BIOLOGYThe Dynamics of Life

BIOLOGY“The Study of Life”

Characteristics of “LIFE”

Organization Reproduction Growth & Development Respond to its environment

Stimulus Response (Homeostasis – The ability to control its internal

environment. Adjustment of water & minerals in an organism to achieve balance.)

Observations

A scientist uses his senses of sight, touch, hearing, and smell to examine an object in detail. He may use instruments to extend these senses.

1. Qualitative observations DESCRIBE = descriptions such as color, odor, sound, and texture (using the senses).

2. Quantitative observations MEASURE = using an instrument of measurement to measure the amount or number.

Observations

A scientist improves his skills of observation and his communication skills by practice.

Observe the following and describe as much as you can.

1. Accident #12. Accident #23. Accident #3

The Scientific MethodOVERVIEW

1. Identify a PROBLEM to solve.2. Make a HYPOTHESIS.3. TEST the hypothesis and COLLECT

DATA. (a controlled experiment)4. PUBLISH the results.5. Draw a CONCLUSION and [perhaps]

develop a THEORY.

1. OBSERVATION leads to identifying a problem to solve. “Observing the world around you is the

foundation of scientific investigation.”

2. Making a HYPOTHESIS.

an EXPLANATION for a question or problem that can be formally TESTED.

Not a RANDOM GUESS.

3. Collecting DATA. (numbers)

Test the hypothesis in a controlled EXPERIMENT can be used to obtain data to test a HYPOTHESIS.

4. PUBLISH results

allows other scientists to repeat the experiment and VERIFY the results.

4. Forming a THEORY.

A THEORY is a hypothesis that is supported by a LARGE body of scientific evidence.

(not an unproven idea or hunch)

Also

6. Developing new HYPOTHESES. 7. Revising the THEORY.

The Scientific MethodREVIEW

1. Identify a PROBLEM to solve.2. Make a HYPOTHESIS.3. TEST the hypothesis and COLLECT

DATA. (a controlled experiment)4. PUBLISH the results.5. Draw a CONCLUSION and [perhaps]

develop a THEORY.

Parts of a Controlled Experiment

A. Control – the STANDARD against which the results of the experiment are COMPARED.

B. INDEPENDENT Variable (I.V.) – the condition that is tested because it affects the outcome of the experiment.

C. DEPENDENT Variable (D.V.) – the condition in an experiment that results from the changes made to the independent variable.

D. CONSTANTS – the conditions that remain the same in all of the experimental groups.

Francesco Redi’s Experiment

Observed – Maggots appeared on meat a few days after flies were present

Francesco Redi’s Experiment

Prediction – Flies produced maggots and keeping flies away from meat would prevent the appearance of maggots.

Francesco Redi’s Experiment

Hypothesis - IF the gauze covering keeps flies away from the meat, THEN no maggots will appear.

Francesco Redi’s Experiment

Independent variable - gauze covering that keeps flies away from meat.

Francesco Redi’s Experiment

Dependent variable - whether maggots appear on the meat.

Francesco Redi’s Experiment

Controlled variables - Jars, type of meat, location, temperature, time.

Francesco Redi’s Experiment

Data - showed that maggots appeared on the meat without gauze – but not on covered jars.

Francesco Redi’s Experiment

Conclusion - Maggots formed only when flies came into contact with the meat. Not spontaneous generation.