OCR · A-Level · Biology
Course version: H420 · Version from Sept 2025
Cloning and biotechnology: (c) natural clones in animal species
A clone is a genetically identical organism or group of cells derived from a single parent or original cell.
Checked against the OCR H420 specification (opens in a new tab) on .
- Point 4 of 10
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
A clone is a genetically identical organism or group of cells derived from a single parent or original cell. Natural cloning occurs in animals in several ways. Identical (monozygotic) twins form when a single fertilised egg divides and the two embryos develop separately; they are clones of each other because they arose from one zygote, though they are not identical to either parent. Some animals reproduce asexually, for example by budding or fragmentation, producing offspring genetically identical to the parent. Learners should distinguish these: identical twins are clones of each other from one fertilised egg, whereas asexual reproduction produces clones of the parent. A question may ask how a named example arises or whether offspring are genetically identical to the parent.
What earns the marks
- A clone is genetically identical to the organism or cell it derives from.
- Identical (monozygotic) twins arise when one fertilised egg divides into two embryos, so the twins are clones of each other.
- Identical twins are not genetically identical to either parent, because they formed from a zygote produced by two parents.
- Asexual reproduction such as budding or fragmentation produces offspring that are clones of the parent.
- Natural cloning in animals can be distinguished from sexual reproduction by whether genetic material from two parents is combined.
Common mistakes and how to put them right
Claiming identical twins are clones of their parent.
Put it right: They are clones of each other, formed from one fertilised egg produced by two parents.
Saying all natural animal clones arise without any contribution from two parents.
Put it right: Identical twins arise from a zygote formed by fusion of gametes from two parents.
Confusing a clone with an organism that merely resembles its parent, rather than one that is genetically identical to the source cell or organism.
Exam tips
- State precisely what a clone is genetically identical to: the parent cell, the parent organism, or the other twin.
- For identical twins, explain that one zygote divided, so the twins are clones of each other, not of a parent.
- Contrast asexual cloning, where offspring are clones of the parent, with identical twins, which are clones of each other.
Try the lesson
The start of the Cloning and biotechnology: (c) natural clones in animal species lesson, made from checked teaching notes for this specification point.
Have a go first
In which animal group is parthenogenesis a naturally occurring route to producing offspring?
Listen
A clone is a genetically identical organism or group of cells derived from a single parent or original cell. Natural cloning occurs in animals in several ways. Identical (monozygotic) twins form when a single fertilised egg divides and the two embryos develop separately; they are clones of each other because they arose from one zygote, though they are not identical to either parent. Some animals reproduce asexually, for example by budding or fragmentation, producing offspring genetically identical to the parent. Learners should distinguish these: identical twins are clones of each other from one fertilised egg, whereas asexual reproduction produces clones of the parent. A question may ask how a named example arises or whether offspring are genetically identical to the parent. A strong answer earns marks for these points. A clone is genetically identical to the organism or cell it derives from. Identical (monozygotic) twins arise when one fertilised egg divides into two embryos, so the twins are clones of each other. Identical twins are not genetically identical to either parent, because they formed from a zygote produced by two parents. Asexual reproduction such as budding or fragmentation produces offspring that are clones of the parent. Exam tip: State precisely what a clone is genetically identical to: the parent cell, the parent organism, or the other twin.
See it
Key words
Say what each word means before you turn the card.
Clone
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Identical twins
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Asexual reproduction
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Natural cloning in animals
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See every definition
- Clone
- A genetically identical organism or group of cells derived from a single parent or original cell.
- Identical twins
- Clones of each other that form when a single fertilised egg divides and the two embryos develop separately.
- Asexual reproduction
- Reproduction such as budding or fragmentation that produces offspring genetically identical to the parent.
- Natural cloning in animals
- Cloning that occurs naturally, distinguished from sexual reproduction by whether genetic material from two parents is combined.
Label the diagram
Some boxes have lost their names. Pick the right name for each number.
1Box 1
2Box 2
3Box 3
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