biology ppt
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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.