Question 1.
Fill in the blanks:
- Production of new individuals from the vegetative part of a parent is called ……….
- A flower may have either male or female reproductive parts. Such a flower is called ……….
- The transfer of pollen grains from the anther to the stigma of the same or of another flower of the same kind is known as ………..
- The fusion of male and female gametes is termed as ……….
- Seed dispersal takes place by means of ………., ………. and…………….
Solution:
- vegetative propagation
- unisexual flower
- pollination
- fertilization
- wind; water; animals.
Question 2.
Describe the different methods of asexual reproduction. Give examples.
Solution:
Various methods of asexual reproduction are:
- Vegetative propagation: When new plants are obtained from leaves, stems, and roots, it is called vegetative propagation, e.g., in rose, sugarcane, potato, ginger (stem), Bryophyllum (leaf), sweet potato, Dahlia (roots) and any detached body part of cacti.
- Budding: Reproduction in yeast is by budding. The small bulb-like projection called bud comes out from the parent cell. The bud gradually grows and gets detached from the parent cell and forms a new yeast cell.
- Fragmentation: Some organisms like Spirogyra break up into two or more fragments and each fragment develops into a new plant.
- Spore formation: The spores are the asexual reproductive parts which are covered by a protective covering to withstand unfavorable conditions. Under favourable conditions, the spore germinates and develops into a new individual.
Question 3.
Explain what you understand by sexual reproduction.
Solution:
Sexual reproduction means the involvement of two parents in the process of reproduction. It is found mainly in higher plants, where male gamete and female gamete fuse to form a zygote. These zygotes develop into individuals which are not identical. Offsprings inherit the characteristics of both parents. In sexual reproduction, both parents survive after the process of reproduction.
Question 4.
State the main difference between asexual and sexual reproduction.
Solution:
In sexual reproduction, the seed is required but in asexual reproduction, the seed is not required.
Question 5.
Sketch the reproductive parts of a flower.
Solution:
Question 7.
How does the process of fertilization take place in flowers?
Solution:
Pollen grain reaches on the stigma of a carpel by pollination. On the stigma, the pollen grain germinates and a pollen tube comes out. This pollen tube grows and approaches through the style to the ovary, carrying male gametes with it, where it enters the ovule. Inside the ovule, there is a female gamete or egg. The male gamete fuses with the female gamete. This process is called fertilization.
Question 8.
Describe the various ways by which seeds are dispersed.
Solution:
Seeds are dispersed to different places in the following ways:
- By wind: Seeds dispersed by wind are either winged (e.g., drumstick and maple) or light (e.g., grasses) or hairy (e.g., aak and sunflower).
- By water: Seeds dispersed by water develop floating ability (e.g., coconut).
- By insects and other animals: Seeds which are spiny (e.g., Xanthium and Urena) have hooks and get attached to the body of animals or to clothes of passers-by. They are self carried to different places.
- Some seeds are dispersed when the fruit bursts with sudden jerks (e.g., castor and balsam).
Question 9.
Match items in Column I with those in Column II :
Column I | Column II |
(a) Bud | (i) Maple |
(b) Eyes | (ii) Spirogyra |
(c) Fragmentation | (iii) Yeast |
(d) Wings | (iv) Bread mould |
(e) Spores | (v) Potato |
(vi) Rose |
Solution:
(a)-(iii)
(b)-(v)
(c)-(ii)
(d)-(i)
(e)-(iv).
Question 10.
Tick (✔) the correct answer:
(a) The reproductive part of a plant is the ___________
(i) leaf
(ii) stem
(iii) root
(iv) flower
(b) The process of fusion of the male and the female gametes are called __________
(i) fertilization
(ii) pollination
(iii) reproduction
(iv) seed formation
(c) Mature ovary forms the
(i) seed
(ii) stamen
(iii) pistil
(iv) fruit
(d) A spore-producing plant is __________
(i) rose
(ii) bread mould
(iii) potato
(iv) ginger
(e) Bryophyllum can reproduce by its ____________
(i) stem
(ii) leaves
(iii) roots
(iv) flower
Solution:
(a) – (iv) flower
(b) – (i) fertilization
(c) – (iv) fruit
(d) – (ii) bread mould
(e) – (ii) leaves