Variation In Our World

Overview

Students begin with a brief recap of DNA, genes, alleles, inheritance and phenotype. They then explore variation in humans and other organisms by collecting class data, organising it in a table and representing one variable in a suitable graph. The lesson concludes with a quick classification game linking variation to inherited and environmental causes.

Learning intentions

• Understand that humans vary in their characteristics and traits.

Success criteria

• I can use the terms DNA, gene, allele, genotype and phenotype correctly.
• I can classify examples of variation as continuous or discontinuous.
• I can record class data in a clear table and represent it in an appropriate graph.
• I can explain whether a characteristic is mainly inherited, environmental or influenced by both.

Curriculum links

• Genetics and evolutionary change — the relationship between DNA, inheritance, variation and the diversity of living things.
• Genetics and evolutionary change — explaining how DNA is responsible for transmitting heritable characteristics.
• Data science — using data to assess scientific claims and support evidence-based decisions.
• Working scientifically — communicating scientific arguments with evidence and appropriate terminology.

Lesson structure (60 minutes)

1. 0–5 min · Hook and prior knowledge. Open with the hook and recap slides showing two visually similar organisms with different traits and ask, “Why are individuals of the same species not identical?” Students write one idea, then share with a partner. Teacher gathers responses without correcting them immediately.

2. 5–15 min · Quick recap. Use the recap slides to revisit the basic ideas that genes are sections of DNA, inherited traits are characteristics passed from parents to offspring, and variation means differences between individuals of the same species. Students complete the short recall prompts on the variation worksheet and hold up answers for quick checks. Use simple examples such as eye colour, blood group or earlobes.

3. 15–23 min · Teach variation. Present the variation teaching slides explaining variation as differences between individuals of the same species. Introduce continuous variation, such as height and hand span, and discontinuous variation, such as blood group or tongue-rolling category. Explain that some traits are mainly genetic, some are mainly environmental, and many are influenced by both. Students sort the examples on the worksheet into the three categories and justify one choice.

4. 23–40 min · Class data investigation. Model how to collect respectful, anonymous data for one or two non-sensitive traits, such as hand span, number of siblings, handedness or earlobe type. Do not collect medical, racial, body-weight or other private information. In pairs, students survey the class, record results in the table on the class variation data table and check that units and categories are consistent. Students calculate the range for a measurement variable or total each category.

5. 40–50 min · Table to graph. Return to the graphing instruction slides and model choosing a column graph for categories or a histogram for grouped continuous measurements. Students construct one graph on the worksheet, including a title, labelled axes, units where needed and an appropriate scale. Teacher circulates, checking that students have not joined separate categories with a line and that their graph matches their data.

6. 50–56 min · Variation game. Play “Inherited, Environmental or Both”. Teacher reads or displays examples such as eye colour, language spoken, height, a scar, fur thickness in winter and seed size in plants. Students move to, point to or hold up one of three labels. After each example, invite one student to give a scientific reason; accept “both” where the characteristic has genetic and environmental influences.

7. 56–60 min · Plenary and exit check. Use the plenary slides for three final prompts. Students complete the exit questions on the final reflection questions: define variation, classify height as continuous or discontinuous, and explain how variation can contribute to differences within a species. Collect worksheets as students leave.

Resources

• the variation and inheritance slide deck
• the genetics and variation worksheet
• Projector or interactive display
• Rulers or tape measures for hand-span data
• Pencils, rulers and coloured pencils
• Three labelled response cards or areas: inherited, environmental, both
• Calculator, if required for checking totals or range

Assessment

• Questioning during the recap checks understanding of DNA, genes, alleles, genotype and phenotype.
• Teacher checks students’ data tables and graphs for accurate recording, suitable representation, labels, units and scales.
• Exit responses assess whether students can distinguish types and causes of variation and connect variation to diversity within a species.

Differentiation

• Provide a word bank and sentence starters such as “This is continuous variation because…” and “The characteristic may be influenced by…”.
• Display a completed example of a data table and graph before students begin; allow students to work with a partner.
• For EAL/D and students requiring support, use visual examples, read instructions aloud and provide partially completed axes or category tables.
• Challenge early finishers to compare two variables, identify a possible pattern and explain why the class data cannot represent the whole human population.
• Avoid requiring students to disclose personal or sensitive characteristics; offer fictional or teacher-provided data where appropriate.