Chapter 2: Variation within a species
No two wild snow leopards have exactly the same rosette pattern. Variation is the raw material on which environments act.
Part of your national curriculum
- Biology: genetics and evolution: Understand differences between species and the variation between individuals of the same species
Lesson overview
What you'll learn in this lesson
Understand differences between species and the variation between individuals of the same species
Key learning points
- • Continuous variation
- • Discontinuous variation
- • Between and within species
- • Sampling fairly
This lesson at a glance
- 28 minutes
- 15 parts to scroll through
- 3 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 15
Watch first
Chapter 2: Variation within a species
An English teaching video on this topic from FuseSchool - Global Education. Watch it, then scroll down for the lesson.
In a nutshell
Understand differences between species and the variation between individuals of the same species
Learning cycle
Part 2 of 15
Learning cycle 1 of 2
Part 1 · Continuous variation
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 15
Learn
Continuous variation
Characteristics such as height, mass and paw length can take any value across a range. They are often controlled by many genes and affected by the environment, so a histogram shows a spread of measurements.
Explore the idea
Part 4 of 15
Learn
Discontinuous variation
Characteristics such as human ABO blood group fall into separate categories with no values between them. They are usually controlled by one or a small number of genes.
Quick check
Part 5 of 15
Quick check
Which is continuous variation?
Quick check
Part 6 of 15
Quick check
Why should a sample be selected randomly?
Reset break
Part 7 of 15
Pause
That's sitting 1 of 2 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Learning cycle
Part 8 of 15
Learning cycle 2 of 2
Part 2 · Between and within species
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 9 of 15
Learn
Between and within species
Members of different species have defining differences and normally cannot produce fertile offspring together. Members of one species still vary because of inherited alleles, environmental effects and their interaction.
Explore the idea
Part 10 of 15
Learn
Sampling fairly
To compare variation, define the population, choose a representative sample, use the same measuring method and record units. A larger random sample usually gives a more reliable picture.
Quick check
Part 11 of 15
Quick check
What can cause variation within one species?
Challenge round
Part 12 of 15
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Challenge round
Part 13 of 15
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
Members of different species have defining ____ and normally cannot produce fertile offspring together.
Members of one ____ still vary because of inherited alleles, environmental effects and their interaction.
To compare ____, define the population, choose a representative sample, use the same measuring method and record units.
Mastery quiz
Part 14 of 15
Marked quiz
End of lesson quiz: Chapter 2: Variation within a species
3 questions, marked with the reasoning shown. No timer.
1. Which is continuous variation?
2. Why should a sample be selected randomly?
3. What can cause variation within one species?
Lesson round-up
Part 15 of 15
Lesson round-up
Ready when you are
Quiz score
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Luna: 0 out of 3 on the practice checks. Only if you feel up to it — one more?
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Your written work for this lesson
This is the part you'd do in your book at school. Pick the pieces below, write here or on paper, and photograph anything you draw or work out.
Why the school greenhouse failed
A science club grew tomato plants in the school greenhouse. In June the plants grew well: leaves were dark green and the fruit set quickly. In July the club went away for two weeks and left the greenhouse door shut. When they came back, the leaves were curled and pale and most of the fruit had dropped.
The club had a data logger inside. It showed the temperature reached 46 °C on several afternoons and the soil moisture fell close to zero. The club knew photosynthesis needs light, water and carbon dioxide, and that enzymes in a plant work best in a narrow range of temperature. Above that range the enzymes stop working properly.
The club repeated the summer with the door propped open and a water bottle drip on each pot. Temperature peaked at 31 °C and the plants survived.
Written for Good Learning Co.
Reading questions
- Name the variable the club changed the second time, and one variable they kept the same.
- Explain, using the words photosynthesis and enzymes, why the plants were damaged in July.
- Write a conclusion for the club's report, saying how far the evidence supports it.
Method and results
WritingWrite the aim, what you changed, what you measured and what you kept the same, then record your results in a table.
1 page + results table
Conclusion
WritingExplain what your results show and why, using the scientific words from the lesson. Say how you know you can trust them.
6–8 sentences
Labelled diagram
DiagramDraw the apparatus or the process in pencil, label it fully, and photograph it.
1 labelled diagram
Reading and notes
ReadingRead the lesson text again and write the key ideas in your own words.
Half a page of notes
Saved as you type.
Part 1 of 15 · Watch & discover
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Understand differences between species and the variation between individuals of the same species