4.3.4 Meiosis in Animal & Plant cells

Meiosis in Animals

1. Purpose:

• Produces haploid gametes (sperm and egg cells) necessary for sexual reproduction.

2. Where It Occurs:

• Takes place in the gonads (testes in males and ovaries in females).

3. Key Process:

• Meiosis forms four haploid gametes that are genetically different from one another due to independent assortment and crossing over.
• These gametes directly participate in fertilisation to form a zygote.

Meiosis in Plants

1. Purpose:

• Produces haploid spores (not gametes) that develop into gametophytes.
• Gametes are formed later by mitosis within the gametophyte.

2. Where It Occurs:

• In the sporangia (structures such as anthers in flowering plants or spore-producing organs in ferns).

3. Key Process:

• Meiosis generates haploid spores, which grow into the gametophyte stage of the plant life cycle.
• The alternation of generations is observed:
• Diploid sporophyte produces haploid spores by meiosis.
• Haploid gametophyte produces gametes by mitosis.

Differences Between Animals and Plants

Feature	Animals	Plants
Product of Meiosis	Haploid gametes (sperm and egg)	Haploid spores
Role of Gametes	Gametes directly participate in fertilisation	Gametes formed by mitosis in gametophyte
Location	Gonads (testes and ovaries)	Sporangia (e.g., anthers)
Life Cycle	No alternation of generations	Alternation of generations occurs