1. Non-Vascular Plants

2. Evolution of Land Plants
Land plants evolved from green algae
The green algae called charophyceans are the closest relatives of land plants
Comparisons of both nuclear and chloroplast genes
Point to charophyceans as the closest living relatives of land plants
Chara,
a pond
organism
(a)
10 mm
Coleochaete orbicularis, a disk-
shaped charophycean (LM)
(b)
40 µm

3. Origin and Diversification of Plants
Fossil evidence indicates that plants were on land at least 475 million years ago
Whatever the age of the first land plants those ancestral species gave rise to a vast diversity of modern plants

4. Seedless vascular plants
Plant Evolution
Bryophytes
(nonvascular plants)
Seedless vascular plants
Seed plants
Vascular plants
Land plants
Origin of seed plants
(about 360 mya)
Origin of vascular
plants (about 420 mya)
Origin of land plants
(about 475 mya)
Ancestral
green alga
Charophyceans
Liverworts
Hornworts
Mosses
Lycophytes(club mosses, spike mosses, quillworts)
Pterophyte (ferns, horsetails, whisk fern)
Gymnosperms
Angiosperms

5. Bryophytes
Life cycles of mosses and other bryophytes are dominated by the gametophyte stage
Bryophytes are represented today by three phyla of small herbaceous (nonwoody) plants
Liverworts, phylum Hepatophyta
Hornworts, phylum Anthocerophyta
Mosses, phylum Bryophyta

6. Bryophytes Nonvascular (pass water cell-to-cell)
Seedless (reproduce by spores)
Low growing
Phylum Bryophyta (also includes liverworts & hornworts)
Grow on moist brick walls, in sidewalks, as thick mats on forest floors, and on the shaded side of trees

7. Bryophytes
Can survive periodic dry spells, reviving when water becomes available
Require water for fertilization so sperm can swim to egg
Rhizoids (root like structures) anchor mosses
Have waxy covering called cuticle on aerial parts to prevent desiccation

8. Gametophyte generation produces gametes (eggs & Sperm)
Dominant form of a moss is a clump of leafy green gametophytes  (photosynthetic)
 Moss alternates between a haploid (1n) gametophyte and diploid (2n) sporophyte
Gametophyte generation produces gametes (eggs & Sperm)
Sporophyte generation forms at the top of the gametophytes and produces spores 
Stalk-like sporophytes lack chlorophyll
Capsule at the top of the sporophyte forms haploid (1n) spores
 a Diploid (2n) sporophyte stage (contains two sets of chromosomes, one from male and one from female) and a
Haploid (1n) gametophyte stage (contains one set of chromosomes)
This type of life cycle is called Alternation of Generations

9. Sexual reproduction in Moss:
Moss produce 2 kinds of jacketed gametes --- eggs & sperm
Egg producing organ is called the archegonium
Eggs are larger and nonmotile
Sperm producing organ is called the antheridium
Sperm are smaller, flagellated cells
Antheridia & archegonia are both part of the gametophyte plant
Fertilization can occur only during or soon after RAIN  when the gametophyte is covered with Water
Sperm swim to the egg by following a trail of chemicals released by the egg in the water
Fertilization produces a zygote that becomes a sporophyte
Mature sporophytes produce homosporous spores (all the same type)
Mature capsules open & release spores spread by wind
Spores landing on moist places germinate into protonema that become new gametophytes

10. Only the zygote is 2n

11. Liverworts Have no true roots or shoots Non- vascular
Require water to reproduce
Have no or very little leaf structure
Cannot live in sporophyte form

12. Hornworts Free-floating aquatic plant, or land plant
No vascular tissue
No true leaves or roots
Can live in both gametophyte and sporophyte forms

13. Mosses Land plant Most have no vascular tissue
Majority of life spent in gametophyte stage
Need water to breed
No leaves or roots
Sporophytes are capsules on stalks