Ch. 1 Notes

What is Science?

• A body of knowledge based on the study of nature.Goal: to understand and explain events in nature by investigating and predicting future events.

• Scientists gather evidence through careful, organized (systematic) observation and problem-solving = scientific method.

Observation

• Using one or more of the senses to gather information.

• Observations become “Data” or “Evidence.”

• May be direct or indirect (remote sensing)

Data

• Quantitative

involves numbers (size, amount.)

• Qualitative

characteristics that do not involve numbers. (color, texture, etc.)

Interpreting Evidence• Must interpret data for it to be meaningful.

• Inference: a logical interpretation based on prior knowledge and experience.

Ex: smell cookies, feel hot

oven, see crumbs on pan,

infer that someone made cookies.

Hypothesis

• A possible explanation that can be tested by observation or experimentation.

• May come from prior knowledge and logical inferences (cookies).

• Often takes the form “If…, then…because…”

Analyzing Results

• Make tables, charts, graphs to organize data

• Use statistics (math)

to find relationships

in data

Drawing Conclusions• Decide if your results support your hypothesis.

• Repeat the experiment

• Avoid bias: A statistical sampling error caused by favoring some outcomes over others. (double blind studies)Ex: you know one of your siblings did it…the “greedy” one!

Communicate Findings

• Tell the world and other scientists what you found!

Why is this important???

Designing Experiments(Scientific Method)

• Make an OBSERVATION

• State the PROBLEM OR QUESTION

• Form a HYPOTHESIS.

• Set up a Controlled EXPERIMENT.

• Record and Analyze RESULTS.

• Draw a CONCLUSION.

• COMMUNICATE Findings.

Elements of a Controlled Experiment

• Variables:

• Independent variable:

• Dependent variable:

• Controlled Experiment:

Variables:

factors in an experiment that can change.

Ex:

temperature, light, equipment used, type of material, time, etc

Independent variable:

the ONE variable that the experimenter changes. (manipulated variable)

(The “cause” of cause and effect)

Dependent variable:

the variable that is affected by the independent variable. (responding variable)

The variable you measure as a result.

(This is the “effect” of cause and effect.)

Controlled Experiment

• Run a control group that stays the same so that you can compare the experimental group to the control group.

• Moths jamming bats' sonar

What if you can’t experiment?

• Ethically challenging experiments:– Testing new drug on patients.– Testing cancer causing chemical on humans.– Is dental plaque linked to heart disease?

Researchers must design other ways to gather information. Try to control as many variables as possible. Use

• Historical records• Field studies (animal behavior)• Remote sensing

I have a Theory about that…• Theory: a well-tested explanation that unifies

a broad range of observations and allows scientists to make predictions.

The best explanation of all available evidence, but not “absolute truth”.

Ex:

Cell theory, Atom theory, Big Bang theory, Evolution theory, Plate Tectonics, etc.

Universal Laws

• Truths that are valid everywhere in the universe.

Ex: law of gravity, law of conservation of energy

A Scientist is….

1.Curious

2.Honest, Ethical

3.Open-minded

4.Skeptical

5.Recognizes the limits to science

Ethics

• Theory or system of moral values

• Ethical people do the right thing

Skepticism

• A questioning and often doubtful attitude.

Here is a vial with a new drug which will allow you to live to be 110 years old.

Are you skeptical? Why? What evidence would convince you of this claim?

Why is it important for scientists to be ethical?

• Peoples’ lives depend on it.

• Ecosystems depend on it.

• Peer review keeps scientists honest.

Why Should You Pay Attention?

• Because biology is about your life.

• YOU ARE BIOLOGICAL ORGANISMS!

• Have you ever taken antibiotics?

• Do you know someone who has cancer, AIDS, or heart disease?

• Have you thought about drinking, smoking, or taking drugs?

• Do you wonder about where your food has been?

You can change the world!• YOU will be the voting citizens of our

democracy.

• YOUR vote can change policy.

• YOU must know how to interpret science to make informed choices.

• It will be YOUR choice!