Biology Notes Chapter 1 Scientific Method

Science is an organized way of using evidence to learn about the natural world.

The goal of science is to investigate and understand the natural world, to explain events in the natural world, and to use those explanations to make predictions.

Scientific thinking begins with observations – The process of gathering information about events using the senses (usually sight or hearing).

This information is called data. (datum)

Quantitative data are expressed using numbers obtained by measuring or counting.

Qualitative data are descriptive and involve characteristics that can’t usually be counted.

Scientists use data to make inferences, or logical interpretations based on prior knowledge or experience.

Inferences are conclusions or deductions… and should not be confused with opinions.

Opinions are beliefs or judgments of the mind that should be left out when collecting data.

A theory develops when an hypothesis is tested or supported many times.

Theories are well-tested observations that unify a broad range of observations.

…they are not “the truth” and can be revised or replaced as new evidence is uncovered.

How Scientists Work: The Scientific Method!

State a problem or ask a question that is based on an observation Step 1:

Step 2: Form an hypothesis or make a guess at the solution.

Writing a 3-Part Hypothesis “IF…” (cause) Light causes radish seeds to grow, “AND…” (test) we grow some seeds in the light and some seeds in the dark, “THEN…” (prediction) the seeds grown in the light will grow more than the seeds grown in the dark.

Step 3: Set up a controlled experiment: …only ONE variable should be changed at a time.

The variable that deliberately changed is the manipulated or independent variable.

The variable that is observed or changes in response to the independent variable is the responding or dependent variable.

The control measures the variable’s effect.

The experimental group is the group being measured in the experiment.

Uncontrolled variables will alter the results of an experiment.

4. Collect Data. 5. Analyze data using graphs and charts. 6. Draw conclusions. - evaluate your hypothesis - look for uncontrolled variables - accuracy & precision of data

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Biology is the science… …that seeks to understand the living world.

What do these… …have in common?

All living things on Earth share 8 characteristics!

All living things are composed of units called cells.

All living things obtain and use materials and energy.

All living things grow and develop

All living things are based on a universal genetic code

All living things respond to their environment All living things respond to their environment

A stimulus is a signal to which an organism responds

All living things reproduce …sexual (2 parents) …asexual (I parent)

All living things maintain a stable internal environment This is called homeostasis

Taken as a group, living things change over time. This is called evolution.

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