Classification of Plants Chapter 2 (Class 7 - Concise Biology Selina) ICSE

 

Proposed Flowchart

flowchart for plant classification 

Key Points:

• The flowchart visually represents the classification process.
• Decision points are clearly indicated using diamonds.
• Arrows show the flow of classification.
• Each plant group is represented

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Classification of Plants Chapter 2

(Class 7 - Concise Biology Selina)

Multiple Choice Questions

Question 1

The two main categories of plants recognised on the basis of whether they produce fruits or not are:

1. Biennials and annuals
2. Angiosperms and gymnosperms
3. Herbs and shrubs
4. Bryophyta and pteridophyta

Answer

Angiosperms and gymnosperms

Reason — Angiosperm are flowering plants that produce fruits while gymnosperms produce only seeds without producing fruits.

Question 2

Unicellular organisms with a proper nucleus are included in the group:

1. Protista
2. Monera
3. Fungi
4. Algae

Answer

Protista

Reason — Kingdom Protista consists of unicellular organisms with a proper nucleus.

Question 3

Amoeba belongs to:

1. Monera
2. Protista
3. Fungi
4. Algae

Answer

Protista

Reason — A prominent nucleus is present in Amoeba.

Short Answer Questions

Question 1

Name the categories of the following:

1. Plants which do not have roots, stem, and leaves: ...............
2. Plants with no roots, but have stems and leaves: ................
3. Plants with roots, stems, and leaves, and which bear spore-producing bodies: ...............
4. The amphibians of the plant kingdom: ...............

Answer

Name the categories of the following:

1. Plants which do not have roots, stem, and leaves — Algae
2. Plants with no roots, but have stems and leaves — Bryophyta
3. Plants with roots, stems, and leaves, and which bear spore-producing bodies — Pteridophyta
4. The amphibians of the plant kingdom — Bryophyta

Question 2

Give two characteristics and one example for each of the following:

1. Algae
2. Fungi
3. Monocot
4. Dicot
5. Bryophyta
6. Pteridophyta
7. Gymnosperms

Answer

1. Two characteristics of Algae are:
1. They are aquatic in habitat.
2. They have chlorophyll and hence they are autotrophs.
   Example — Spirogyra
2. Two characteristics of Fungi are:
1. Body is composed of thread like structure called hyphae.
2. Chlorophyll is absent and they show heterotrophic nutrition.
   Example — Agaricus (Mushroom)
3. Two characteristics of Monocot are:
1. Seeds have a single cotyledon.
2. Leaves have parallel venation and roots are fibrous.
   Example — Maize
4. Two characteristics of Dicot are:
1. Seeds have two cotyledons.
2. Leaves with reticulate venation and roots show tap root system.
   Example — Pea
5. Two characteristics of Bryophyta are:
1. They have leaves and stems but no roots.
2. They have root like structure known as rhizoids.
   Example — Moss
6. Two characteristics of Pteridophyta are:
1. They have well formed leaves, stems and roots.
2. They do not produce flowers and seeds.
   Example — Fern
7. Two characteristics of Gymnosperm are:
1. Flowers and fruits are absent.
2. Bear naked seeds which are not enclosed in a fruit.
   Example — Pine

Question 3

(i) Differentiate between Algae and fungi.

Answer

Sl. No.	Algae	Fungi
1.	Chlorophyll is present.	Chlorophyll is absent.
2.	Are mostly aquatic, found in fresh as well as marine water.	Are mostly terrestrial.
3.	Photosynthetic organisms synthesizing their own food.	They are heterotrophs, usually live on dead and decaying organic matter and are called saprotrophs.
4.	Body not differentiated into root, stem and leaves,and is known as thallus.	Body is composed of thread-like structures called hyphae, and is known as mycelium.
5.	Examples: Spirogyra, Ulothrix	Examples: Agaricus, Penicillium

(ii) Differentiate between Monocot and dicot plants.

Answer

Sl. No.	Monocots	Dicots
1.	Seeds have a single cotyledon.	Seeds have two cotyledons.
2.	Leaves have parallel venation.	Leaves have reticulate venation.
3.	Fibrous root system is present.	Tap root system is present.
4.	Stem usually hallow.	Stem mostly solid.
5.	Example: Rice, grass	Example: Pea, Rose

 (iii) Differentiate between Autotrophs and heterotrophs

Answer

Sl. No.	Autotrophs	Heterotrophs
1.	The organisms which synthesize their own food are known as Autotrophs.	The organisms which cannot synthesize their own food are known as Heterotrophs.
2.	They synthesize their food by Photosynthesis or chemosynthesis.	They derive their nutrition from autotrophs.
3.	Example: Plants, Algae	Example: Animals, Fungi

(iv) Differentiate between Bacteria and Amoeba

Answer

Sl. No.	Bacteria	Amoeba
1.	Bacteria are classified under Monera kingdom.	Amoeba are classified under Protista kingdom.
2.	Prominent nucleus is absent, hence they are Prokaryotes.	Nucleus is present, hence they are Eukaryotes.

(v) Differentiate between Mosses and Ferns

Answer

Sl. No.	Mosses	Ferns
1.	They are called Bryophyta.	They are called Pteridophyta.
2.	They have stem and leaves, but no roots.	Well-formed leaves, stems and roots are found.
3.	They need water for reproduction.	They reproduce by producing spores in small bodies situated on the undersurface of leaves.

 (vi) Differentiate between Angiosperm and Gymnosperm

Answer

Sl. No.	Angiosperm	Gymnosperm
1.	Can be herbs, shrubs and trees.	Are mostly woody trees.
2.	Flowers and fruits are present.	Flowers and fruits are absent.
3.	Bear seeds enclosed in a fruit.	Bear naked seeds which are not enclosed in a fruit.
4.	Reproductive structures are unisexual or bisexual flowers.	Reproductive structures are unisexual cones (male or female) that bear the seeds.
5.	Example: Sugarcane, Mango	Example: Pine, cedar

Question 4

Match the items given under column I with those given under column II:

Sl. No.	Column I	Column II
1.	Bread mould	Has chlorophyll
2.	Spirogyra	Leaves with spores
3.	Moss	Naked seeds
4.	Fern	Saprophytes
5.	Gymnosperm	Has rhizoids

Answer

Sl. No.	Column I	Column II
1.	Bread mould	Saprophytes
2.	Spirogyra	Has chlorophyll
3.	Moss	Has rhizoids
4.	Fern	Leaves with spores
5.	Gymnosperm	Naked seeds

Long Answer Questions

Question 1

What name is given to the bacteria found in the root nodules of Pea plant? State their importance.

Answer

The bacteria found in the root nodules of Pea plant is Rhizobium. These bacteria are found in the root nodules of most of the leguminous plants. They trap the nitrogen from the atmosphere and convert it into nitrates (mineral salts) which can be easily absorbed by the plants from the soil along with the water. The Rhizobium bacteria lives in symbiotic relationship with the leguminous plants as the plant provides shelter to the bacteria and the bacteria provides nitrogen to the plant.

Question 2

Briefly explain four types of bacteria on the basis of their shape.

Answer

Four types of bacteria on the basis of their shape are:

1. Coccus — These are spherical or ovoid in shape.
2. Bacillus — These are rod-shaped. They may occur singly or in groups of two or three,              
                       joined end to end in long chains.
3. Spirillum — These are spiral-shaped bacteria.
4. Vibrio — These are comma-shaped bacteria. For example, Vibrio cholerae.

Question 3

(i) Give reasons for the following:

Bryophytes are called amphibians of the plant kingdom.

Answer

The Bryophytes are found on damp surfaces in moist places. They are called amphibians of the plant kingdom because they need water to reproduce. Like amphibians they need water as well as land to complete their life-cycle.

 (ii) Give reasons for the following:

Amoeba does not have any regular shape.

Answer

Amoeba has cell membrane as the outer covering of body. The cell membrane is a flexible structure which enables Amoeba to change its shape. Also, the Amoeba moves by extending the cytoplasm along the cell membrane, forming a finger-like structure known as Pseudopodia.

Question 4

What is a contractile vacuole? State its function in Amoeba.

Answer

The contractile vacuole in amoebas plays a crucial role in excretion by collecting excess water from the organism's body. This vacuole helps expel waste, primarily ammonia, which dissolves in water and is removed through the amoeba's general body surface via simple diffusion.

Question 5

List out five uses each of bacteria and fungi in our lives.

Answer

Five uses of Bacteria are:

• Bacteria are utilized in the production of antibiotic medicines, such as Streptomycin.
• Lactobacillus bacteria are employed for curdling milk to produce dairy products like yogurt.
• Acetobacter bacteria are used to convert fruit juices into vinegar.
• Bacteria play a role in the tanning of leather and the retting of jute.
• Bacteria facilitate the decay of organic materials, resulting in the formation of manures and composts.

Five uses of Fungi:

·  Source of Food: Fungi such as Agaricus (mushrooms) and Morchella (morels) are important food sources.

·  Yeast in Baking and Brewing: Yeast is essential in the baking industry and breweries for making bread and alcohol.

·  Decomposers: Fungi are excellent decomposers, breaking down organic matter and returning nutrients to the soil.

·  Penicillin Production: Penicillium notatum is used to produce penicillin, a vital antibiotic.

·  Cheese Ripening: Certain species of Mucor and Penicillium are used in the ripening of cheese, enhancing its flavor and texture.

Question 6

"Bacteria are harmful to human beings." Briefly explain this statement..

Answer

Bacteria are the culprits behind many diseases, including typhoid, leprosy, tuberculosis (TB), pneumonia, and cholera. They also cause the spoilage of various food items such as milk, meat, fish, and vegetables. Even tinned and packaged foods can spoil due to bacteria after their expiry date. Therefore, it's evident that bacteria can be harmful to human beings.

Question 7

With reference to number of seeds, venation in the leaves and type of roots, differentiate between monocotyledonous and dicotyledonous plants.

Answer

Sl. No.	Monocotyledonous Plant	Dicotyledonous Plant
1.	Seeds have a single cotyledon.	Seeds have two cotyledon.
2.	Leaves have parallel venation.	Leaves have reticulate venation.
3.	Fibrous root system is present.	Tap root system is present.
4.	Example: Rice, Grass	Example: Pea, Rose

Question 8

Briefly describe the binary fission in Amoeba.

Answer

Binary fission is the process by which amoebas reproduce, where a fully grown amoeba splits into two. Initially, the nucleus divides into two separate nuclei, followed by the division of the rest of the cell. This ensures that each new amoeba receives one daughter nucleus.

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