Ch 25 Seedless Plants

Transition to Land

• Green Algal Ancestry

  • Potential questions might ask about structural or reproductive similarities to charophytes (like the presence of a similar photosynthetic pigment set or zygote-protecting compounds).

• Land Challenges:

  • Desiccation, structural support, reproduction without water. Look out for questions about sporopollenin (protecting spores from drying), cuticles, stomata, mycorrhizae for nutrient uptake.

Bryophytes (Non-vascular Plants)

• Dominant Gametophyte

  • Typical exam focus: The gametophyte is free-living and photosynthetic, while the sporophyte is often smaller and dependent.

  • Water-Dependent Fertilization: Sperm are flagellated; you might see questions about “How does fertilization in a moss occur?” (They rely on water droplets for sperm to reach eggs in archegonia.)

Seedless Vascular Plants

• Ferns, Lycophytes, Horsetails

  • Sporophyte Dominant with vascular tissue.

  • You might see a question referencing coal forests of the Carboniferous and linking them to large vascular seedless plants with features like megaphylls (broad leaves) or tall growth.

  • Spore Dispersal: They do not have seeds or pollen. Fertilization is still reliant on water for sperm movement.

Which feature would you least likely find in the Carboniferous forest?” → Something like seeds, pollen, or fruit (all are seed-plant innovations).