Chapter 1 Biology in the 21 Century Section 1-3 Scientific Thinking and Processes Be Able To Identify the different elements of scientific inquiry Explain the difference between theories and hypotheses Key Terms Key Terms: observation, data, hypothesis, experiment, independent variable, dependent variable, constant, theory.

Biology is a Science of Inquiry Observation Observation is the act of noting or perceiving objects or events using the senses. Observations can be recorded as data, quantitative or qualitative. In the 1990’s California biologist John Harte noted declines in Tiger salamander populations.

Forming and Testing Hypotheses hypothesisA hypothesis is proposed answer to a scientific question. predictionA prediction is the expected outcome when a hypothesis is tested. Statistics are used to mathematically determine if a hypothesis is correct. John Harte hypothesized that acidic snowmelt disrupted the development of salamander eggs in ponds. pH ?

Biologists Use Experiments to Test Hypotheses experimentAn experiment is a planned procedure to test a hypothesis. Biologists study the relationships between independent an dependent variables. An independent variable is a condition controlled in an experiment. The dependent variable is an observable change in the form of experimental data. John Harte measured salamander egg development at different pH levels. What is the role of constants?

Evaluating the Results of an Experiment

A Theory Explains a Wide Range of Observations theoryA theory is a set of related hypotheses that have been tested and confirmed to be true repeatedly. Theories can be changed based on new evidence. John Harte’s hypothesis later were accepted as theory upon further study by other biologists.