Science lesson plan · 6th grade (Year 7 in England) · 45 minutes
Continuous and discontinuous variation
Cells, genetics and evolution
CCSS NGSS.MS-LS3-2CCSS NGSS.SEP 4England: KS3 Biology: Inheritance, chromosomes, DNA and genes
Objective and success criteria
Students will: Continuous and discontinuous variation.
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: Inherited and environmental characteristics
Leads to: Use twins and clones to separate genes from environment
Materials: Microscope images or slides, Cell diagrams, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).
Warm-up · 5 min
- Quick retrieval from earlier learning (Inherited and environmental characteristics). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Is this characteristic inherited or environmental: natural eye colour? (inherited (from parents) / environmental (from life)) → inherited (from parents)Prompt: Were you born with it, or did it happen during life?
- A plant grown in a dark cupboard is tall, thin and pale. Its seeds are planted in sunlight. The new plants are… (pale, because they inherit it / normal and green, because the pale look was caused by the environment / white, because their parent was in the dark / unable to grow) → normal and green, because the pale look was caused by the environmentPrompt: Is being pale passed on in the seeds?
- Inheritance: which statement is true? (Characteristics are passed on in genes. / Children are always exact copies of one parent. / If a parent loses a finger, its babies are born without that finger. / The language you speak is inherited.) → Characteristics are passed on in genes.Prompt: Which things can be passed on in genes?
Hook · 5 min
- Show a microscope image of cells and ask what students think they are looking at.
- Share the objective: Continuous and discontinuous variation. Read the success criteria together.
I do: model it · 10 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: Is this continuous or discontinuous variation: height?
- Step 1: Continuous variation can take any value in a range, so it is measured.
- Step 2: So the answer is: continuous
- Answer: continuous
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 10 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- Is this continuous or discontinuous variation: body mass? (continuous / discontinuous) → continuousPrompt: Can it have any value, or only a few set categories?
- Five students measured their heights in cm: 169, 161, 185, 141, 154. What is the range of their heights, in cm? → 44 cmPrompt: The range shows how spread out the data are.
You do: independent practice · 10 min
- Students work on the student sheet. Circulate and check the first two answers of every student early.
- Students who finish: write a question of their own for a partner, with the answer.
The 8 questions are on the student sheet below, with answers in the key.
Exit ticket · 5 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Which of these is an example of discontinuous variation? (ABO blood group / heart rate / arm length / body mass) → ABO blood groupPrompt: Which one has only a few fixed categories?
- Is this continuous or discontinuous variation: pea seed shape (round or wrinkled)? (continuous / discontinuous) → discontinuousPrompt: Can it have any value, or only a few set categories?
Watch out for
- Everyday meanings of words getting in the way of the science meaning: define key words explicitly.
- Remembering facts without the reason: ask "why?" and "what is the evidence?"
Support and stretch
Support
- Review first: Inherited and environmental characteristics.
- Use concrete materials: microscope images or slides.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Move on to: Use twins and clones to separate genes from environment.
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-6.
Free lesson plan from eurekami.com/lesson-plan-builder