Sexual reproduction
Vocabulary
| English | Chinese | Pinyin |
|---|---|---|
| sexual reproduction | 有性生殖 | yǒu xìng shēng zhí |
| gametes | 配子 | pèi zi |
| chromosomes | 染色体 | rǎn sè tǐ |
| fertilisation | 受精 | shòu jīng |
| zygote | 合子 | hé zǐ |
| variation | 变异 | biàn yì |
Mixing two parents
- Most animals and many plants reproduce using two parents.
- This sexual reproduction 有性生殖 mixes genes, creating offspring that are all different.
Practice
Gametes are:
Gametes carry half the chromosomes.
Practice
Each gamete carries ______ the normal number of chromosomes.
Fertilisation restores the full number.
Gametes 配子
- Sexual reproduction involves gametes (sex cells): a male gamete and a female gamete.
- Each gamete has half the normal number of chromosomes 染色体.
The sperm is small and swims; the egg cell is large and stores food
Explore
Sexual reproduction
Two parents each contribute a gamete; fertilisation combines them, creating variation.
Practice
Fertilisation is the:
Two gametes fuse to form a zygote.
Practice
The cell formed when two gametes fuse is called a zygote.
The zygote grows into a new organism.
Fertilisation 受精
- Fertilisation is the fusion of a male and female gamete.
- This restores the full chromosome number and forms a zygote 合子, which grows into a new organism.
Practice
A key advantage of sexual reproduction is that it produces:
Mixing two parents' genes creates variation.
Variation 变异
- Because offspring get genes from two parents, they show variation.
- This variation is the raw material for evolution and helps populations survive change.
Example
Worked example. A sperm (23 chromosomes) fuses with an egg (23 chromosomes) at fertilisation, making a zygote with the full 46. The mix of two parents' genes makes each child unique.
You've got it
Key idea
- sexual reproduction uses two parents and gametes (with half the chromosomes)
- fertilisation = fusion of male and female gametes → a zygote
- it produces variation, helping populations adapt and survive