Chapter 2: The Science of Biology

Scientific inquiry: Making observations in nature, asking questions about these observations, and actively seeking answers to those questions

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

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

Scientific Method Procedures used by biologists and other scientists to gather information used in problem solving and experimentation

Scientific Method

Observation Use of the senses to gather and record information about structures or processes

Asking a Question Based on observations; one or more questions are generated

Hypothesizing Hypothesis: a suggested answer to a well-defined scientific question; an educated guess Always written as an “if…then…” statement

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

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

Organizing Data Involves placing observations and measurement (data) in order charts, tables, or maps

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

Bar Graphs X-axis: independent variable Y-axis: dependent variable Used to display numerical data that is obtained by counting

Line Graphs X-axis: independent variable Y-axis: dependent variable Most useful for showing trends or continuous change

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

Forming a Theory A broad and comprehensive statement of what is thought to be true Supported by considerable evidence Ties together related hypotheses

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

1. What should you do if your test does not support your hypothesis? Revise the hypothesis or pose and test a new one.

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.

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?".