Reproduction

Reproduction

What Is Reproduction?

Reproduction is the process by which organisms produce offspring. There are two main types:

  • Asexual reproduction – one parent, offspring are genetically identical (clones).
  • Sexual reproduction – two parents, offspring show genetic variation.

💡 Key Concept: Sexual reproduction introduces variation, which is important for evolution.

Asexual vs Sexual Reproduction

Feature

Asexual Reproduction

Sexual Reproduction

Number of parents

1

2

Genetic variation

None – clones

Yes – unique combination of genes

Gametes involved?

No

Yes – sperm and egg cells

Cell division

Mitosis

Meiosis

Examples

Bacteria, some plants, fungi

Animals, flowering plants

Gametes in Sexual Reproduction

Gamete

Produced By

Function

Sperm cell

Testes (male)

Carries half the father’s DNA to fertilise the egg.

Egg cell (ovum)

Ovaries (female)

Carries half the mother’s DNA and nutrients for embryo.

Fertilisation

✔ When a sperm fuses with an egg → a zygote is formed.
✔ The zygote then divides by mitosis to develop into an embryo.

Advantages and Disadvantages

Sexual Reproduction

✔ Produces variation – useful for adapting to changing environments.
❌ Takes more time and energy; needs a mate.

Asexual Reproduction

✔ Faster, efficient, no need for a mate.
❌ No variation – vulnerable to disease and environmental change.

Organisms That Can Reproduce Both Ways

Some organisms can switch between types of reproduction:

  • Malaria parasites – asexual in human, sexual in mosquito.
  • Fungi – spores by asexual or sexual methods.
  • Strawberry plants – runners (asexual) and seeds (sexual).

Questions 

  1. What is the main difference between sexual and asexual reproduction?
  2. What type of cell division occurs in asexual reproduction?
  3. What is fertilisation?
  4. Why is variation an advantage in sexual reproduction?
  5. Name one organism that can reproduce both sexually and asexually.

Summary 

  • Asexual reproduction is fast and produces clones (via mitosis).
  • Sexual reproduction involves gametes and fertilisation, leading to genetic variation.
  • Some organisms can switch between both types depending on conditions.
  • Variation is important for evolution and survival.