1. Reminder The website for the course is http://www.bio200.buffalo.edu
To watch the slides used in lecture:
Username: BIO200
Password: darwin
To listen to the lecture and see the slides:
Go to UB Learns. Check into Bio200 course.
Go to Classroom recordings

2. TopHat Questions
for Bio200 class

3. Clicker Question Have you used clickers before?
Yes No 30

4. What is your intended career?
1) Health related profession
2) Business
3) Engineering
4) Science
5) None of the above
6) I don’t know 30

5. Huh?
What is science?

6. an attempt to explain the natural world in terms of
Science is
an attempt to explain the natural world in terms of
natural processes.

7. No supernatural explanations are permitted.
Get it?
Natural.
No Supernatural Explanations

8. SCIENCE AS A WAY OF KNOWING “Science
SCIENCE AS A WAY OF KNOWING “Science .... Is the organized, systematic enterprise that gathers knowledge about the world and condenses the knowledge into testable laws and principles.” E.O. Wilson
Science is....
• a body of facts and principles about the physical world
• a method of discovery

9. The Classical “Scientific Method”
Ask a Question
Form an Hypothesis
Make Predictions
Test Predictions: Experiment; collect data
Draw a conclusion: compare your data to the hypothesis/prediction and draw a conclusion

10. What happens after Step 5?
On the basis of the data make conclusions about validity of the hypothesis.
DATA
HYPOTHESIS
HYPOTHESIS
REJECTED
SUPPORTED
New Tests & New Hypotheses
Science is self-correcting

11. Characteristics of Science
1. Claims are tested:
repeatable observations and experiments
2. Law of Parsimony — “OCCAM” S RAZOR
3. Measurements are used.
4. Consilience is applied.
Principles of many fields are used to see if they are consistent with a discovery
How can we apply
this method?

12. Characterization of DNA structure
An Example:
Characterization of DNA structure
Question: What is the structure of DNA?
DNA had been identified as possibly the genetic substance by Avery, Macleod and McCarty at the Rockefeller Institute in 1944, but its structure was unclear to anyone in 1950
DNA hypotheses: Crick and Watson hypothesized that DNA had a helical structure.

13. Conclusion: DNA’s structure is probably a helix
DNA prediction: From earlier work on tobacco mosaic virus, Watson was aware of the significance of the possibility of a helix, so he predicted this shape & if this were true then a X-ray picture would show it.
DNA experiment: Rosalind Franklin in another lab took an X-ray diffraction photo of DNA. Unknown to her, a colleague showed Watson the picture and he recognized it had a helical structure
Conclusion: DNA’s structure
is probably a helix

14. The Classical “Scientific Method”
(Hypothetico—Deductive Method)
Ask a Question
Form an Hypothesis
Make Predictions
Test Predictions: Experiment; collect data
Draw a Conclusion: compare your data to the hypothesis/prediction and draw a conclusion

15. Types of Reasoning Applying a set of general logic rules
Deductive Reasoning
General  Specific
Applying a set of general logic rules
to a particular problem
******
Inductive Reasoning
Specific----- General
Generalizing on the basis of some observations

16. Notice the use of deductive reasoning:
DNA hypotheses: Crick and Watson hypothesized that DNA was helical.
Reasoning from general principles of chemistry and what was known about helical structure of proteins, they guessed a similar structure might be found in DNA.
General principles  to a specific case
So Watson & Crick predicted a helix based on deductive reasoning

17. Notice the use of inductive reasoning:
DNA experiment: Rosalind Franklin in another lab took an X-ray diffraction photo of DNA. Unknown to her, a colleague showed Watson the picture and he recognized it was a helical structure
Conclusion: DNA’s structure
is probably a helix
Specific Case General Principles
So Watson & Crick generalized that DNA had a helical structure based on inductive reasoning

18. 2. Consistent with known facts 3. Probable
Characteristics of a Good Hypothesis
1. Simple
2. Consistent with known facts
3. Probable
4. Uses physical explanations
5. Stimulates research
6. Makes predictions
7. Testable

19. I have a fire-breathing dragon in my basement. Do you believe me?
Yes No
I don’t know 20

20. HOW DO WE DEAL WITH THIS KIND OF STATEMENT?
This is an extraordinary claim.
Extraordinary claims require extraordinary proof.
What kind of proof would we want?
Can we deal with this claim scientifically?

21. The Hypothetico-Deductive Method in action:
Question: Is there a fire-breathing dragon in the basement?
Hypothesis: There is a fire-breathing dragon in the basement
Prediction: ?
Test: ?

22. Suppose I counter every physical test you propose
with a special explanation of why it won't work.
Then what?
What's the difference between
an invisible, incorporeal, floating dragon
who spits heatless fire and no dragon at all?
What should we conclude?
***

23. What is the major problem with the dragon in the basement hypothesis?
Not simple
No predictions are possible
Doesn’t stimulate research
Not consistent with the known facts
Not testable 20

24. When do we accept an hypothesis?
1. When all attempts to falsify it
(i.e. show it false) have failed.
It is critical to repeat experiments!
2. When it is accepted
by the scientific community as
“true, beyond all reasonable doubt.”

25. From Hypothesis to Theory
HYPOTHESIS THEORY (Guess) (Major Conceptual Framework)
Speculative Certain
Simple Elaborate
Little Explanatory Power Great Explanatory Power

26. People should have 2 children per family
Clicker Question WHICH OF THE FOLLOWING STATEMENTS IS A SCIENTIFIC THEORY?
A camel is a mammal.
People should have 2 children per family
If the world’s population grows beyond 10 billion, then a massive natural die-off will occur.
The cell is the basic unit of living organisms and is composed of the same basic subunits wherever it occurs. All living cells are derived from previous cells.
Ozone molecules in the earth’s atmosphere are being broken apart by CFCs (chlorofluorocarbons). 30

27. WHICH OF THE FOLLOWING STATEMENTS IS A SCIENTIFIC THEORY?
1. A camel is a mammal. (FACT)
2. People should have 2 children per family. (OPINION)
3.If the world’s population grows beyond 10 billion, then a massive natural die-off will occur. (PREDICTION)
4. The cell is the basic unit of living organisms and is generally composed of the same basic subunits wherever it occurs. All living cells are derived from previous cells. (CELL THEORY)
5. Ozone molecules in the earth’s atmosphere are being broken apart by CFCs (chlorofluorocarbons). (FACT)

28. Asteroid/Comet Hypothesis of Dinosaur Extinction
Let’s Look at the
Asteroid/Comet Hypothesis of Dinosaur Extinction
1. Simple ?
2. Consistent with known facts ?
3. Probable ?
4. Uses physical explanations ?
5. Stimulates research ?
6. Makes predictions ?
7. Testable ?

29. Was Alvarez doing science?
How do you know?
Highlight all words and phrases that suggests that Alvarez was doing science.

30. The Classical “Scientific Method”
Is this an adequate description of the fate of the Asteroid/Comet hypothesis?
Ask a Question
Form an Hypothesis
Make Predictions
Test Predictions: Experiment; collect data
Draw a conclusion

31. Where on this diagram do we find the various events of the Alvarez journey?

32. explanation of what goes on.
The Simple form
of science in action
Is powerful.
But not an adequate
explanation of what goes on.

33. Outline the steps in sequence of the Alvarez journey.

34. The Simple Hypothetico-Deductive Method in Action
If this
Then hypothesis is supported!

35. If this
Then hypothesis is supported!

36. If this
Then Hypothesis is falsified! (Rejected)

37. THE HYPOTHESIS IS SUPPORTED
DATA FOR Typical BIO 200 CLASS
THE HYPOTHESIS IS SUPPORTED

38. Data from 2016

39. NEW QUESTION

40. NEW QUESTION

41. AND
THE
DATA
PLEASE

43. Conclusion?
Hypothesis is
supported

44. Come to Class Even if you’ve Gotta Crawl !
SO????
Come to Class
Even if you’ve
Gotta Crawl !