Plant Evolution â From Water to Land
Plants evolved from green algae â adapted to land â developed vascular system & seeds
Three major stages we study:
- Algae â Aquatic pioneers
- Bryophyta â First land colonizers
- Tracheophyta â True land conquerors
Side-by-Side Comparison
| Feature | Algae | Bryophyta | Tracheophyta |
|---|---|---|---|
| Habitat | Mainly aquatic | Moist terrestrial | Almost all terrestrial |
| Body structure | Thallus (undifferentiated) | Leaf-like, stem-like | True roots, stems, leaves |
| Vascular tissue | Absent | Absent | Present (xylem & phloem) |
| Dominant phase | Gametophyte | Gametophyte | Sporophyte |
| Size | Mostly microscopic to small | Small (cm) | From small to very tall trees |
| Water for reproduction | Needed | Needed (sperm swims) | Not always (pollen in seed plants) |
3. Algae (Thallophyta)
Simplest plant group â still live like their ancient aquatic ancestors
- Thallus body
- No vascular tissue
- Reproduction simple
- Ecological role
ðŽ Algae Microscope Lab
Explore the microscopic world of algae! Prepare your slide and observe different algae species.
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4. Bryophyta
First successful land plants â still very dependent on water
- Rhizoids
- Small plants
- Gametophyte dominant
- Water-dependent reproduction
ðŽ Bryophyta Microscope Lab
Examine moss structures under the microscope. Observe rhizoids, leaves, and reproductive structures.
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5. Tracheophyta (Vascular Plants)
The great breakthrough: vascular tissue allowed plants to grow tall!
- Vascular tissue
- Real roots
- Dominant phase changed
- Very diverse group
ðŽ Tracheophyta Microscope Lab
Study vascular tissues in detail. Observe xylem, phloem, and other specialized plant structures.
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