Plant Kingdom
The Plant Kingdom is diverse and comprises five major groups: algae, bryophytes, pteridophytes, gymnosperms, and angiosperms. Each group showcases unique features and adaptations that allow them to thrive in various environments.
- Algae: Simple, thalloid, autotrophic organisms primarily aquatic, responsible for significant carbon dioxide fixation and oxygen production. Algae are classified into three major groups based on pigment and food storage - Chlorophyceae (green algae), Phaeophyceae (brown algae), and Rhodophyceae (red algae).
- Bryophytes: Known as the amphibians of the plant kingdom, they thrive in moist conditions and are characterized by a gametophyte dominant life cycle. Key reproductive structures include antheridia for male gametes and archegonia for female gametes.
- Pteridophytes: The first vascular plants, consisting of ferns and horsetails, with a dominant sporophyte generation. They reproduce via spores and require moisture for fertilization.
- Gymnosperms: These seed-producing plants have exposed seeds not enclosed by an ovary, and they include coniferous trees like pines and spruces. They are characterized by male and female cones.
- Angiosperms: Flowering plants that produce seeds enclosed in fruits, representing the largest group in the Plant Kingdom. They include a wide variety of sizes and forms divided into monocotyledons and dicotyledons.
This chapter underlines the evolution, classification, and ecological roles of these plant groups.