Sexual And Asexual Reproduction
Laura Armstrong & Joe Wolfensohn
Teachers
Contents
Recall Questions
This topic requires prior knowledge of fertilisation and mitosis.
What is sexual reproduction?
The joining of male and female gametes to produce genetically different offspring
What is fertilisation?
The fusion of the nuclei of a male and female gamete (e.g., sperm and egg)
How does mitosis relate to asexual reproduction?
Asexual reproduction uses mitosis to produce genetically identical offspring from one parent
Topic Explainer Video
Check out this @JoeDoesBiology video that explains sexual and asexual reproduction, then read the study notes. Once you’ve gone through them, don’t forget to try the practice questions!
Sexual And Asexual Reproduction
Sexual Reproduction
- Involves two parents.
- Gametes (sex cells) such as sperm and egg are produced by meiosis.
- Fertilisation occurs when gametes fuse, creating a zygote.
- Each offspring has genetic variation, inheriting a mix of genes from both parents.
- Examples:
- Animals (e.g., humans)
- Flowering plants (e.g., via pollen and ovules)
Asexual Reproduction
- Only one parent is needed.
- No fusion of gametes, so no mixing of genetic information.
- Offspring are clones (genetically identical to the parent).
- Reproduction occurs via mitosis.
- Examples:
- Bacteria (binary fission)
- Potato tubers
- Strawberry runners
Comparison Table
|
Feature |
Sexual Reproduction |
Asexual Reproduction |
|
Number of Parents |
Two |
One |
|
Gametes Involved |
Yes- they fuse at fertilisation. |
No- no fertilisation. |
|
Genetic Variation |
Yes, genetically different offspring. |
No, genetically identical offspring (clones). |
|
Cell Division Used |
Meiosis to make the gametes. |
Mitosis only. |
|
Examples |
Humans, flowering plants. |
Bacteria, fungi, strawberry plants, daffodils. |
|
Speed |
Slower |
Faster- as no gametes needed and no mating / fertilisation. |
|
Energy required |
Requires more energy- to make gametes and find a mate. |
Requires less energy. |
Key Terms
- Gamete – a sex cell (e.g., sperm or egg).
- Zygote – the fertilised egg.
- Mitosis – type of cell division producing genetically identical cells.
- Meiosis – type of cell division producing gametes with half the number of chromosomes.
- Clone – an organism genetically identical to the parent.
No answer provided.
Exam Tips
When comparing the two types of reproduction, focus on:
- Number of parents.
- Whether gametes and fertilisation are involved.
- Presence or absence of genetic variation.
No answer provided.
Practice Question
Sexual reproduction produces offspring that are genetically different from each other.
Give two reasons why sexual reproduction causes variation in the offspring. (3 marks)
Model Answer:
- Gametes / eggs / sperm are not genetically identical or gametes / eggs / sperm are genetically different.
- Because they are made via meiosis.
- There is mixing of genetic information / genes / DNA from two parents.
More Practice
Try to answer these practice questions from the TikTok videos on your own, then watch the videos to see how well you did!