Nature of Science

Key skills

Content is only half of Biology. These five skills run through every strand, through the written exam and through the Investigation that is worth 40%. Each one below sets out what it means, what earns the marks, and where on this site to practise it.

Scientific investigation and experimental design

Turning a question into a fair test you can actually carry out, then judging how well it worked.

What it means

•Write a testable hypothesis and state the prediction it makes.
•Name the independent variable you change, the dependent variable you measure, and the variables you keep constant.
•Include a control so you can show the result came from the factor you changed.
•Repeat readings and average them, and describe the safety precautions you took.

What the examiner looks for

•One variable changed at a time, everything else fixed and named
•A control that would give a known or negative result
•Enough method detail that another student could repeat it
•Honest evaluation: sources of error, how reliable the data is, one clear improvement

Practical investigations Scientific investigation notes The 40% Investigation

Use of models and diagrams

Reading, drawing and explaining the diagrams and models biologists use to represent things we cannot see directly.

What it means

•Draw clear, labelled biological diagrams with a title, ruled label lines and no shading.
•Read a diagram you have never seen before and identify the structures from their features.
•Explain what a model shows and, just as importantly, where it breaks down.
•Use models such as the induced fit model, the cohesion-tension model, Punnett squares and food webs to predict outcomes.

What the examiner looks for

•Labels spelled correctly and lines touching the structure they name
•Magnification or scale recorded on microscope drawings
•Structure linked to function, not just named
•A stated limitation when asked to evaluate a model

Interactive simulations Exam diagram bank Punnett square builder

Use of primary and secondary data

Collecting your own measurements, finding trustworthy published data, and presenting both properly.

What it means

•Primary data is data you collect yourself in the lab or the field. Secondary data comes from published sources such as textbooks, the EPA, the CSO or scientific papers.
•Record raw data in a table with headings, units and a sensible number of decimal places.
•Choose the right graph: bar chart for categories, line graph for a continuous independent variable, scatter for a relationship.
•Reference every secondary source you use, and say why you judged it credible.

What the examiner looks for

•Units in table headings, not beside every number
•Axes labelled with quantity and unit, sensible scale, independent variable on the x-axis
•Calculated values such as averages, rates and percentage change shown with working
•Clear distinction between what you measured and what you read

Habitat study techniques Practical investigations Past exam papers

Critical thinking and evaluation

Weighing evidence, spotting weaknesses in a study and deciding how far a conclusion is actually justified.

What it means

•Separate an observation from an inference, and a correlation from a cause.
•Judge whether the sample size, the controls and the repeats are good enough to support the claim.
•Identify bias, anomalous results and the limits of the equipment used.
•Explain why scientific ideas change when new evidence appears, and why peer review matters.

What the examiner looks for

•Conclusions worded to match the evidence, for example supports rather than proves
•Named sources of error with their likely effect on the result
•A balanced answer that gives both sides before reaching a judgement
•Use of the verbs evaluate, justify and discuss in the way the specification defines them

Action verbs glossary Nature of Science Mock exam

Applying biology to social, ethical and environmental issues

Connecting the biology on the course to real decisions people, governments and industries have to make.

What it means

•Use biological knowledge to discuss issues such as vaccination, antibiotic resistance, genetic testing, GM crops and IVF.
•Set out environmental impacts: pollution, eutrophication, biodiversity loss, climate change and conservation.
•Recognise that ethical questions have no single right answer, and argue a position from evidence.
•Describe how biology supports sustainability, food security, medicine and the bioeconomy in Ireland.

What the examiner looks for

•A named, specific example rather than a general statement
•The underlying biology explained before the opinion is given
•Both benefits and risks considered, with a reasoned conclusion
•Reflection on science in society, which is one of the descriptors used to mark the Investigation

Human impact on the environment Genetic technologies and genomics Microorganisms and nutrient cycling