Chapter 1: The Science of Biology Section 1: What is Science? CCS Biology Mr. Bogusch Bill Nye - Science

What Science Is and Is Not Science as a Way of Knowing oScience is an organized way of gathering and analyzing evidence about the natural world oScience is a process oScience only deals with the natural world oScience collect and organize information in an orderly way oScience explanations are based on evidence, not belief

The Goals of Science One goal of science is to provide natural explanations for events in the natural world. –Science uses these explanations to understand patterns in nature to make useful predictions

Science, Change, and Uncertainty oScience is always changing; it never stands still oUncertainty is part of what makes science exciting

Scientific Method 1. Observing and Asking Questions Observation – the act of noting and describing events or processes in a careful, orderly way Philosopher Arthur Schopenhauer: “think something that nobody has thought yet, while looking at something that everybody sees.”

For example, researchers observed that marsh grass grows taller in some places than others. This observation led to a question: Why do marsh grasses grow to different heights in different places?

Scientific Method 2. Inferring and Forming a Hypothesis oInference- logical interpretation based on what scientists already know oHypothesis – scientific explanation for a set of observations that can be tested in ways that support or reject it.

Inference can lead to a hypothesis, or a scientific explanation for a set of observations that can be tested in ways that support or reject it. What inference scan you make about the marsh grasses?

–For example, researchers inferred that something limits grass growth in some places. Based on their knowledge of salt marshes, they hypothesized that marsh grass growth is limited by available nitrogen.

Scientific Method 3. Designing Controlled Experiments oControlled experiment – testing a hypothesis with only one variable is changed oVariable – factors that can change –For example: light, time, availability of nutrients oControlling variables oIndependent variable – (manipulated variable) the variable that is changed oDependent variable – the variable that changes in response to the independent variable –The variable you measure

–For example, the researchers selected similar plots of marsh grass. All plots had similar plant density, soil type, input of freshwater, and height above average tide level. The plots were divided into control and experimental groups. –The researchers added nitrogen fertilizer (the independent variable) to the experimental plots. They then observed the growth of marsh grass (the dependent variable) in both experimental and control plots.

Scientific Method oControl Group – receives no experimental treatment Experiment Group – receives experimental treatment; one independent variable is changed in

–Scientists record experimental observations, gathering information called data. There are two main types of data: quantitative data and qualitative data.

Scientific Method 4. Collecting and Analyzing Data oData – information from detailed experimental records oQuantitative Data – numbers obtained by counting or measuring –Ex. Number of plants per pot, plant height, plant width oQualitative Data – descriptive observations that usually cannot be counted –Ex. Plant growing sideways or upright –Sources of Error – researchers must be careful to avoid errors in collecting data

–This graph shows how grass height changed over time.

Scientific Method 5. Drawing Conclusions oScientists use experimental data as evidence to support, refute, or revise the hypothesis being tested, and to draw a valid conclusion. oWhen Experiments are not possible oIt is not always possible to test a hypothesis with an experiment oAnimal behavior in the wild oEthical concerns (especially with humans)

Scientific Method Song