Chapter 6 - Classification of plants
1. Match the proper terms from columns A and C with the description in column B.
| ‘A’ | ‘B’ | ‘C’ |
|---|---|---|
Thallophyta | Seeds are formed in fruits | Fern |
Bryophyta | No natural covering on seeds | Cycas |
Pteridophyta | These plants mainly grow in water Algae | Tamarind |
Gymnosperms | These plants need water for reproduction | Moss |
Angiosperms | Tissues are present for conduction of water and food | Algae |
Ans:
| ‘A’ | ‘B’ | ‘C’ |
|---|---|---|
Thallophyta | Seeds are formed in fruits | Fern |
Bryophyta | No natural covering on seeds | Cycas |
Pteridophyta | These plants mainly grow in water Algae | Tamarind |
Gymnosperms | These plants need water for reproduction | Moss |
Angiosperms | Tissues are present for conduction of water and food | Algae |
2. Complete the sentences by filling in the blanks and explain those statements.
(angiosperms, gymnosperms, spore, bryophyta, thallophyta, zygote)
a. ______ plants have soft and fibre-like body.
Ans: Thallophyta
Explanation: These plants grow mainly in water, i.e., fresh water as well as saline water. Therefore, they usually have a soft and fiber-like (filamentous) body.
b. ______ is called the ‘amphibian’ of the plant kingdom.
Ans: Bryophyta
Explanation: They grow in moist soil but need water for reproduction. Therefore they are called ‘amphibians of the plant kingdom’.
c. In pteridophytes, asexual reproduction occurs by ______ formation and sexual reproduction occurs by ______ formation.
Ans: Spore, zygote
Explanation: Pteridophyta plants show alteration of generation. One generation reproduces by spore formation, and the next generation reproduces sexually by zygote formation.
d. Male and female flowers of ______ are borne on different sporophylls of the same plant.
Ans: Gymnosperms
Explanation: As these plants do not require the assistance of pollinators, i.e., vectors, The male and female flowers must be present on different sporophylls of the same plant for successful fertilization.
3. Answer the following questions in your own words.
a. Write the characteristics of subkingdom Phanerogams.
Ans:
(i) Plants which have special structures for reproduction and produce seeds are called phanerogams.
(ii) In these plants, after the process of reproduction, seeds are formed which contain the embryo and stored food.
(iii) During germination of the seed, the stored food is used for the initial growth of the embryo.
(iv) Depending upon whether seeds are enclosed in a fruit or not phanerogams are classified into gymnosperms and angiosperms.
b. Distinguish between monocots and dicots.
Ans:
| Dicots | Monocots | |
|---|---|---|
Seed | Two cotyledons | Single cotyledon |
Root | Well- developed primary root (Tap root) | Fibrous roots |
Stem | Strong, hard. e.g., Banyan tree | Hollow. e.g., Bamboo. False. e.g., Banana Disc-like e.g., Onion |
Leaf | Reticulate venation | Parallel venation |
Flower | Flowers with 4 or 5 parts or in their multiples (tetramerous or pentamerous) | Flowers that have three parts or are multiples of three (trimerous) |
c. Write a paragraph in your own words about the ornamental plants called ferns.
Ans:
(i) Ferns belong to the group of plants called Pteridophyta.
(ii) They have well-developed roots, stems, and leaves, but they do not bear flowers or fruits.
(iii) They have separate tissues for food and water transportation.
(iv) They reproduce with the help of spores formed along the back or posterior surface of their leaves.
(v) They reproduce asexually by spore formation and sexually by zygote formation.
d. Sketch, label and describe the Spirogyra.
Ans:
(i) Spirogyra belongs to the division Thalophyta.
(ii) They are called algae. It grows mainly in water.
(iii) It does not have specific parts like roots, stems, leaves, or flowers but is autotrophic due to the presence of chlorophyll.
(iv) The plant body of Spirogyra is soft and fiber-like.
(v) It has spirally arranged chloroplasts in its cell.
e. Write the characteristics of the plants belonging to division Bryophyta.
Ans:
(i) The Bryophyta group of plants is called the amphibians of the plant kingdom because they grow in moist soil but need water for reproduction.
(ii) These plants are thalloid, multicellular, and autotrophic.
(iii) They reproduce by spore formation.
(iv) Their plant body structure is flat, ribbon-like, long, and without true roots, stems, or leaves.
(v) They have stem-like or leaf-like parts and root-like rhizoids.
(vi) They lack special tissues for food and water transport.
(vii) Examples: Moss (Funaria), Anthoceros, Riccia, etc.
4. Sketch and label the figures of the following plants and explain them into brief.
Marchantia and Funaria
Ans:
(i) These plants are called ‘amphibians’ in the plant kingdom because they grow mostly in soil and need water for reproduction.
(ii) They do not have specific tissues for the transmission of food and water.
(iii) The plant body is fiat, ribbon-like, and long, without true roots, stems, or leaves.
(iv) Instead, they have stem-like or leaf-like parts and roots like rhizoids.
Fern
Ans:
(i) They have well-developed roots, stems, and leaves for the transmission of food and water.
(ii) They do not bear flowers or fruits.
(iii) They reproduce with the help of spores present along the back or posterior surface of the leaves.
Spirogyra
Ans:
(i) Spirogyra belongs to the division Thalophyta.
(ii) They are called algae. It grows mainly in water.
(iii) It does not have specific parts like roots, stems, leaves, or flowers but is autotrophic due to the presence of chlorophyll.
(iv) The plant body of Spirogyra is soft and fiber-like.
(v) It has spirally arranged chloroplasts in its cell.
5. Collect a monocot and dicot plant available in your area. Observe the plants carefully and describe them in scientific language.
Ans:
Monocot Plant: Lily
(i) Its seeds cannot be divided into two equal halves.
(ii) Its roots are fibrous.
(iii) Its stem is hollow.
(iv) Its leaves show parallel venation.
(v) Flowers composed of three parts or in multiples of three (trimerous).
Dicot Plant: Hibiscus
(i) Its seeds can be divided into two equal halves.
(ii) It has well developed roots. There is a primary root (tap root) and many secondary roots arise from the primary roots.
(iii) Its stem is strong and hard.
(iv) Its leaves show reticulate venation.
(v) Its flowers have four to five petals (Pentamerous).
6. Which criteria are used for the classification of plants? Explain with reasons.
Ans:
(i) In the presence or absence of organs.
(ii) The presence or absence of separate conducting tissues for water and food conduction.
(iii) Whether the plants bear seeds or not.
(iv) If they bear seeds, whether the seeds are contained within a fruit or not.
(v) Number of cotyledons in the seeds.