceans farmed
salmon fish farming head molecular geneticist Kristi Miller Nanaimo sockeye
salmon University of Bergen
What may be a new variant of a potentially lethal virus that has decimated
fish farms in eastern Canada, Chile and Europe has been found in B.C. wild
salmon, an inquiry was told Thursday.
A federal scientist told the Cohen Commission infectious salmon anemia
virus was found in B.C. sockeye and pink salmon tested at a Department of
Fisheries and Oceans lab in Nanaimo.
theory
Cohen Commission: witnesses to testify on salmon 'diseases' and
aquaculture
That finding echoes a controversial October report by SFU researchers that
34
HOW WE DO SCIENCE
OBSERVATION
SEARCH FOR EXPLANATION
DEVELOP THEORY
DERIVE TESTABLE HYPOTHESES
CONDUCT EXPERIMENTS
CONDITIONALLY ACCEPT, REJECT OR
REVISE THEORY
MORE
EXPERIMENTS
theory
35
WHAT IS A PARADIGM?
•  A conceptual system much broader in
scope than a theory and one which is
associated with a recognized scientific
achievement(s)
theory
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WHAT IS A LAW?
•  A fundamental generalization
about some relationship that is
invariant under the same
conditions.
theory
37
HOW WE DO SCIENCE
OBSERVATION
SEARCH FOR EXPLANATION
DEVELOP THEORY
DERIVE TESTABLE HYPOTHESES
CONDUCT EXPERIMENTS
CONDITIONALLY ACCEPT, REJECT OR
REVISE THEORY
MORE
EXPERIMENTS
theory
38