KS3 · Biology

Heredity: passing on traits

Pick a feature in the mirror: eye colour, a scar, your height. Did it come from your parents, from what's happened to you, or both?

Have a go first

Could it be passed on?

Genetic material is the set of instructions in your cells that parents pass to their offspring. For each feature, tick the circle it belongs in: caused by those instructions (inherited), caused by environment or lifestyle, or both if both play a part.

  • A Caused by instructions in genetic material (inherited)
  • B Caused by environment or lifestyle
  1. Eye colour
  2. Blood type
  3. A scar
  4. A piercing
  5. A tattoo
  6. Height
  7. Body mass
  8. Hair colour
  9. Skin colour

Passing it on, one generation to the next

Step through it. Each stage hands something on to the next.

Two kinds of 'looks like its parents'

Species resemblancevsFamily resemblance

They sound alike. They aren't the same idea.

Focus

What offspring share

Species resemblance

They are the same kind (species) as their parents

Family resemblance

They look similar to both of their parents

The insight

One is about the kind of living thing it is. The other is about its own mum and dad.

When you see it

Species resemblance

At some point in the life cycle

Family resemblance

In the combination of features the offspring inherit

Example

Species resemblance

Two cats reproduce and the kittens are cats

Family resemblance

A baby looks similar to both Mum and Dad

What it comes from

Species resemblance

Organisms reproducing, so the offspring are the same kind

Family resemblance

Genetic material from both parents, half from each

Make your call first

Two siblings, the same two parents, not twins.

Maya and her brother Leo have the same two parents and are not twins. Will they look identical?

Which idea is yours?

Three ideas that sound reasonable

A baby called Rosa is born. Her family is chatting about where her features came from.

Which idea is closest to what you think right now?
How sure are you?

WHAT YOU'VE LEARNED

A quick recap of today's lesson.

Your parents, your surroundings, or a bit of both

What you need to know

  • Heredity is how features get passed from parents to their offspring through reproduction.
  • Reproduction is making offspring, the young that follow, and species do it at some point in their life cycle.
  • Offspring are the same kind (species) as their parents and resemble them at some point in their life cycle.
  • Genetic material is a chemical substance in cells that holds instructions for features and life processes like growth and respiration.
  • Offspring get half their genetic material from one parent and half from the other.
  • So offspring look similar to both parents, and a baby doesn't inherit all of its features from its mother.
  • Have a goDev announces: 'My baby cousin's features are all from her mum. Her dad just turned up.' What would you tell Dev?

    She gets half her genetic material from each parent, so her features come from both.

    A baby inherits a combination of features from both parents, so it never gets all of its features from its mother.

  • Only features caused by instructions in genetic material can be inherited, like eye colour or blood type, and parents can't choose which.
  • Features caused by environment or lifestyle, like scars, piercings and tattoos, cannot be inherited.
  • Have a goJade gets a tattoo, then later has a baby. Will the baby be born with Jade's tattoo?

    No. A tattoo can't be inherited.

    A tattoo is caused by environment or lifestyle, not instructions in genetic material, and only features caused by those instructions can be inherited.

  • Height, body mass, hair colour and skin colour are often a combination of heredity and environment or lifestyle.
  • Have a goHair colour, eye colour, skin colour, body mass: how many of these are often a combination of heredity and environment or lifestyle?

    Three: hair colour, skin colour and body mass.

    Eye colour is the example of a feature caused by instructions in genetic material; the other three are often a combination.

  • Siblings inherit different combinations, so they look similar but not identical (except identical twins); differences like this are variation.

The big picture

Heredity is how genetic material passes from both parents to their offspring when they reproduce. Only features caused by instructions in genetic material can be inherited. Features caused by environment or lifestyle cannot, and many physical features are a combination of both.

Key points

1Heredity is the process by which genetic material is passed from parents to offspring in reproduction.
2Offspring receive half of their genetic material from one parent and half from the other, so features come from both parents.
3Only features caused by instructions in genetic material can be inherited; features caused by environment or lifestyle cannot.
4Height, body mass, hair colour and skin colour are often a combination of heredity and environment or lifestyle.
5Siblings look similar but not identical (except identical twins) because each inherits a different combination; differences between individuals are variation.

Worked example

Problem

Aisha says: 'Biscuit the dog has floppy ears and his owner Sam has a tattoo. You can see both, so both must be inherited.' Decide whether each is inherited, and say what's wrong with Aisha's rule.

⚠ Watch out

Thinking anything about a parent can be passed on (a scar, a tattoo), or that a baby's features come from its mother. Only features caused by instructions in genetic material are inherited, and they come from both parents.

🧠

Memory hook

Born with it, picked it up, or a bit of both: inherited, environment or lifestyle, or a combination.

✓

Check yourself

Sam has brown eyes and a scar on one knee. Could Sam's child inherit either one? Say why for each.

Flashcards

(14)
What is heredity?
The process by which genetic material is passed from one generation to the next: organisms pass on features to their offspring through reproduction.
What is reproduction?
The process of making offspring. It is one of the seven common processes of living organisms, and species reproduce at some point in their life cycle.
What are offspring?
The young produced following reproduction.
What is species resemblance?
Offspring are the same kind (species) as their parents, and resemble them at some point in their life cycle.
What is family resemblance?
Offspring inherit a combination of features from both parents, so they look similar to both of them.
What is genetic material, and what does it do?
A chemical substance in the cells of all organisms. It provides instructions for visible features and for life processes such as growth and respiration.
How much genetic material does an offspring get from each parent?
Half from one parent and half from the other.
Which features can be inherited?
Only features caused by instructions in genetic material, for example eye colour or blood type.
Can parents choose which features their offspring inherit?
No. Parents cannot choose which features their offspring inherit.
What do 'environment' and 'lifestyle' mean?
Environment is an organism's surroundings and conditions, such as sunlight, pollutants or availability of nutrients. Lifestyle is what it does and the choices it makes, such as diet and exercise.
Why can't scars, piercings and tattoos be inherited?
They are caused by environment or lifestyle, not by instructions in genetic material.
Which physical features are often a combination of heredity and environment or lifestyle?
Height, body mass, hair colour and skin colour.
What are siblings, and how do they look?
Offspring of the same parents. Each inherits a different combination of features, so they look similar but not identical, except identical twins.
What is variation?
Differences between individuals of the same species. Usually offspring vary and are not identical to their parents or to one another.

Tap any card to flip it, or use Study as deck to go through them one at a time. In the full lesson these run as a spaced-repetition deck — you rate each card Hard, Good or Easy and the tricky ones keep coming back until they stick.

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How this lesson was checked. This KS3 Biologylesson was published through Lightbulb Learning's human-designed editorial process — the educational standards, accuracy rules and publication checks it must pass were authored and approved by Philip Halpin. It passed subject-specific assessment, automated educational checks and technical publication verification before going live (publication checks completed 9 October 2026). Published pages are monitored, human spot-checking is ongoing across the lesson library, and anything found wrong is corrected or withdrawn. How our lessons are made and checked. Spotted a mistake? Email hello@lightbulblearning.co and we'll review it.