Seedless vascular plants Flashcards
Viridiplantae
A monophyletic clade that includes green algae and plants
Otherwise green algae form paraphyletic group
Bryophyte dominant life stage
Gametophyte
-free living
-dominant
Vascular plants dominant life stage
-sporophyte
Gametophyte is small and dependent on sporophyte
Zygotes meiosis
Zygote-meiosis-haploid cells-haploid individual-gametes-zygote
Little diploid phase
Gametic meiosis
Zygote-diploid individual-meiosis-4 gametes-fertilization
Less haploid phase
Sporic meiosis
zygote-diploid individual-meiosis-spores-haploid individual-gametes-fertilization
-2 multicellular adult forms and spores
Extinct Phyla of SVP have which characteristics
-simple structure
-no roots or leaves
-stem: vertical, dichotomous branching, photosynthetic
-rhizomes
-sporangia
Rhyniophyta characteristics
-extinct SVP
-terminal sporangia
-sporangia open on one side
-xylem cells matured first in the enter of the stems
-fertile stems sometimes shorter than sterile stems
Zosterophyllophyta characteristics
-extinct SVP
-sporangia terminal on short lateral branches at top of major stems
-sporangia open at top
-xylem matured centripetal (same as lycophyta)
Trimerophytophyta characteristics
-extinct SVP
-complex branching
-extensive overtopping (one of the branches keeps growing more than the rest): central branch with many short branches with terminal sporangia
When were SVP the dominant plant species
Carboniferous forest era
362-290 MYA
Current SVP characteristics
-independent gametophytes and sporophytes
Gametophytes:
-short lived
-much smaller than sporophyte
Sporophytes:
-Homosporous
-heterosporous: produce unisexual sporangia (rare in SVP)
Heterosporous species produce what type of spores
Megaspores -become Megagametophyte
Microspores - become microgametophyte
What are leaves
-vascularization
-determinant growth
-bilateral symmetry
-defined arrangement (phyllotaxy)
Microphylls
Vs
Megaphylls
-small
-singular vascular trace
-no leaf gap
-sporangia phyllotaxy
-variable size
-highly branched vascularization
-leaf gaps
-ferns, seed plants
Telome theory of microphyll evolution
Microphylls evolved as a result of the reduction of existing telomes
Megaphyll confusion
Megaphylls are not homologous between species
Three orders of Lycopodiophyta
Lycopodiales
Selaginellales
Isoetales
All eusporangiate
Lycopodiales sporophyte characteristics
-400 species
-mostly tropical, temperature, epiphytic
-sporophytes (club mosses)
-branching rhizomes (photosynthetic)
-Sporophylls spirally arranged
-sporangia on adaxial surface of Sporophylls
-strobili: grouped Sporophylls
-Homosporous
Lycopodiales gametophyte characteristics
-bisexual
-may take 6-15 years to mature
-green, irregularly lobbed masses
-subterranean, non photosynthetic, mocrorrhizal
What type of Lycopodiophyta does not have strobilus
Huperzia lucidula
Selaginellales sporophyte characteristics
-750 species
-tropical, deserts, epiphytic
-spike mosses
-ligule: basal, adaxial on microphylls
-sporangia on adaxial surface of Sporophylls
-hererosporous—> unisexual gametophytes
-megasporophylls
-microsporophylls
Selaginellales gametophyte characteristics
-endosporic development (inside spore wall)
-non photosynthetic (except some females)
-biflagellate sperm
Isoetales sporophyte characteristics
-150 species
-closely related to lycophyte from Carboniferous
-aquatic or seasonally submerged
-sporophytes called quillworts
-expanded from, roots, microphylls
-vascular cambium
-heterosporous, adaxial sporangia
-some without stomata, use CAM, carbon from sediment
