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Biology. The Dynamics of Life. Biology. “The Study of Life”. Characteristics of “LIFE”. Organization Reproduction Growth & Development Respond to its environment Stimulus Response
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Biology The 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.)
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. Qualitative observations DESCRIBE = descriptions such as color, odor, sound, and texture (using the senses). 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. Accident #1 Accident #2 Accident #3 Observations
The Scientific MethodOVERVIEW • Identify a PROBLEM to solve. • Make a HYPOTHESIS. • TEST the hypothesis and COLLECTDATA. (a controlled experiment) • PUBLISH the results. • Draw a CONCLUSION and [perhaps] develop a THEORY.
1. OBSERVATION leads to identifying a problemto 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 • Identify a PROBLEM to solve. • Make a HYPOTHESIS. • TEST the hypothesis and COLLECTDATA. (a controlled experiment) • PUBLISH the results. • Draw a CONCLUSION and [perhaps] develop a THEORY.
Parts of a Controlled Experiment • Control – the STANDARD against which the results of the experiment are COMPARED. • INDEPENDENT Variable (I.V.) – the condition that is tested because it affects the outcome of the experiment. • DEPENDENT Variable (D.V.) – the condition in an experiment that results from the changes made to the independent variable. • CONSTANTS – the conditions that remainthesame 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.