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

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