Kingdom Plantae
Can you recall? Page 19
1. Why do we call plants as producers on land?
Answer: Plants are called producers on land because they perform photosynthesis, using sunlight, water, and carbon dioxide to produce their own food (glucose) and oxygen. This makes them autotrophic, forming the base of the food chain by providing energy and nutrients for other organisms.
2. What are differences between sub-kingdoms Cryptogamae and Phanerogamae?
Answer:
- Cryptogamae: These are spore-producing plants that do not produce seeds or flowers. Their reproductive structures (sex organs) are concealed (kryptos: hidden, gamos: marriage). They include Thallophyta, Bryophyta, and Pteridophyta.
- Phanerogamae: These are seed-producing plants with visible reproductive structures (phaneros: visible). They include Gymnospermae and Angiospermae, which produce seeds, either naked (Gymnosperms) or enclosed within fruits (Angiosperms).
3. Differentiate between Thallophytes and Bryophytes.
Answer:
Thallophytes:
- Plant body is thalloid, undifferentiated into root, stem, and leaves.
- Mostly aquatic, some are epiphytic or symbiotic.
- Lack vascular tissues.
- Reproduction by vegetative, asexual, and sexual means; alternation of generations with dominant haploid phase.
- Examples: Chlorella, Spirogyra.
Bryophytes:
- Plant body is thalloid or leafy, with root-like structures called rhizoids.
- Mostly terrestrial, found in moist shady places, requiring water for fertilization (amphibious plants).
- Lack vascular tissues.
- Life cycle shows sporophytic and gametophytic stages, with dominant gametophyte.
- Examples: Riccia, Funaria.
4. Give any two examples of Pteridophyta.
Answer:
- Nephrolepis (Fern)
- Selaginella
Internet my friend Page 20
1. Make a list of green algae with their characteristic shape of chloroplast.
Answer: Green algae (Chlorophyceae) have chloroplasts of various shapes. Based on the information provided:
- Chlamydomonas: Chloroplast is cup-shaped.
- Spirogyra: Chloroplast is ribbon-shaped or spiral.
- Chara: Chloroplast shape is not specified in detail, but it is implied to be variable, likely discoid or plate-like in some cases.
- Volvox: Chloroplast is plate-like (in colonial forms).
- Ulothrix: Chloroplast is band-shaped or girdle-shaped.
2. Enlist the forms of filamentous algae.
Answer: Filamentous algae include:
- Unbranched filamentous: Spirogyra.
- Branched filamentous: Chara.
- Simple branched filamentous (in Phaeophyceae): Ectocarpus.
- Profusely branched (in Phaeophyceae): Petalonia.
3. Write different pigments found in algae.
Answer: Pigments found in algae:
- Chlorophyceae (Green algae): Chlorophyll a, Chlorophyll b.
- Phaeophyceae (Brown algae): Chlorophyll a, Chlorophyll c, Fucoxanthin.
- Rhodophyceae (Red algae): Chlorophyll a, Chlorophyll d, Phycoerythrin.
- General pigments across algae: Chlorophyll, Xanthophylls, Phycobilins (including Phycoerythrin in red algae).
Internet my friend Page 21
1. Economic importance of algae.
Answer:
- Food Source: Algae like Chlorella are rich in protein and used as food, even by space travelers.
- Hydrocolloids Production: Brown algae (e.g., Laminaria, Sargassum) are used to produce hydrocolloids like algin.
- Agar Production: Red algae (e.g., Gelidium, Gracillaria) are used to produce agar-agar, a solidifying agent in tissue culture medium.
- Marine Food: Many species of brown algae (e.g., Laminaria, Sargassum) are used as food in marine regions.
2. Role of algae in environment.
Answer:
- Oxygen Production: Algae contribute to oxygen production through photosynthesis, supporting aquatic ecosystems.
- Primary Producers: They form the base of the aquatic food chain, providing energy for other organisms.
- Nutrient Cycling: Algae help in nutrient cycling by absorbing and recycling nutrients in aquatic environments.
- Habitat Formation: Large algae like Sargassum provide habitats for marine organisms.
3. Different forms of green, red, brown, and blue-green algae.
Answer:
Green Algae (Chlorophyceae):
- Unicellular: Chlorella, Chlamydomonas.
- Colonial: Volvox.
- Filamentous: Spirogyra (unbranched), Chara (branched).
Red Algae (Rhodophyceae):
- Thalloid: Chondrus, Batrachospermum, Porphyra, Gelidium, Gracillaria, Polysiphonia.
Brown Algae (Phaeophyceae):
- Simple branched/Filamentous: Ectocarpus.
- Profusely branched: Petalonia.
- Macroscopic with holdfast, stipe, and frond: Laminaria, Sargassum, Fucus.
Can you tell? Page 21
1. What are the three major groups of Cryptogams?
Answer: The three major groups of Cryptogams are:
- Thallophyta
- Bryophyta
- Pteridophyta
2. Name the accessory pigments of algae.
Answer: The accessory pigments of algae include:
- Xanthophylls
- Phycobilins (e.g., Phycoerythrin in Rhodophyceae)
- Fucoxanthin (in Phaeophyceae)
3. Give salient features of algae.
Answer:
- Habitat: Mostly aquatic, some epiphytic, symbiotic, or epizoic.
- Plant Body: Thalloid, undifferentiated into root, stem, and leaves; can be unicellular (e.g., Chlorella), colonial (e.g., Volvox), or filamentous (e.g., Spirogyra).
- Cell Wall: Contains polysaccharides like cellulose, glucose, proteins, or both.
- Reserve Food: Stored as starch or its derivatives (e.g., Floridean starch in red algae).
- Pigments: Contain chlorophyll, xanthophylls, and phycobilins for photosynthesis.
- Reproduction: Vegetative, asexual, and sexual methods; exhibits alternation of generations with dominant haploid phase in most cases.
- Classification: Based on pigments (e.g., Chlorophyceae, Phaeophyceae, Rhodophyceae).
4. Differentiate between Chlorophyceae and Phaeophyceae.
Answer:
| Feature | Chlorophyceae (Green Algae) | Phaeophyceae (Brown Algae) |
|---|---|---|
| Habitat | Mostly freshwater, some brackish or marine. | Mostly marine, rarely freshwater. |
| Plant Body | Unicellular, colonial, or filamentous (e.g., Spirogyra). | Simple branched (e.g., Ectocarpus) or profusely branched (e.g., Petalonia). |
| Cell Wall | Contains cellulose. | Contains cellulose, fucans, and algin. |
| Pigments | Chlorophyll a, b. | Chlorophyll a, c, fucoxanthin. |
| Stored Food | True starch. | Mannitol, laminarin, starch. |
| Structure | No differentiation into holdfast, stipe, frond. | Differentiated into holdfast, stipe, and frond. |
| Examples | Chlamydomonas, Spirogyra, Chara, Volvox, Ulothrix. | Ectocarpus, Laminaria, Sargassum, Fucus. |
5. Enlist examples of Chlorophyceae and Rhodophyceae.
Answer:
- Chlorophyceae: Chlamydomonas, Spirogyra, Chara, Volvox, Ulothrix.
- Rhodophyceae: Chondrus, Batrachospermum, Porphyra, Gelidium, Gracillaria, Polysiphonia.
Can you tell? Page 23
1. Distinguish between Bryophyta and Pteriophyta.
Answer:
| Feature | Bryophyta | Pteridophyta |
|---|---|---|
| Plant Body | Thalloid or leafy, with root-like rhizoids; gametophyte dominant. | Differentiated into true roots, stem, and leaves; sporophyte dominant. |
| Vascular Tissues | Absent; non-vascular. | Present; vascular (xylem with tracheids, phloem with sieve cells). |
| Habitat | Mostly terrestrial, in moist shady places; require water for fertilization. | Moist and shady places, some aquatic or xerophytic; true land plants. |
| Reproductive Structures | Gametophyte bears sex organs; sporophyte short-lived, dependent. | Sporophyte bears sporangia; gametophyte independent, short-lived. |
| Life Cycle | Dominant haploid gametophyte; sporophyte partially or fully dependent. | Dominant diploid sporophyte; independent, autotrophic gametophyte. |
| Examples | Riccia, Funaria, Marchantia. | Nephrolepis, Selaginella, Equisetum. |
2. Why Bryophyta are called amphibians of Plant Kingdom?
Answer: Bryophytes are called amphibians of the Plant Kingdom because they are primarily terrestrial plants that grow in moist, shady environments but require water for fertilization and to complete their life cycle. Their dependence on water for the sperm to swim to the egg mirrors the amphibious nature of animals that live on land but need water for reproduction.
3. Pteridophytes are also known as vascular Cryptogams – Justify.
Answer: Pteridophytes are known as vascular Cryptogams because they possess vascular tissues (xylem and phloem), making them true land plants, but they are still Cryptogams as they reproduce via spores and do not produce seeds or flowers. Their concealed reproductive structures (gametes in gametangia) align with the Cryptogamae characteristic, while their vascular system distinguishes them from non-vascular Cryptogams like Bryophytes.
4. Give one example of aquatic and xerophytic Pteridophytes.
Answer:
- Aquatic Pteridophyte: Azolla.
- Xerophytic Pteridophyte: Equisetum.
Can you recall? Page 24
1. What are the salient features of Angiospermae?
Answer:
- Most advanced flowering plants with seeds enclosed in fruits (ovary).
- Highly evolved, primarily terrestrial.
- Sporophyte dominant, diploid, autotrophic; gametophytes reduced, parasitic.
- Heterosporous with microspores (pollen) in stamens and megaspores in ovules (carpel).
- Flowers with essential (androecium, gynoecium) and accessory (calyx, corolla) whorls.
2. What is double fertilization ?
Answer: Double fertilization is the process in Angiosperms where one sperm fertilizes the egg to form a zygote (2n), and another sperm fuses with two polar nuclei to form a triploid endosperm, providing nourishment to the embryo.
3. Explain in brief two classes of Angiospermae? Draw and label one example of each class.
Answer:
- Dicotyledonae: Two cotyledons in embryo, tap root system, branched stem, reticulate leaf venation, tetra- or pentamerous flowers, vascular bundles open with cambium for secondary growth. Example: Helianthus annuus (Sunflower).
- Monocotyledonae: Single cotyledon, adventitious root system, rarely branched stem, parallel leaf venation, trimerous flowers, closed vascular bundles, secondary growth usually absent. Example: Zea mays (Maize).
Labeled Diagrams :
- Helianthus annuus (Sunflower): Label inflorescence (ray and disc florets), stem, tap root, seeds.
- Zea mays (Maize): Label tassel, silks, ear, corn grain, leaf blade, roots.
Can you tell? Page 25
1. Give general chara cters of Gymnospermae and Angiospermae.
Answer:
- Gymnospermae: Evergreen shrubs/trees, produce naked seeds, vascular with xylem (tracheids) and phloem (sieve cells), sporophyte dominant, tap root system, secondary growth present, dimorphic leaves (foliage and scale).
- Angiospermae: Advanced flowering plants, seeds enclosed in fruits, vascular, sporophyte dominant, heterosporous, flowers with essential (androecium, gynoecium) and accessory (calyx, corolla) whorls, double fertilization.
2. Distinguish between Dicotyledonae and Monocotyledonae.
Answer:
| Feature | Dicotyledonae | Monocotyledonae |
|---|---|---|
| Cotyledons | Two | One |
| Root System | Tap root | Adventitious |
| Stem | Branched | Rarely branched |
| Leaf Venation | Reticulate | Parallel |
| Flower Symmetry | Tetra- or pentamerous | Trimerous |
| Vascular Bundles | Open, with cambium | Closed, no cambium |
| Secondary Growth | Common | Usually absent |
3. Why do Dicots show secondary growth while Monocots don’t?
Answer: Dicots have vascular bundles with cambium, enabling secondary growth (thickening of stem/root). Monocots lack cambium in their closed vascular bundles, preventing secondary growth.
Can you tell? Page 26
1. What is alternation of generations?
Answer: Alternation of generations is the life cycle of plants where two distinct phases alternate: the diploid sporophyte (2n) produces haploid spores by meiosis, which develop into the haploid gametophyte (n). The gametophyte produces gametes that fuse during fertilization to form a diploid zygote, which grows into a sporophyte.
2. Which phase is dominant in the life cycle of Bryophyta and Pteridophyta?
Answer:
- Bryophyta: The haploid gametophyte phase is dominant, photosynthetic, and independent, while the sporophyte is short-lived and partially or fully dependent.
- Pteridophyta: The diploid sporophyte phase is dominant, independent, and vascular, while the haploid gametophyte is short-lived and autotrophic.
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