Seedless Plants
Plant
Evolution
Plant Evolution
Nonvascular Seedless plants
– (Ordovician - 475 mya)
Vascular Seedless plants
– (Devonian - 400 mya)
Vascular Seed plants
– (Carboniferous - 360 mya)
Flowering plants
– (Cretaceous - 130 mya)
Plant Evolution
(Common with Algae)
Multicellular and Eukaryotic
Cell walls made of Cellulose
Chlorophyll a and b
Store excess sugar as starch
Adaptations to Terrestrial Life
Apical Meristems
Multicellular Dependent Embryos
Alternation of Generation
Walled Spores produced in Sporangia
Other Adaptations
– Cuticle, stomata, Xylem & Phloem, secondary compounds
Apical Meristems
Multicellular Dependent
Embryos
Alternation of Generation
Walled Spores produced in
Sporangia
Other Adaptations
Adaptations in
Shallow Water Algae
Subjected to occasional drying
Protection of gametes and embryos in gametangia
Sporopollenin
Classification of Seedless
Plants
Nonvascular Seedless plants
– Bryophyta
Vascular Seedless plants
– Lycophyta
Mosses
– Hepatophyta
Liverworts
– Anthocerophyta
Hornworts
Club mosses
– Psilophyta
Whiskferns
– Spenophyta
Horsetails
– Pterophyta
Ferns
Nonvascular Seedless Plants
Plant is a thallus (no vascular tissue)
– no true leaves, roots, stems
Embryophytes
– gametangia
(antheridium and archegonium)
– sporangium (produces spores)
Hepatophyta
Liverworts
– Two forms
leafy (80%)
thalloid (20%)
Hepatophyta
Liverworts
– Reproduction
asexual
(gemmae cups)
sexual
Anthocerophyta
Hornworts
– Similar to liverworts except for sporophytes
– Most closely related to higher plants
Bryophyta
Mosses
Bryophyta
Mosses
Vascular Seedless Plants
Formation of vascular tissue
– Xylem (water)
– Phloem (food)
– True leaves, roots, and stems
Lignin
Sporophyte generation dominate
Sperm with flagella
Lycophyta
Lycophytes
– true leaves
microphylls
– true stems
– true roots
– sporophylls
leaves that produce spores
Psilophyta
Whisk Ferns
– no true leaves
– no true roots
Sphenophyta
Horsetails
– true leaves
microphylls
– true stems
silica
– true roots
Division: Pterophyta
Division: Pterophyta
Fern Life Cycle