Concept building short review on Sexual reproduction in flowering plants

1. Why is sexual reproduction important for organisms?

Sexual reproduction is important because:

1. It produces variation
   Offspring are not exactly same as parents. Small differences appear.

2. Variation helps survival
   If environment changes, some organisms can survive better.

3. It helps evolution
   New characters develop slowly over generations.

4. It keeps species strong
   Harmful characters are reduced and useful characters increase.

👉 In short: Sexual reproduction helps organisms survive, adapt, and continue their species.

2. Sexual reproductive structures of higher plants

In higher plants (like flowering plants), the flower is the reproductive part.

(A) Male reproductive structure – Stamen

It has two parts:

1. Anther – produces pollen grains (male cells)
2. Filament – supports the anther

(B) Female reproductive structure – Carpel / Pistil

It has three parts:

1. Stigma – receives pollen
2. Style – connects stigma and ovary
3. Ovary – contains ovules (female cells)

3. Microsporogenesis (formation of pollen grains)

Microsporogenesis means formation of microspores (pollen grains).

Process:

1. It occurs in the anther.
2. Inside anther, there are microspore mother cells (MMC).
3. Each MMC divides by meiosis.
4. Four haploid microspores are formed.
5. These microspores develop into pollen grains.

👉 Pollen grain = male gametophyte

4. Megasporogenesis (formation of ovule)

Megasporogenesis means formation of megaspores.

Process:

1. It occurs inside the ovule in the ovary.
2. A megaspore mother cell (MMC) is present.
3. MMC divides by meiosis.
4. Four megaspores are formed.
5. Only one megaspore is functional, others degenerate.
6. The functional megaspore develops into embryo sac.

👉 Embryo sac = female gametophyte

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🌸 Difference in one line

• Microsporogenesis → produces pollen grains (male)
• Megasporogenesis → produces embryo sac (female)