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Chapter 2: The Science of Biology
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Scientific inquiry: Making observations in nature, asking questions about these observations, and actively seeking answers to those questions
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Data: recorded observations
Quantitative data: observations recorded as measurements—always involve a number Qualitative data: descriptive data (color, sound, shape, texture etc.) – used when numerical data is impossible or difficult to obtain Inference: logical conclusion based on an observation; ex. if doorbell rings, then someone is at the door
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Variables Variable: condition that can vary in an experiment
Independent variable: the factor that is changed or controlled by the experimenter when testing a hypothesis Dependent variable: the factor that is changed as a result of the changes made in the independent variable
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Scientific Method Procedures used by biologists and other scientists to gather information used in problem solving and experimentation
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Scientific Method
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Observation Use of the senses to gather and record information about structures or processes
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Asking a Question Based on observations; one or more questions are generated
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Hypothesizing Hypothesis: a suggested answer to a well-defined scientific question; an educated guess Always written as an “if…then…” statement
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Predicting To test hypothesis it is necessary to make predictions that logically follows from the hypothesis A statement made in advance that states the results that will be obtained from testing the hypothesis
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Test Testing a hypothesis or prediction by gathering data under controlled conditions Controlled experiment: experiment that tests the effect of a single variable it will not be influenced by the variable the other groups are testing
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Organizing Data Involves placing observations and measurement (data) in order charts, tables, or maps
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Analyzing Data Collected and organized data must be analyzed
Graphs are frequently used to display data Three types of graphs may be used: Line graphs Bar graphs Pie graphs
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Bar Graphs X-axis: independent variable Y-axis: dependent variable
Used to display numerical data that is obtained by counting
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Line Graphs X-axis: independent variable Y-axis: dependent variable
Most useful for showing trends or continuous change
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PIE GRAPHS Uses circle divided into sections to display data
Each section represents a part of the whole All sections placed together equal 100% of the whole
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Forming a Theory A broad and comprehensive statement of what is thought to be true Supported by considerable evidence Ties together related hypotheses
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Terms Evidence: collected body of data from observations and experiments Model: physical, mathematical, or mental representations of how people understand a process or idea Technology: application of scientific understanding for some specific purpose
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1. What should you do if your test does not support your hypothesis?
Revise the hypothesis or pose and test a new one.
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2. How is a prediction different from a hypothesis?
A hypothesis is a possible answer to a scientific question, while a prediction is a statement about what will happen under a specific set of conditions. Multiple predictions can be based on a single hypothesis.
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Independent variables answer the question "What do I change?".
Dependent variables answer the question "What do I observe?". Controlled variables answer the question "What do I keep the same?".
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