NEET Physics: Waves – NCERT Masterclass & 100 MCQ Quiz

PLANT KINGDOM

NCERT Masterclass & NEET Biology Study Module

1. Systems of Classification

• Artificial System: Based on gross superficial morphological characters (habit, color, shape of leaves). Given by Linnaeus (based on androecium structure). Separated closely related species.
• Natural System: Based on natural affinities among organisms, considering internal features like ultrastructure, anatomy, embryology, and phytochemistry. Given by George Bentham and Joseph Dalton Hooker.
• Phylogenetic System: Based on evolutionary relationships. Assumes organisms in the same taxa have a common ancestor.

Modern Taxonomy Branches:

• Numerical Taxonomy: Uses computers to assign numbers/codes to all observable characters.
• Cytotaxonomy: Based on cytological information like chromosome number, structure, and behavior.
• Chemotaxonomy: Uses the chemical constituents of the plants to resolve confusions.

2. Algae

Chlorophyll-bearing, simple, thalloid, autotrophic, and largely aquatic organisms. Reproduction can be vegetative (fragmentation), asexual (zoospores), or sexual (isogamous, anisogamous, oogamous).

3. Bryophytes (Amphibians of Plant Kingdom)

They live in soil but depend on water for sexual reproduction. Plant body is thallus-like, lacking true roots, stem, or leaves. The main plant body is haploid ($n$) and produces gametes (Gametophyte).

• Liverworts: Thalloid body (e.g., Marchantia). Asexual reproduction by fragmentation or Gemma cups (green, multicellular, asexual buds).
• Mosses: Gametophyte has two stages: Protonema stage (creeping, green, branched) and Leafy stage (upright, bears sex organs). E.g., Funaria, Sphagnum (provides peat, used as packing material).
• Sporophyte: Not free-living; attached to and dependent on the gametophyte for nourishment.

4. Pteridophytes (First Vascular Plants)

Used for medicinal purposes and as soil-binders. They are the first terrestrial plants to possess vascular tissues (xylem and phloem). The main plant body is a sporophyte ($2n$) differentiated into true roots, stem, and leaves.

Key Features:

• Spores germinate into a small, multicellular, free-living, photosynthetic gametophyte called Prothallus.
• Requires water for fertilization.
• Homosporous: Produce one kind of spores (Most pteridophytes).
• Heterosporous: Produce two kinds of spores (macro and micro). E.g., Selaginella and Salvinia. This event is a precursor to the Seed Habit.

5. Gymnosperms (Naked Seeds)

Ovules are not enclosed by any ovary wall and remain exposed, both before and after fertilization. The seeds are naked. Dominant phase is Sporophyte ($2n$).

• Roots: Generally tap roots. Pinus has fungal association (Mycorrhiza). Cycas has small specialized Coralloid roots containing $N_2$-fixing cyanobacteria.
• Stem: Unbranched (Cycas) or branched (Pinus, Cedrus).
• Always heterosporous. The male and female gametophytes do not have an independent free-living existence; they remain within the sporangia retained on the sporophyte.

6. Angiosperms and Alternation of Generations

Angiosperms are flowering plants where seeds are enclosed by fruits. They show unique Double Fertilization (Syngamy + Triple Fusion). Divided into Monocotyledons and Dicotyledons.

Patterns of Life Cycles:
1. Haplontic: Dominant phase is haploid gametophyte. Sporophyte is 1-celled zygote. (Volvox, Spirogyra, Chlamydomonas).
2. Diplontic: Dominant phase is diploid sporophyte. (Fucus, All Gymnosperms & Angiosperms).
3. Haplo-diplontic: Both phases are multicellular. (Bryophytes, Pteridophytes, Ectocarpus, Polysiphonia, Kelps).

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🚀 NEET PLANT KINGDOM MEGA QUIZ (100 MCQ)

Solve the 5 parts below to master Algae, Bryophytes, Gymnosperms, and Life Cycles.

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