1. Phylum Bryophyta Phylum Tracheophyta Jaime Crosby, CHS
Kingdom Plantae
Phylum Bryophyta
Phylum Tracheophyta
Jaime Crosby, CHS

2. The first plants were water plants (algae)
Adaptations necessary for life on land
The ability to acquire water
The ability to conserve water
The ability to transport water
The ability to reproduce without water

3. The first land plants…
Fossils didn’t tell us much as they had soft bodies, so they didn’t preserve well
500 to 600 mya
Phylum Bryophyta: Mosses, liverworts and hornworts
Phylum Tracheophyta: Ferns and higher plants

4. Difficult Adaptations to land
Requirements for life on land:
All cells need a constant supply of water, especially those exposed to dry air like stems
All plants must prevent water from escaping once it is obtained
Food making parts must have a support system that exposes them to the sunlight

5. Plants must be able to transport water up and food down the stem
Exchange water and CO2 without dessication
Reproduction in an environment that lacks standing water for the sperm to swim, and to prevent embryo from drying out

6. Have bryophytes adapted?
PARTIALLY! They live on land, but still need to remain moist.
Tracheophytes continued to evolve

7. Mosses, Liverworts and Hornworts
Exhibit alternation of generations between haploid gametophyte and diploid sporophyte stages
Gametophyte: dominant in mosses—the stage we SEE
Sporophyte: dependant diploid phase

8. Grow in swamps, near streams in rainforests and in other moist areas
Perform photosynthesis (green)
Only grow a few cm tall because they don’t have xylem and phloem!
Non-vascular

9. Structure of Bryophytes
Rhizoids (not roots!) branch into the ground to anchor plants
Mature gametophyte stage makes small umbrellas which release eggs and sperm

10. Liverworts: flat green leaves
Hornworts: flat green leaves with a sporophyte generation that looks like a tiny french horn

11. Differences from other, more advanced plants—this is what limits Bryophytes
Lack vascular tissue
Water passes from cell to cell by osmosis…thus mosses are short
Lack cuticle
Lose water very quickly
Lack true roots
Inefficient absorption and transport of water
Rhizoids anchor but do not absorb
Have sperm cells with flagella that have to swim to fertilize eggs

12. For these reasons, bryophytes must live in areas that are wet for at least part of the year. They can live in dry areas, but cannot grow while they are dry.

13. Alternation of Generations in mosses
Life Cycle: KNOW THIS!
Gametophyte stage
Antheridium-male reproductive structure; produces sperm cells
Archaegonium-female reproductive structure;produces egg cells
Both are designed to avoid dessication

14. Alternation of Generations
Sporophyte stage
A diploid capsule that emerges above moss plant (foot + stalk + capsule)
Inside, haploid spores are produced
Capsule opens, spores carried away
Spore lands in wet area, grows into PROTENEMA, which grows rhizoids and becomes the moss

15. Summary of Life Cycle Haploid gametophyte is dominant, obvious stage
Diploid sporophyte is DEPENDENT, because it requires energy from the gametophyte to occur
Some mosses are hermaphrodites, self or cross-fert.
Water must be present for sperm to swim and syngamy to occur