Introduction: the conquest of land continues...
bryophytes -- the bare minimum for adaptation to terrestrial environment
vascular plants -- improvements and diversification
protracheophytes
Rhyniophyta
the microphyll line
Zosterophyllophyta
Lycophyta
the megaphyll line
Sphenophyta
Psilotophyta
Pterophyta
seed plants...
Evolutionary changes (1-5)
1. different life cycles
independence of the sporophyte
dominance of the sporophyte
isomorphic vs. heteromorphic alternation of generations
advantages
2. multiple sporangia
need to be able to branch
advantages
3. lignified vascular tissue
xylem: tracheary elements
from hydroids to tracheids
advantages
phloem
4. organization
shoots vs. roots
tissue systems
- dermal
- ground
- vascular
- protosteles
- siphonosteles
- eusteles
branching pattern
dichotomous
a central axis with smaller branches
early vascular plants
protracheophytes
vascular tissue
sporangia
isomorphic generations(?)
Rhyniophyta
vascular tissue
dichotomous branching
terminal sporangia
5. the evolution of microphyll and megaphyll leaves
the microphyll line
Zosterophyllophyta
no roots, leaves
vascular tissue
sporangia on short lateral branches
Lycophyta -- were dominant trees during the coal age
Lycopodiaceae -- club mosses (Lycopodium)
morphology and life cycle
sporophyte
- leaves
- stems
- roots
- strobili
gametophyte
- dependent on fungi
homosporous life cycle
Selaginellaceae -- spike mosses (Selaginella)
morphology and life cycle
- leaves
- stems
- roots
- strobili
gametophytes
- mega- and microgametophytes
heterosporous life cycle
Isoetaceae -- quillworts (Isoetes)
semiaquatic
heterosporous
secondary growth and extinct trees
the megaphyll line
Sphenophyta -- horsetails (e.g., Equisetum)
intro
range and habitat
extinct genus (Calamites) was a tree
morphology and life cycle
sporophyte
stem
whorled leaves/branches
strobilus
spores
elaters
homosporous
gametophyte
economic use
Psilotophyta
morphology and life cycle
simple sporophyte
gametophyte and sporophyte dependent on fungi
homosporous
Pterophyta
intro
economic uses
special characteristics and terminology
structure of frond (= leaf)
rhizome
sporophylls and sori
fiddleheads
diversity
order Filicinales
- most ferns
- have leptosporangia
- are homosporous
water ferns
- have leptosporangia
- are heterosporous
- are aquatic
eusporangiate ferns
- two orders
- are homosporous
- have a Psilotum-like gametophyte
- have eusporangia
- eusporangia vs. leptosporangia
click here to go to seedless vascular plant vocabulary
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