Biology unit 1- area of study 3 outcome 3

What is an independent variable?

The factor that is deliberately changed or manipulated by the researcher to test its effect on another variable.

What is a dependent variable?

The factor that is measured or observed in response to changes in the independent variable.

What is a controlled variable?

A factor that is kept constant throughout the experiment to ensure a fair test and reliable results.

Why is a control group important in experiments?

It acts as a baseline for comparison, showing the effect of the independent variable by comparing it to a condition where that variable is absent or unchanged.

Give an example of variables in a biology experiment.

In testing the effect of light on plant growth:

• Independent variable: light intensity

• Dependent variable: plant height

• Controlled variables: water, soil type, temperature

What is meant by scientific methodology?

The systematic process used to collect data, test hypotheses, and draw conclusions in scientific investigations.

What are the main types of scientific methodologies?

• Controlled experiment – manipulating one variable while keeping others constant.

• Correlational study – observing relationships between variables without manipulation.

• Classification & identification – sorting organisms or materials based on features.

• Fieldwork – collecting data in a natural environment.

What is the key difference between a controlled experiment and a correlational study?

• Controlled experiment: establishes cause and effect by manipulating variables.

• Correlational study: shows relationships but not direct causation.

Why are replicates important in scientific studies?

They increase accuracy and reliability by reducing random errors and confirming consistency of results.

What is the purpose of classification and identification in biology?

To group and name organisms based on shared characteristics, helping scientists organise and understand biodiversity.

What is an aim in a scientific investigation?

A broad statement of what the experiment is trying to achieve or find out.

What is a hypothesis?

A testable prediction that proposes a relationship between the independent and dependent variables.

What is a model?

A representation or simplification of a system or process to explain how it works (e.g., lock-and-key model for enzymes).

What is a theory?

A well-supported explanation of natural phenomena that has been repeatedly tested and confirmed by evidence (e.g., cell theory, evolution).

What is a scientific law?

A statement that describes consistent, universal patterns in nature, often expressed mathematically (e.g., Law of Conservation of Energy).

How do a theory and a law differ?

• A law describes what happens.

• A theory explains why and how it happens.

How can scientific investigations support or challenge existing theories?

By collecting new evidence that either aligns with current models or contradicts them, prompting model revision (e.g., discovery of DNA structure refined earlier genetic theories).

Why is peer review important in science?

It ensures accuracy, validity, and reliability by having other scientists evaluate and confirm results before publication.

What is primary data?

Data collected firsthand by the researcher through experiments, observations, or measurements.

How is primary data different from secondary data?

• Primary data: collected directly by the researcher.

• Secondary data: collected by others (e.g., from textbooks, published studies).

What makes primary data reliable?

Consistent collection methods, proper calibration of instruments, and minimising human or systematic errors.

How can data be organised and analysed?

• Using tables, graphs, or statistical methods to identify patterns or trends.

• Comparing results to hypotheses or existing theories.

What are sources of error in data?

• Random errors: unpredictable variations (e.g., timing differences).

• Systematic errors: consistent bias from equipment or method flaws.

• Human errors: mistakes made by experimenters.

Why is identifying errors important?

It improves accuracy and validity, helping to explain inconsistencies or limitations in results.

What is a scientific logbook?

A record of all procedures, observations, data, and reflections kept during an investigation.

Why is a logbook essential?

It authenticates data, ensures transparency and repeatability, and provides a reference for evaluation or peer review.

What are limitations in scientific investigations?

Factors that restrict accuracy, reliability, or generalisability of results (e.g., sample size, uncontrolled variables, or measurement precision).

Why should limitations be acknowledged?

It allows for critical evaluation of findings, helps refine future experiments, and maintains scientific honesty.