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Biology

Biology is the scientific study of life.

The Scientific Method

the systematic process scientists use to investigate questions

Hypothesis

A proposed explanation based on an observation of why certain events take place.

Experiment

A test of a hypothesis.

Quantitative data

Numerical measurements made using scientific instruments.

Qualitative data

Descriptive observations made by the person carrying out the experiment.

Scientific theory

An explanation of observations supported by many hypotheses.

Scientific law

A description of observed occurrences based on repeatedly proven theories.

Science as a global enterprise

Science depends on clear communication and international conventions.

SI system

Scientists use international conventions such as the SI system for measurements.

Peer review

Scientific research is reviewed by other scientists before it is published in scientific journals or books.

Repeatability

The same person carries out the same experiment, following the same method, and gets the same results.

Reproducibility

Different people follow the same method in different laboratories and get the same results.

Why are these important?

Repeatability and reproducibility help ensure that scientific results are reliable.

Investigations in Biology

Variable

Something that can be changed.

Fair test

An investigation in which only one variable at a time is changed while all other conditions are kept the same.

Control experiment

An experiment used as a standard for comparison against the experimental results.

Independent variable

The variable that is changed.

Dependent variable

The variable that is measured.

Control variables

Variables that are kept constant.

Reliability

The consistency of data when an experiment is repeated.

Improving reliability

Repeat the experiment several times and use a large sample size.

Accuracy

How close measurement values are to the true or accepted value.

Improving accuracy

Use properly calibrated equipment and avoid human error when reading measurements.

Precision

How close repeated measurements are to each other.

Improving precision

Use equipment that measures with fine detail.

Anomalous data

Data that is inconsistent with the other data values.

Error

The difference between the measured value and the true value.

Random error

Unpredicted variation in measurements.

Systematic error

Consistent error caused by a problem in the method followed or in the equipment used.

Integrity

Acting honestly and ethically when conducting and reporting scientific investigations.

Ethics

Rules about what is right and wrong when carrying out scientific investigations.

Scientific model

A simplified representation used to help us visualise, explain and understand biology concepts and to make predictions about results of physical and chemical processes.

Models can

Bridge the visible and invisible; create simplified representations; be modified over time; and help make predictions.

Communicating science

Scientists must explain their work clearly, check that information is trustworthy, evaluate information sources, and recognise and avoid bias.

Primary data

Data collected by the researcher themselves.

Secondary data

Data collected by someone other than the researcher.

Ways to reduce bias

Randomly select participants, use a large sample size, repeat the investigation, use a control experiment, and carry out double-blind testing.

Double-blind test

Neither the scientist nor the participants know which sample contains the active medication and which contains the placebo.

Placebo

A substance with no active medication used in a double-blind test for comparison with the active medication.