Bihar Board - Class 11 biology - Chapter 3: Plant kingdom Handwritten Notes

The plant kingdom, also known as Kingdom Plantae, encompasses all multicellular, eukaryotic, and autotrophic organisms capable of photosynthesis. This chapter explores the classification of plants based on their structure, reproduction, and evolutionary development. It provides a comprehensive overview of the major groups, from simple algae to complex flowering plants.

Key Points

1. Characteristics of Kingdom Plantae

   • Eukaryotic, multicellular organisms with cell walls made of cellulose.
   • Contain chlorophyll and perform photosynthesis for energy.
   • Reproduce sexually or asexually (via spores or seeds).
   • Exhibit alternation of generations: sporophyte (diploid) and gametophyte (haploid) phases.

2. Classification of the Plant Kingdom
   Plants are classified into the following groups based on their evolutionary complexity:

   A. Algae

   • Simple, aquatic, photosynthetic organisms.
   • Examples: Green algae (Spirogyra), brown algae (Laminaria), and red algae (Gelidium).
   • Importance: Produce oxygen, form the base of aquatic food chains, and are used in industries (e.g., agar extraction).

   B. Bryophytes

   • Non-vascular plants that lack xylem and phloem.
   • Found in moist, shaded environments.
   • Examples: Mosses (Funaria) and liverworts (Marchantia).
   • Importance: Help in soil formation and prevent soil erosion.

   C. Pteridophytes

   • First vascular plants, with xylem and phloem but no seeds.
   • Reproduce through spores and thrive in moist habitats.
   • Examples: Ferns (Dryopteris) and horsetails (Equisetum).
   • Importance: Form part of the ecosystem and serve as ornamental plants.

   D. Gymnosperms

   • Seed-bearing plants with naked seeds (not enclosed in fruits).
   • Examples: Cycas, pine (Pinus), and deodar (Cedrus).
   • Importance: Source of timber, paper, and resins.

   E. Angiosperms

   • Flowering plants with seeds enclosed in fruits.
   • Subdivided into:
     • Monocots: One cotyledon (e.g., wheat, rice).
     • Dicots: Two cotyledons (e.g., mango, rose).
   • Importance: Provide food, medicine, and raw materials for various industries.

3. Alternation of Generations

   • Plants exhibit a life cycle alternating between two phases:
     • Sporophyte: The diploid phase that produces spores.
     • Gametophyte: The haploid phase that produces gametes.
   • This alternation ensures genetic diversity and adaptation.

4. Economic and Ecological Importance of Plants

   • Oxygen Production: Plants are the primary producers of oxygen through photosynthesis.
   • Food Source: Provide fruits, vegetables, grains, and other edible resources.
   • Medicinal Uses: Many plants are used in traditional and modern medicine.
   • Ecological Role: Maintain ecological balance by acting as primary producers in food chains.
   • Industrial Applications: Timber, paper, resins, and fibers are derived from plants.

Conclusion

The plant kingdom is diverse, ranging from simple algae to complex flowering plants. Understanding their classification helps us appreciate their evolutionary history, ecological roles, and contributions to human life. Plants are vital for maintaining life on Earth, making their study essential for sustainable development and conservation.

हिंदी के सभी अध्याय के महत्वपूर्ण प्रशन उत्तर के लिए अभी Download करें Vidyakul App - Free Download Click Here