Which of the following are monoecious and dioecious organisms?
(a) Earthworm ............... (b) Chara ...............
(c) Marchantia ............... (d) Cockroach ...............
(a) Earthworm- Monoecious animal
(b) Chara-Monoecious plant
(c) Marchantia-Dioecious plant
(d) Cockroach- Dioecious animal
Match the organisms given in column I with the vegetative propagules given in column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | Bryophyllum | 1. | Offset |
| B. | Agave | 2. | Eyes |
| C. | Potato | 3. | Leaf buds |
| D. | Water hyacinth | 4. | Bulbils |
$$ \text { The correct matching is as follows } $$
| Column I (Plant Angiosperms) |
Column II (Vegetative Propagules) |
||
|---|---|---|---|
| A. | Bryophyllum | 1. | Leaf buds |
| B. | Agave | 2. | Bulbils |
| C. | Potato | 3. | Eyes |
| D. | Water hyacinth | 4. | Offset |
In plants, the units of vegetative propagation such as runner, rhizome, sucker, tuber, offset, bulb are all capable of giving rise to new offsprings. These structures are called vegetative propagules.
What do the following parts of a flower develop into after fertilisation?
(a) Ovary …….
(b) Ovules ……
(a) Ovary .............. fruit
(b) Ovules ............ seed
After fertilisation, the zygote develops into the embryo and the ovules develop into the seed. The ovary develops into the fruit which develops a thick, protective wall called pericarp.
In haploid organisms that undergo sexual reproduction, name the stage in the life cycle when meiosis occurs. Give reasons for your answer.
Meiosis can take place only in a diploid stage (post-zygotic stage) because the zygote is the only diploid cell in the life cycle of such organisms. This meiosis an case of haploid organisms will occur of the fertilisation.
The number of taxa exhibiting asexual reproduction is drastically reduced in higher plants (angiosperms) and higher animals (vertebrates) as compared with lower groups of plants and animals. Analyse the possible reasons for this situation.
Higher plants (angiosperms) and higher animals (vertebrates) have a more complex structural organisation as compared to the lower groups of plants and animals. They have evolved very efficient mechanism of sexual reproduction. These groups have resorted to reproduction by the sexual method for the following reasons
(i) To ensure healthy progeny
(ii) To produce genetically varied offsprings that adapt to changes in environment and surviveal in all climatic conditions.
(iii) It ensures the genetic recombination that results in variation which gives rise to evolution.