The Scientific Process, The Cell Theory
January 15, 2003

Readings: Starr pps. 12-16, CD: 1.5-1.6

"Science is built up with facts, as a house is with stones. But a collection of facts is no more a science than a heap of stones is a house". --Jules-Henri Poincaré

"If we knew what we were doing, it wouldn't be called research, would it?" --Albert Einstein

I. How is Biology studied?

Biology

Questions

Scientific Method.

Science Process Skills:

1. Observing:
2. Questioning:
3. Inferring:

prediction

4. Measuring:

 

5. Communicating:

(A final Science Process Skill: Classifying

II. Experimentation: The Key to the Scientific Method

Control group: .

Experimental group:

Experiment: Why are we sleepy in N100?

Worksheet: Scientific Method

The "Science Cycle":

III. About the words "hypothesis", "theory", and "law":

1. A hypothesis

2. A theory is

Some examples of theories that have been rejected because they are now better explained by current knowledge:

Some examples of theories or phenomena that were initially rejected because they fell outside of the accepted knowledge of the time, but are well-accepted today due to increased knowledge and data include:

• The sun-centered solar system (Copernicus, 1500s)
• Warm-bloodedness in dinosaurs (on and off since the 1800s)
• The Germ-Theory of Disease (Louis Pasteur and Robert Koch, 1870s)
• Continental Drift (Alfred Wegener, 1920s)
• Transposons or "jumping genes" (Barbara McClintock, 1940s)
• The Endosymbiotic Theory (Lynn Margulis, 1960s)
• The Catastrophic Collison Theory (formation of the moon 4.5 B years ago)
• Helicobacter pylorii infections as the causitive agent of stomach ulcers (Robin Warren and Barry Marshall, 1982)

Note: The popular usage of the word theory differs fron the scientific use of the word theory!

3. Laws (ie: Newton's Law of Gravity)

Note: Hypothesis do not 'become' theories and theories do not 'become' laws (like, for example, a bill becomes a law in congress.) Each one is a different feature of the scientific method.

IV. A Big Theory of Biology: The Cell Theory

The discovery of the cell was made possible by the invention of the microscope

Robert Hooke, 1662:

Anton van Leewenhook, 1673:

Matthias Schleiden and Theodor Schwann,

 

The 3 parts of the Cell Theory

1.

2.

3.

Each one of these three tenets of the Cell Theory:

Objectives, 01 /15/ 03

1. Know the 'steps' of the scientific method and the science process skills
2. Explain the need for a control group whenever experiments are performed
3. Explain the use of the word 'theory' in the scientific process
4. Explain the 3 tenets of the Cell Theory, and the names of the scientists involved.

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