Science · Class 8
Reproduction in Animals
Modes of reproduction in animals; fertilisation and development.
4 sections15–25 min read6 MCQs · 2 examples
Chapter Overview
Sexual reproduction involves fusion of gametes. This chapter covers male and female reproductive systems, fertilisation (internal/external), development of embryo, and metamorphosis.
Human Reproduction
- Males: testes produce sperm; females: ovaries produce eggs
- Fertilisation in fallopian tube — zygote forms
- Embryo implants in uterus; placenta provides nourishment
- Birth after ~9 months gestation
Fertilisation Types
- Internal: sperm deposited inside female body (humans, birds)
- External: eggs fertilised in water (fish, amphibians)
- Viviparous: young born alive; oviparous: lay eggs
Metamorphosis
- Frog: tadpole (aquatic, gills) → adult (lungs, land)
- Silkworm and butterfly: complete metamorphosis
Solved Examples
Step-by-step solutions — read each step before checking the final answer.
Frog life cycle
Describe metamorphosis in frog.
- 1Eggs → tadpole with tail and gills
- 2Gradually legs develop, tail shortens
- 3Adult frog with lungs
Answer
Tadpole to adult transformation
Placenta
What is the function of placenta?
- 1Connects embryo to uterus wall
- 2Transfers nutrients and oxygen from mother
- 3Removes waste from embryo
Answer
Nutrient and gas exchange for embryo
Key Points to Remember
- ✓ Adolescence precedes reproductive maturity
- ✓ Binary fission in Amoeba is asexual
- ✓ Hen is oviparous
Exam Tips
- • Draw human reproductive system (labelled)
- • Compare internal and external fertilisation
- • Draw frog life cycle
Practice MCQs — Reproduction in Animals
Test your understanding with topic-wise multiple choice questions. Explanations appear after each answer.
Question 1 of 6Score: 0/0
Fertilisation in humans occurs in: