1. Exploring Life: Scientific Methodology
Chapter 1
Exploring Life: Scientific Methodology

2. Nature of Biological Inquiry: Science as a PROCESS
Biological study is an ongoing process
Information is continually being built upon and modified
Science tries not to hold onto ideas just because they are familiar or comfortable
Try to judge the evidence objectively. Tries to avoid personal bias. (examples…)
Only when scientists are open to new ideas does scientific understanding increase

3. Concept 1.5: Biologists use various forms of inquiry to explore life
At the heart of science is inquiry
A search for information and explanation, often focusing on specific questions about the natural world in us and around us
Biology blends two main processes of scientific inquiry
Discovery science
Hypothesis-based science

4. Discovery science (“observational” research)
Describes natural structures and processes as accurately as possible through careful observation and analysis of data

5. Types of Data Data Are recorded observations
Can be quantitative or qualitative
Figure 1.24

6. Using the Scientific Method to solve a problem

7. The Myth of the Scientific Method
Is an idealized process of inquiry
Very few scientific inquiries strictly adhere to the “textbook” scientific method, but follow the same basic sequence
The general idea 

8. Hypothesis-based science
In science, inquiry that asks specific questions usually involves the proposing and testing of hypotheses
In science, a hypothesis
Is a tentative answer to a well-framed question, an explanation on trial
Makes predictions that can be tested
A scientific hypothesis must have two important qualities
It must be testable
It must be falsifiable

9. We all use hypotheses in solving everyday problems
Observations
Questions
Hypothesis # 1: Dead batteries
Hypothesis # 2: Burnt-out bulb
Prediction:
Replacing batteries
will fix problem
Replacing bulb
Test prediction
Test does not falsify hypothesis
Test falsifies hypothesis
Figure 1.25

10. Deduction: The “If…then” Logic of Hypothesis-Based Science
In deductive reasoning
The logic flows from the general to the specific; If A = B and B = C, then A = C
Ex: Red meat has iron in it and beef is red meat, so beef has iron in it.
If a hypothesis is correct, then we can expect a particular outcome
prediction: is a forecast, based on your hypothesis.
Experiment to see if your prediction came true.
If not, your hypothesis must be rejected. If the predictions do come true, your hypothesis MAY be correct (accepted).

11. Designing controlled experiments
Experiment must be designed to:
Test the hypothesis
Test the effect of one variable by comparing control groups and experimental groups in a way that cancels the effects of unwanted variables
variables, constants/controls, # of trials, replicates, repeatability, reliability, accuracy, sampling

12. A controlled study: Variables:
Experimental variable is the variable that is purposely changed or manipulated.
All other variables need to remain constant, or “controlled”. Ensures that the phenomena observed result from factors we think they do.
Groups:
Test group (or “experimental”group) is a group of subjects that are exposed to the experimental variable.
Control group is a group for comparison that is not exposed to the experimental variable; ex: a placebo may be used to simulate medication.

13. Science, Technology, and Society
Technology applies scientific knowledge for some specific purpose
“Bioinformatics":  analysis of biological information using computers and statistical techniques
Modeling (ex: pharmacology/drug design, ecological models)
Data collection and analysis (ex: DNA sequencing = Human Genome Project - mapping of 20-25,000 genes, over 3.3 billion base pairs) 

14. What should you look for when you read about science?
Be Critical when reading a scientific study
What should you look for when you read about science?
Beware of anecdotal data
This is when people use their intuition or personal experiences as data.
Understand methodology and results
Does the data justify the conclusions inferred by the scientists?
Be able to read a graph
Have some understanding of statistics

15. Nature of Biological Inquiry
Experiments generate data that’s ideally quantitative and objective
Data is usually tabulated in tables or displayed in graphs
. . . a Line graph.
Line graphs are used to track changes over short and long periods of time, ex: rate of change. When smaller changes exist, line graphs are better to use than bar graphs. Line graphs can also be used to compare changes over the same period of time for more than one group.
. . . a Bar Graph.
Bar graphs are used to compare things between different groups or to track changes over time. However, when trying to measure change over time, bar graphs are best when the changes are larger.
. . . a Pie Chart.
Pie charts are best to use when you are trying to compare parts of a whole. They do not show changes over time.

16. Reading a Graph What information does this line graph convey?
1.4 Making sense of a scientific study
Reading a Graph What information does this line graph convey?
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130
standard error
120
Diameter of trees (cm) 1 10
100
Site 1
Site 2
Site 3
Site 4

17. Human population
The Keeling Curve is a graph which plots the ongoing change in concentration of carbon dioxide in Earth's atmosphere since It is based on continuous measurements taken at the Mauna Loa Observatory in Hawaii that began under the supervision of Charles David Keeling.
Ice core data from G. Marland, T.A. Boden, and R.J. Andres

18. Observe, Collect, and Record Data
independent variable? 
dependent variable?

19. Nature of Biological Inquiry
Data analyzed using rigorous statistical analyses
Mathematical test: How valid is experimental data?
A significance level of 0.30 means that a conclusion has a 30% chance of being incorrect
Scientists would find this an unacceptably large chance of error
In general scientists will not say that they have a “significant” result unless the chances that their explanation is wrong are less than 5% (p < 0.05)

20. Nature of Biological Inquiry
Collected and analyzed data will then be interpreted to draw a set of conclusions
Conclusions may lead to development of new hypotheses and a new set of experiments
Other scientists may repeat study
Do their results gel with yours?
If not, yet more experiments may be needed to find out why not!

21. Science is a social activity
The Culture of Science
Science is a social activity
Characterized by both cooperation and competition
Importance of PEER REVIEW
Findings should be accurately written up and published where it can be subject to “peer review”
Must include methods, data, conclusions; should be repeatable
Others can learn from it, build on it.
Other scientists judge quality of the work
Figure 1.31

22. Reading about scientific information
Scientific journals are considered the best primary source of information but can be difficult for the lay person to understand.
Peer reviewed
Ex: American Journal of Botany, Journal of Zoology, etc
List of Biological journals
Often the lay person reads secondary sources and must be wary of information taken out of context.
Be careful of information on the Internet by using reliable sources such as URLs with .edu, .gov and .org
Public Library of Science

23. How the Cause of Ulcers Was Discovered: The scientific method in action
Observations: many patients had a particular bacterium near their ulcers
Hypothesis: Helicobacter pylori is the cause of gastritis and ulcers.(1982 by Dr. Barry Marshall and Dr. Robin Warren )
Experiment/observations:
1st – H. pylori was isolated and grown from ulcer patients
2nd – humans swallowing a H. pylori solution resulted in inflammation in their stomachs
Conclusion: H. pylori was the cause of most ulcers and can be cured by antibiotics
See:

24. A controlled study in action
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1.3 Science is a process a.
State Hypothesis:
Antibiotic B is a better treatment for
ulcers than antibiotic
Large number of subjects were selected
Subjects were
divided into three groups b.
Perform Experiment:
Groups were treated the same
except as noted
Control group:
received
placebo
Test group 1:
received
antibiotic A
Test group 2:
received
antibiotic B c.
Collect Data:
Each subject was examined
for the presence of ulcers d.
100 80 80 60 60
Conclusion:
Hypothesis is
supported:
Antibiotic B is
a better
treatment for
ulcers than
antibiotic A
Effectiveness of Treatment (%) 40 20 10
Control
Group
Test
Group 1
Test
Group 2
a: © blickwinkel/Alamy; d: © Phanie/Photo Researchers, Inc.

25. Theories in Science
A scientific theory is a well-substantiated explanation of some aspect of the natural world that is acquired through the scientific method, and repeatedly confirmed through observation and experimentation.
From the US National Academy of Sciences: “The formal scientific definition of theory is quite different from the everyday meaning of the word. It refers to a comprehensive explanation of some aspect of nature that is supported by a vast body of evidence.
Many scientific theories are so well established that no new evidence is likely to alter them substantially. For example, no new evidence will demonstrate that the Earth does not orbit around the sun (heliocentric theory), or that living things are not made of cells (cell theory), that matter is not composed of atoms (atomic theory), or that the surface of the Earth is not divided into solid plates that have moved over geological timescales (the theory of plate tectonics)
One of the most useful properties of scientific theories is that they can be used to make predictions about natural events or phenomena that have not yet been observed.[7]”