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Kingdom Classification - Classification of Plants (Thallophyta to Angiosperms)

Grade 7ICSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Kingdom Plantae consists of multicellular, eukaryotic organisms that are autotrophic, containing chlorophyll for photosynthesis: 6CO2+6H2O→sunlight/chlorophyllC6H12O6+6O26CO_{2} + 6H_{2}O \xrightarrow{sunlight/chlorophyll} C_{6}H_{12}O_{6} + 6O_{2}.

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Thallophyta: Plants with a body not differentiated into roots, stems, and leaves; the body is called a thallus. Example: SpirogyraSpirogyra.

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Bryophyta: Known as the 'Amphibians of the Plant Kingdom' because they live on land but need water for fertilization. They lack true vascular tissues (XylemXylem and PhloemPhloem).

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Pteridophyta: The first terrestrial plants to possess vascular tissues (XylemXylem and PhloemPhloem). They reproduce via spores rather than seeds. Example: Ferns.

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Gymnosperms: Plants that bear 'naked seeds' usually in structures called cones. Examples include PinusPinus and CycasCycas.

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Angiosperms: Flowering plants where seeds are enclosed within a fruit. They are the most highly evolved plants.

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Monocotyledons (Monocots): Angiosperms with a single cotyledon, parallel venation in leaves, and fibrous roots. Example: Zea maysZea \ mays (Maize).

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Dicotyledons (Dicots): Angiosperms with two cotyledons, reticulate (net-like) venation, and a taproot system. Example: Pisum sativumPisum \ sativum (Pea).

📐Formulae

6CO2+6H2O→SunlightC6H12O6+6O26CO_{2} + 6H_{2}O \xrightarrow{Sunlight} C_{6}H_{12}O_{6} + 6O_{2}

Kingdom→Division→Class→Order→Family→Genus→Species\text{Kingdom} \rightarrow \text{Division} \rightarrow \text{Class} \rightarrow \text{Order} \rightarrow \text{Family} \rightarrow \text{Genus} \rightarrow \text{Species}

💡Examples

Problem 1:

A plant has leaves with reticulate venation and the seeds can be split into two equal halves. Classify this plant within the Angiosperm group.

Solution:

The plant is a Dicotyledon (Dicot).

Explanation:

Plants with two cotyledons (seeds splitting into two halves) and reticulate venation (net-like pattern) are categorized as Dicots.

Problem 2:

Why is MarchantiaMarchantia (a Bryophyte) called an amphibian of the plant kingdom?

Solution:

Because it requires water for the process of sexual reproduction.

Explanation:

While Bryophytes like MarchantiaMarchantia live on damp soil, their sperm (antherozoids) must swim through a film of H2OH_{2}O to reach the egg for fertilization.

Problem 3:

Identify the group: A plant produces seeds but does not produce flowers or fruits. Its seeds are found on the scales of cones.

Solution:

Gymnosperms

Explanation:

Gymnosperms are characterized by 'naked seeds' (GymnosGymnos = naked, SpermaSperma = seed) that are not enclosed in a fruit, often borne on woody cones.

Classification of Plants (Thallophyta to Angiosperms) Revision - Class 7 Science ICSE