| Mention the site of zygote formation in the ovule of a flowering plant. What happens to sepals, petals and stamens after fertilisation? State the fate of zygote, ovule and ovary in these plants. | Embryo sacSepals, Petals and Stamens dry and fall off. Zygote develops into embryo. Ovule develops into seed and ovary into fruit. |
| What are heterogametes? What do we call these gametes individually? | Most of the sexually reproducing organisms produce two morphologically distinct gametescalled heterogametes.
The male gamete is called antherozoid or sperm and the female gamete is called egg or ovum. |
| Why is syngamy a major event in sexual reproduction? | The fusion of the male gamete with the female gamete is called syngamy or fertilization andplays and important role in exchange of genetic material to introduce variation and results intoformation of diploid zygote. |
| .What happens during embryogenesis? | Embryogenesis is the development of the embryo. The zygote undergoes mitotic cell division to increase the number of cells. It is followed by cell differentiation where the cells undergo certain modifications to form the specialized tissues and organs to form the organism. |
| .Enlist the changes that occur post- fertilization in plants. | The various post- fertilization changes as observed in plants are
The sepals, petals and stamens wither away.
The pistil remains attached to the plant.
The zygote develops into embryo, ovary develops into fruit and the ovules develop into seeds. |
| Which is better mode of reproduction : Sexual or Asexual? Why? | Sexual reproduction introduces variations in offsprings and has evolutionary significance. It helps offsprings to adjust according to the changes in environment. It produces better offsprings due to character combination. |
