Ch. 1 The Science of Biology

• What is science?• Science: an organized way of using

evidence to learn about the natural world.

• The goal of science is to investigate and understand the natural world and to use those explanations to make useful predictions.

• Thinking like a scientist: begins with observations which gives data,

qualitative or quantitative (numbers)

• Next, questions are asked and answers are considered, which leads to forming a hypothesis: a proposed scientific explanation for data which can be tested!!!

• Scientists collaborate and share data and discuss experiments.–Designing an experiment:

1. Ask a question2. Form a hypothesis3. Set up a controlled experiment

(one variable) 4. Record and analyze data5. Draw a conclusion6. Repeat the experiment!!!!

• Manipulated variable: the one thing that changes in an experiment. (Everything else is the same.)

• Responding variable: the item that changes as a result of the manipulated variable.

• Example: Redi’s experiment

If possible, experiments should have only one manipulated variable, everything else should be kept the same or controlled.

Why are controlled experiments sometimes impossible?

Developing Theories• If a hypothesis is supported by

repeated experimentation, it may become a theory.–A theory is a well-tested explanation

for a broad set of observations.–A theory may need to be changed at

some point in the future to explain new observations or experimental results.

Scientific Laws• A scientific law is a concise

statement that summarizes the results of many observations and experiments. • A scientific law doesn’t try to

explain. That explanation requires a theory.

The Scientific Method

How Science Works

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In reviewHypothesis- an explanationExperiment- tests hypothesisTheory- an explanation that has been verified

by so many different experiments that we agree it is TRUTH.

Scientific Law- states what happens

LAW- Boats disappear on the horizonOld hypothesis- the world is flatCurrent theory- the world is round

Biology: the study of life• Characteristics of living things:–Made of cells–Reproduce (sexual or asexual)–Universal genetic code (DNA)–Grow and develop–Obtain and use material and energy–Respond to their environment–Maintain a stable internal environment

(homeostasis)–Change over time (evolve)

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Figure 1-19 on page 21

LEVELS OFBIOLOGICALORGANIZATION

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THE METRIC SYSTEM

A compound light microscope allows

light to pass through an image and uses two

lenses to form an image.

You can see tiny stuff!

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An electron microscope uses

beams of electrons to form an image.

1000x more powerful!You can see parts of cells & molecules.

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