Biology and Scientific Methods: AP Biology Key Concepts and Data Analysis

Biology

Study of life.

Cell

The most basic unit of life.

Biological organization

Shows how properties change as you observe different levels.

Eukaryotic cells

Cells that have a nucleus.

Prokaryotic cells

Cells without a nucleus.

Qualities shared by all cells

Enclosed by a membrane and use DNA as genetic information.

Unicellular organism

Organism made of only one cell.

Multicellular organism

Organism made of more than one cell.

Three domains of life

Bacteria (prokaryotes), Archaea (prokaryotes), Eukarya (eukaryotes).

Characteristics of Life

1. Grow and Develop

2. Respond to Stimuli

3. Reproduce

4. Obtain and Use Energy

5. Have a genetic code

6. Has Cells

Homeostasis

The ability of an organism to regulate a stable internal environment within a certain range.

Evolution

Change over time.

Hypothesis

Educated guess that must be consistent with what's already known and capable of being tested.

Null Hypothesis (H0)

There is no significance between the expected and observed data.

Alternative Hypothesis (H1)

Hypothesis the researcher tries to test. Proposed scientific explanation for the experiment that opposes the null hypothesis.

Controlled Experiment

Variable is unchanged, baseline that lets us see if the treatment has an effect.

Fact

An observation that can be repeatedly confirmed.

Positive Control Group

Experiment with definite results from the variable.

Negative Control Group

Experiment where no response to the variable occurs.

Independent Variable

The part of the experiment that you change.

Dependent Variable

The part of the experiment that changes as a result of the manipulation.

Theory

Explains 'how' and 'why' something happens.

Law

Explains 'what' happens without explaining how.

Metric or SI system

Base 10 system used in science.

Length

Distance between two points.

Mass

Amount of matter an object has.

Kilogram

Unit of mass in the metric system.

Temperature

Amount of energy.

Kelvin

Unit of temperature in the metric system.

Control (Negative and Positive)

A standard for comparison in an experiment.

Constant (controlled variables)

Variables that are kept the same throughout an experiment.

Quantitative Data

Data that can be measured and expressed numerically.

Qualitative Data

Data that describes qualities or characteristics.

Results and Conclusion

The outcome of an experiment and the interpretation of that outcome.

Line vs Bar Graph

Types of graphs used to represent data.

Hypothesis vs Theory vs Law vs Fact

Different levels of scientific understanding.

Error bars

Graphical representation of the variability of data.

P values

Measure of the strength of evidence against the null hypothesis.

Chi Square Test

Equation to analyze if differences in data are due to chance or a variable being tested.

Degrees of Freedom

n - 1, where n is the number of outcomes.

Critical value

The cut-off value found using the Chi Square Chart.