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

Charophyceans Homologous Cell Walls Peroxisome enzyme

(Photorespiration) Homologous

Chloroplasts Sperm ultrastructure Phragmoplasts (Mitosis

& Cytokinesis) Genetic Relationships

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

Mosses– Hepatophyta

Liverworts– Anthocerophyta

Hornworts

Vascular Seedless plants– Lycophyta

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

BryophytaMosses

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