1. Lecture Ch. 29 Date _______
Plant Diversity I: The Colonization of Land

2. Plant Evolution
bryophytes (mosses), pteridophytes (ferns), gymnosperms (pines and conifers); angiosperms (flowering plants)
Plants: multicellular, eukaryotic, photosynthetic autotrophs
Terrestrial colonization:
Vascular tissue
The seed
The flower
Nonvascular plants -Bryophytes
Bryophytes differ from algae-have multicellular embryo attached to and nourished by parent plant.
Vascular plants-have xylem and phloem
Pteriodophtes-ferns called seedless plants-lack a seed stage

3. Nonvascular vs. Vascular plants
Nonvascular-Bryophytes
Vascular
Pteridophytes
Gymnosperms
Angiosperms

4. Plant origins Charophytes: green algae (closest plant ancestor)
Similarities:
1-Homologous chloroplasts: chlorophyll a & b
2- Biochemical similarity cellulose composition; peroxisomes
3- Cell division similarity mitosis; cytokinesis
4- Sperm similarity ultrastructure
5- Genetic relationship nuclear genes; rRNA
Cellulose in cell walls found in many algae groups including dinoflagellates and brown algae
Chlorophyll a and b found in euglenoids and some dinoflagellates.
Only charophyte algae and land plants have the same enzyme in peroxisomes -function antiphotorespiration
Cell division similarity in cell plate formation-phragmoplast which is an alignment of cyoskeletal elements and Golgi derived vesicles across the midline of the dividing cell.

5. Characteristics that separate plants from algae ancestors
Apical meristems: localized regions of cell division
Multicellular, dependent embryos (embryophytes)
Alternation of generations
Walled spores produced in sporangia
Multicellular gametangia
Apical meristem-localized regions of cell division at tips of shoots and roots.
Multicellular plant embryos develop from zygotes retained within tissue of female parents.
Parent provides nutrients for embryo uses placental transfer cells- analogous to mother -embryo (placental) in mammals.
Embryophytes- land plants
Sporangia are multicellular organs found on the sporophyte generation that produces the spores.
Spore mother cell w/in sporangia goes through meiosis to make spores.
Sporangia holds the spores until they are ready to be released.
Multicellular gametangia- produces the gametes. Gametangia is found in the gametophyte body.
Archegonia-female gametangia is vase-shaped organ that produces a single egg cell and retains the egg in base of organ.
Antheridia-mlae gametangia produces the sperm.

6. Other terrestrial adaptations
Cuticle
Stomata
Xylem and phloem
Secondary compounds
Adaptions for Water conservation-- cuticle and stomata
Adaptions for water transport --xylem and phloem
Secondary compounds-alkaloids, terpenes, tannins-have bitter tastes, strong odors or toxic effects
Defend plants against herbivores
Flavonoids absorb harmful UV radiation
flavonoids

7. Bryophytes Mosses, liverworts, and hornworts
1st to exhibit the embryonic condition (male = antheridium; female = archegonium)
Flagellated (water) sperm
No vascular tissue (imbibe water)
No lignin (short stature)
Haploid gametophyte is the dominant generation

8. Protonema-mass of green filaments that develop from germinating spores.
Rhizoids-root like structures
Sporophytes remain attached to gametophyte body
Usually photosynthetic when young.
Depend on the parent gametophyte for nutrition. Transferred by placental nutritive cells

9. Mosses

10. Parts of a Moss Plant
Sporangium-or capsule holds the spores on sporophyte body
Seta- stalk or stem of sporophyte body
Foot- obtains nutrients from gameotphyte body
Calyptra- protective covering over immature capsule
Peristome- upper part of capsule specialized for gradual spore
Protonema-mass of green filaments that grow from germinating spore.
Rhizoids-act as roots to anchor the gametophyte body.

11. Three variations on gametophyte/sporophyte relations
Page 598 Bryophytes
Sporophyte dependent on gametophyte Gametophyte-dominant life cycle, the dependent sporophyte is nourished by the gametophyte as it grows out of the archegonium

13. Pteridophytes: seedless vascular plants
Ferns, club ‘moss’, horsetails
True roots and leaves
Roots have lignified vascular tissue
Sporophyte-dominant life cycle
Homosporous plants: a single type of spore….
Sporophyte---->Single type of spore >Bisexual gametophyte >Eggs; sperm (flagellated; damp locations)
Carboniferous period plants

14. Pteridophytes
P. 598 Large sporophyte and small independent gametophyte (fern)
Sporophyte is dominant generation
Gametophyte is small, photosynthetic and free-living (not dependent on the sporophyte for their nutrition.

15. Life Cycle of a Fern

16. Fern Frond