Plant Kingdom – Class 11 Biology Notes
Introduction to the Plant Kingdom
The Plant Kingdom includes a vast variety of organisms, from simple plants like algae to complex plants such as flowering plants. The plants are autotrophic organisms, meaning they produce their own food through photosynthesis. They have important roles in nature, including oxygen production, food for animals, and maintaining ecological balance.
Classification of the Plant Kingdom
The Plant Kingdom is classified into the following major groups:
- Thallophyta (Algae)
- Bryophyta (Mosses and Liverworts)
- Pteridophyta (Ferns)
- Gymnosperms (Cone-bearing Plants)
- Angiosperms (Flowering Plants)
Each of these groups has specific characteristics that differentiate them from one another.
1. Thallophyta (Algae)
Key Characteristics:
- Body Organization: Simple, undifferentiated body (thallus)
- Nutrition: Autotrophic (photosynthesis), some can also be heterotrophic
- Habitat: Aquatic, both freshwater and marine
- Reproduction: Both sexual and asexual
Types of Algae:
- Green Algae (e.g., Chlorella, Spirogyra)
- Brown Algae (e.g., Fucus, Sargassum)
- Red Algae (e.g., Porphyra, Polysiphonia)
2. Bryophyta (Mosses and Liverworts)
Key Characteristics:
- Body Organization: Simple, multicellular (leafy, non-vascular)
- Vascular Tissue: Absent (no xylem and phloem)
- Reproduction: Both sexual (by gametes) and asexual (by spores)
- Habitat: Moist, terrestrial environments
- Water Requirement: Required for fertilization
Examples:
- Mosses (e.g., Funaria, Sphagnum)
- Liverworts (e.g., Marchantia, Riccia)
3. Pteridophyta (Ferns)
Key Characteristics:
- Body Organization: Vascular, well-differentiated body (roots, stems, leaves)
- Vascular Tissue: Present (xylem and phloem)
- Reproduction: Sexual (by spores), no seeds
- Habitat: Mostly terrestrial, some grow in moist, shady places
- Water Requirement: Required for fertilization
Examples:
- Ferns (e.g., Dryopteris, Pteris)
- Club Mosses (e.g., Lycopodium)
- Horse tails (e.g., Equisetum)
4. Gymnosperms (Cone-bearing Plants)
Key Characteristics:
- Body Organization: Well-differentiated plant body (roots, stems, leaves)
- Vascular Tissue: Present (xylem and phloem)
- Reproduction: Sexual (by seeds), but seeds are not enclosed in a fruit (naked seeds)
- Pollination: By wind (no flowers)
- Leaves: Needle-like or scale-like
Examples:
- Conifers (e.g., Pine, Cedar, Fir)
- Cycads (e.g., Cycas)
- Ginkgo (e.g., Ginkgo biloba)
5. Angiosperms (Flowering Plants)
Key Characteristics:
- Body Organization: Well-differentiated plant body (roots, stems, leaves, flowers)
- Vascular Tissue: Present (xylem and phloem)
- Reproduction: Sexual (by seeds enclosed in fruits)
- Pollination: Can be biotic (by insects, birds, etc.) or abiotic (by wind or water)
Types of Angiosperms:
- Monocots (e.g., Grasses, Lilies)
- One cotyledon
- Parallel venation
- Flower parts in multiples of 3
- Dicots (e.g., Rose, Sunflower)
- Two cotyledons
- Reticulate venation
- Flower parts in multiples of 4 or 5
Key Differences Between the Plant Groups
| Characteristic | Thallophyta (Algae) | Bryophyta (Mosses) | Pteridophyta (Ferns) | Gymnosperms (Cone-Bearing) | Angiosperms (Flowering Plants) |
|---|---|---|---|---|---|
| Vascular Tissue | Absent | Absent | Present | Present | Present |
| Reproduction | Asexual & Sexual | Sexual & Asexual | Sexual (Spores) | Sexual (Naked Seeds) | Sexual (Seeds in Fruits) |
| Fertilization | Requires water | Requires water | Requires water | Wind pollinated | Biotic or Abiotic Pollination |
| Examples | Green, Brown, Red Algae | Mosses, Liverworts | Ferns, Horse tails | Pine, Cycas, Ginkgo | Roses, Sunflowers, Mango |
MCQs – Plant Kingdom
1. The plant kingdom is classified into how many main groups?
a) 3
b) 4
c) 5
d) 6
Answer: c) 5
2. Which of the following is a characteristic of Bryophytes?
a) Vascular tissues present
b) Seeds present
c) Fertilization requires water
d) Pollinated by wind
Answer: c) Fertilization requires water
3. Gymnosperms are different from angiosperms because:
a) Gymnosperms have seeds enclosed in fruits, while angiosperms do not
b) Gymnosperms have non-enclosed seeds, while angiosperms have seeds in fruits
c) Gymnosperms are non-flowering, while angiosperms are flowering
d) Both b and c
Answer: d) Both b and c
4. Which of the following plants are non-vascular?
a) Ferns
b) Gymnosperms
c) Mosses
d) Angiosperms
Answer: c) Mosses
5. In which group of plants are the seeds enclosed within the fruit?
a) Gymnosperms
b) Angiosperms
c) Pteridophytes
d) Bryophytes
Answer: b) Angiosperms
6. Which of the following is a characteristic feature of dicots?
a) Parallel venation
b) Single cotyledon
c) Flower parts in multiples of 4 or 5
d) Fibrous root system
Answer: c) Flower parts in multiples of 4 or 5
7. Which of the following is an example of a fern?
a) Cycas
b) Sphagnum
c) Pteris
d) Sunflower
Answer: c) Pteris
8. The largest group of plants is:
a) Bryophytes
b) Gymnosperms
c) Angiosperms
d) Pteridophytes
Answer: c) Angiosperms
9. Algae are primarily classified into which plant group?
a) Bryophyta
b) Thallophyta
c) Pteridophyta
d) Gymnosperms
Answer: b) Thallophyta
10. In Gymnosperms, the seeds are exposed in:
a) Fruits
b) Cones
c) Flowers
d) Leaves
Answer: b) Cones