1. Chapter 1
Introduction to the Scientific Method Can Science Cure the Common Cold?

2. Biology 103 Three Websites Dr. Brent Palmer Syllabus Schedule
1. UK Blackboard
2. Class website  
3. Mastering Biology

3. WHY YOU SHOULD CARE ABOUT BIOLOGY
Biology is about you!
Cancer - 1 IN 4 people will get cancer
Lung Cancer
1/3 of U.S. smokes
160,000/yr get lung cancer
145,000 will die in 3 years (90%)
Skin cancer –
melanoma is the most deadly form of cancer!
Breast cancer
1 in 9 women will get

4. WHY YOU SHOULD CARE ABOUT BIOLOGY
Destruction of tropical rain forests
Hundreds of thousands of acres are cleared every day
1-2 percent every year
They will never grow back
Green house effect is here
Melting of glaciers and polar ice caps
Crop failures, drought, famine

5. WHY YOU SHOULD CARE ABOUT BIOLOGY
Loss of Biological diversity
100,000 species extinct in the next 20 yrs
nearly 1/4 of all species on earth
They are lost forever
genes are lost --> cure for cancer and AIDS gone
Aesthetics and moral --> a barren planet

6. WHY YOU SHOULD CARE ABOUT BIOLOGY
Overpopulation
I remember 3 billion people on the planet, then 4, then 5, then 6 billion people
Now 6,860,482,878 people in the world!
population will double in 40 years
10-14 billion people by 2050
mostly in poor 3rd world countries
can we continue to feed the world, especially with the green house effect?
balance of world power?

7. 1.1 The Process of Science
Science is NOT a giant collection of facts to be memorized.
Science is a Process, using the scientific method:
Observing
Proposing ideas - Hypotheses
Testing the hypotheses
Discarding those ideas that fail

8. 1.1 The Process of Science The Nature of Hypotheses
Hypothesis: proposed explanation for observation
Testable and potentially falsifiable
Were to hypotheses come from?

9. 1.1 The Process of Science The Nature of Hypotheses
Both logical and creative influences are used
Chance
Logic
Intuition
Experience
Previous scientific
results
Imagination
HYPOTHESIS
Scientific theory
OBSERVATION
QUESTION
Figure 1.1

10. 1.1 The Process of Science Science, Technology, and Education
Who is conducting ‘science’?
Who is using technology?
Who is has more education?

11. 1.1 The Process of Science Science versus Technology
Science is a process that uses the scientific method
It may not require technology, depending upon hypothesis
Technology uses advanced instrumentation
But just by having instrumentation does not mean it is being used to in science (i.e., not testing hypothesis).

12. 1.1 The Process of Science Science, Technology, and Education
Who is conducting ‘science’?
Who is using technology?
Who is has more education?

13. 1.1 The Process of Science Pseudoscience Pretends to be science
Often starts with a conclusion and then tries to find ‘proof’ for it
Only accepts evidence that supports their theory, and rejects evidence that does not support it

14. 1.1 The Process of Science Scientific Theory
Powerful, broad explanation of a large set of observations
Rests on many hypotheses that have been tested
Generates additional hypotheses

15. 1.1 The Process of Science Example: Germ Theory
People used to think diseases were caused by things like:
bad air – so they would not go out at night, or
bad blood – which they treated with blood letting
Louis Pasteur observed that microorganisms caused milk to spoil
Hypothesized the microorganisms caused deseases too
Robert Koch demonstrated that anthrax bacteria caused the disease in mice

16. 1.1 The Process of Science The Logic of Hypothesis Tests
Inductive reasoning: combining a series of specific observations into a generalization
Fruits and Veg’s contain lots of Vit C
People who eat lots of fruits and Veg’s are generally healthier
Vit C is an anti-inflammatory agent, which reduces nose & throat irritation
From these observations a hypothesis is formed:
Consuming vitamin C decreases the risk of catching a cold

17. 1.1 The Process of Science The Logic of Hypothesis Tests
Inductive reasoning
EXAMPLE
The sun rises in the east every morning
It travels across the sky
It sets in the west every morning
> Therefore, the sun rotates around the earth
Just because a series of observations appear right doesn’t mean they are.
> MUST BE TESTED!!

18. 1.1 The Process of Science The Logic of Hypothesis Tests
To test, make a prediction using deductive reasoning.
attempts to show that a conclusion necessarily follows from a set of premises
i.e. it predicts the outcome based of an action, test or investigation
Uses an “if…then” statement

19. (that is testable and fasifiable)
1.1 The Process of Science
The Logic of Hypothesis Tests
The process looks something like this:
Hypothesis
(that is testable and fasifiable)
Consuming vitamin C reduces
the risk of catching a cold.
Make prediction
If vitamin C decreases the risk
of catching a cold, then people
who take vitamin C
supplements will experience
fewer colds than people
who do not.
Test prediction
Conduct experiment or survey
to compare number of colds
in people who do and do not
take vitamin C supplements.
Figure 1.3

20. 1.1 The Process of Science Figure 1.3 (continued) If people who
take vitamin C
suffer fewer
colds than
those who do
not. . .
If people who
take vitamin C
suffer the
same number
of colds or
more than
those who do
not. . .
Conclude that
prediction is
true
Conclude that
prediction is
false
Do not reject
Reject the
the hypothesis
hypothesis
Conduct
additional
tests
Consider
alternative
hypotheses
Figure 1.3 (continued)

21. 1.1 The Process of Science The Logic of Hypothesis Tests
A hypothesis that fails our test is rejected and considered disproven.
A hypothesis that passes is supported, but not proven.
Why not? An alternative hypothesis might be the real explanation.
> it is possible to disprove a hypothesis, but never possible to prove a hypothesis

22. 1.2 Hypothesis Testing Vit C helps prevent colds
First proposed by Noble prize winning chemist Linus Pauling in 1970
Based on a few studies conducted between 1930s and 1970s
Subsequently disproven by lots of more thorough research

23. 1.2 Hypothesis Testing When is a hypothesis considered true?
When one hypothesis has not been disproven through repeated testing and
all reasonable alternative hypothesis have been eliminated.
But may be rejected in the future
>Truth in science is what we know an understand based on all currently available information, but may be changed when new information is available

24. 1.2 Hypothesis Testing
The most powerful way to test hypotheses: do experiments

25. 1.2 Hypothesis Testing
Experiments support the hypothesis that the common cold is caused by a virus.
(a) Cold–causing virus
(b) How the virus causes a cold
Nasal
passages
Host cell
Throat 1
Virus
Virus introduces its
genetic material into a
host cell.
Protein
shell
Genetic
material and
proteins 2
The viral genetic material instructs the
host cell to make new copies of the
virus. Immune system cells target
infected host cells. Side effects are
increased mucus production and throat
irritation.
Virus
copies 3
Immune
system cells
New copies of the virus are
released, killing host cell. These
copies can infect other cells in
the same person or cells in
another person (for example, if
transmitted by a sneeze).
Released
virus
copies
Mucus
Figure 1.4

26. 1.2 Hypothesis Testing The Experimental Method - Terminology
Experiments are carefully regulated situations.
Variables: factors that can change in value under different conditions
Independent variables can be manipulated by the scientist
Dependent variables change depending upon the dependent variable

27. 1.2 Hypothesis Testing Controlled Experiments
Controlled experiment: tests the effect of a single variable at a time
Control: a subject who is not exposed to the experimental treatment
Differences can be attributed to the experimental treatment.

28. 1.2 Hypothesis Testing
PLAY
Animation—Science as a Process: Arriving at Scientific Insights

29. 1.2 Hypothesis Testing Controlled Experiments
Example: Echinacea tea experiment:
Hypothesis: drinking Echinacea tea relieves cold symptoms
Experimental group drinks Echinacea tea 5-6 times daily.
Control group drinks “sham” Echinacea tea (placebo).
Both groups rated the effectiveness of their treatment on relieving cold symptoms.

30. 1.2 Hypothesis Testing Controlled Experiments
People who received echinacea tea felt that it was 33% more effective at reducing symptoms.
Figure 1.7

31. 1.2 Hypothesis Testing Minimizing Bias in Experimental Design
If human subjects know whether they have received the real treatment or a placebo, they may be biased.
Blind experiment: subjects don’t know what kind of treatment they have received
Double blind experiment: the person administering the treatments also doesn’t know until after the experiment is over
“gold standard” for experimentation

32. 1.2 Hypothesis Testing Using Correlation to Test Hypotheses
It is not always possible or ethical to experiment on humans.
Using existing data, is there a correlation between variables?

33. 1.2 Hypothesis Testing Using Correlation to Test Hypotheses
Hypothesis: stress makes people more susceptible to catching a cold
Is there a correlation between stress and the number of colds people have caught?

34. 1.2 Hypothesis Testing Using Correlation to Test Hypotheses
Results of such a study: the number of colds increases as stress levels increase.
Figure 1.10

35. 1.2 Hypothesis Testing Using Correlation to Test Hypotheses
Caution! Correlation does not imply causation.
The correlation might be due to other reasons.

36. 1.2 Hypothesis Testing Using Correlation to Test Hypotheses
Figure 1.11

37. 1.3 Understanding Statistics
Overview: What Statistical Tests Can Tell Us
Statistics extend the results from small samples to an entire population.
It determines if the difference between two samples are real or due to chance
Statistics measures:
Sample size
Variation with the sample

38. 1.3 Understanding Statistics
The Problem of Sampling Error
Sampling error: the effect of chance
We can calculate the probability that a result is simply due to sampling error.
Statistically significant: an observed difference is probably not due to sampling error

39. 1.3 Understanding Statistics
The Problem of Sampling Error
Experimental and control groups (samples) will never be identical because all living organisms are unique
Sometimes the observed difference between groups is only due to sample error and not experimental treatment

40. 1.3 Understanding Statistics
The Problem of Sampling Error
Effect of zinc lozenges on length of a cold
Did zinc really shorten colds?
Or did those people just get over the cold faster anyway?

41. 1.3 Understanding Statistics
The Problem of Sampling Error
Confidence interval: the range of values from a sample that has a 95% probability of containing the true population mean (average).
Large population variation = large confidence interval
Small population variation = small confidence interval
Standard Error = amount of variability in the sample

42. 1.3 Understanding Statistics
Confidence interval: the range of values from a sample that has a 95% probability of containing the true population mean (average).
Only Exp 1 is “Statistically Significant”

43. 1.3 Understanding Statistics
Factors that Influence Statistical Significance
Sample size
Bigger is better: more likely to detect differences
Variance of the population
Statistical significance is harder to find in highly variable populations

44. 1.3 Understanding Statistics
What Does Statistical Significance Really Mean?
Most scientists accept a 5% probability of error (i.e. P<0.05)
This means that the probability that the experimental groups were different by sampling error alone is 5%
That means that 1 in 20 (5%) of statistically significant research is really just a false positive

45. 1.3 Understanding Statistics
Factors that Influence Statistical Significance
Figure 1.15

46. 1.3 Understanding Statistics
What Statistical Tests Cannot Tell Us
If an experiment was designed and carried out properly
Evaluate the probability of sampling error, not observer error
May not be of any biological significance

47. 1.4 Evaluating Scientific Information
Primary Sources
Researchers can submit a paper about their results to a professional journal (primary source).
Peer review: evaluation of submitted papers by other experts
Secondary sources: books, news reports, the internet, and advertisements

48. 1.4 Evaluating Scientific Information

49. 1.4 Evaluating Scientific Information
Information from Anecdotes
Anecdotal evidence is based on one person’s experience, not on experimental data.
Example: a testimonial from a celebrity

50. 1.4 Evaluating Scientific Information
Science in the News
Secondary sources may be missing critical information or report the information incorrectly.
Consider the source of media reports.

51. 1.4 Evaluating Scientific Information
Science in the News
Be careful with the internet since anyone can post information.
Be very cautious about claims made in paid advertisements.

52. 1.4 Evaluating Scientific Information
Understanding Science from Secondary Sources
Use your understanding of the process of science to evaluate science stories.
News media generally highlight only those science stories that seem newsworthy.
They are more likely to report a positive result than a negative one.

53. 1.4 Evaluating Scientific Information
Checklist for evaluating science in the News
Table 1.2 on page 24.

54. 1.5 Is There a Cure for the Common Cold?
No effect on cold susceptibility:
Vitamin C
Exposure to cold temperatures
Exercise
No vaccine for the common cold
But prevention methods are known.
Wash your hands!