plants - eukaryotic, multicellular, autotrophic
- alternation of generations (heteromorphic) - haploid >> diploid (haplodiplontic)
- humans have diplontic life cycles (only diploid form = multicellular)
- sporophyte - diploid, creates spores through meiosis
- gametophytes - haploid, creates gametes through mitosis
- adapted to terrestrial environment - cuticle (waxy covering), cork layers, bark prevent drying out
- gas exchange controlled by guard cells, stomata
- structural support - no more water to hold up the plant
- lignin - stiffening substance >> plant stays vertical
- guarantees maximum surface area for sunlight absorption
- phloem/xylem transport system evolves to replace intracellular transport
- 2 major plant groups - nonvascular, vascular
- nonvascular - 3/12 phyla, no tissue for water/nutrient transport
- vascular - xylem/phloem transport system
nonvascular plants - “bryophytes,” transition between aquatic algae and land plants
- less than 7cm tall
- no conducting vessels
- lack true roots, stems, leaves
- needs water for reproduction
- Bryophyta - moss
- anchored by rhizoid
- 1-cell thick
- gametophyte - small, leaf-like; archegonia (egg) and antheridia (sperm)
- Hepaticophyta - leafy/thallose liverworts
- grows prostrate (horizontal to ground)
- gametangia - umbrella structure for sexual reproduction
- gemmae for asexual reproduction
- Anthrocerophyta - hornworts
- sporophyte at top, attached to gametophyte
- sporophyte continues to grow, not just for reproduction
Subject:
Subject X2:
