CHAPTER 29 PLANT DIVERSITY I: HOW PLANTS COLONIZED LANDFerns in a Tasmanian Forest

Highlights of Plant Evolution

Charophyceans-green algae most closely related to land plants

Charophyceans-green algae most closely related to land plants

Charophyceans homologies with land plants:

Chloroplasts

Rosette cellulose-synthesizing complexes

Almost identical enzymes in their perioxisomes

Formation of a phragmoplast during

cytokinesis and cell plate formation

Sperm

rRNA and cytoskeletal proteins

Apical meristem

Apical meristems of plants shoots and roots

Embryo of a Liverwort

Maternal tissue of the archegonium

Embryo

Embryo of an Angiosperm

Endosperm

Maternal tissue of the archegonium

Embryo

Integuments

Alternation of generations

a generalized

scheme

Division Pterophyta - a fern spore

Sporangium of a Hornwort

Spores

Sporangium tissue

Archegonium of a liverwort

egg

Antheridium of a Liverwort

Sperm

Pterophyta stem

Waxey cuticle

Pterophyta Stem

PhloemXylem

Phloem Xylem

Fossilized tissue of a sporophyte and spores

Hypothetical mechanism for the origin of alternation of generations in the ancestor

of plants

Liverworts

Liverworts

Hornworts

Phylum Bryophyta

Sporophytes

Gametophytes

Multicellular with specialized cells and tissues but they do not contain any vascular tissue which restricts their size.

Bryophytes Mosses--Sporophyte

Bryophytes Mosses—

Gametophyte

Archegonia and antheridia grow on separate stalks of the same gametophyte so splashing water is required to transfer the sperm to the egg

Bryophytes Mosses

Bryophytes Mosses Gametophytes

Quillwort

Life Cycle of a MossBryophyte

Life Cycle of a MossBryophyte

Life Cycle of a MossBryophyte

Bryophytes Mosses--Gametophyte

Bryophytes Mosses—Gametophyte

SpermEgg

Archegonium

Bryophytes Mosses--

Sporophyte

Sporangium

Bryophytes Mosses--Spores

Bryophytes Mosses--Protonema

Small Sporophyte of

a liverwort

Bryophytes Moss--Sporangium

Sphagnum Moss

Sphagnum MossGametophyte Sporophyte

Sphagnum leaf

Peat Bog

Fossil of an early plant with vascular tissue

protracheophyte & polysporangiophytes

SporophyllsLycophyta-Club

Moss

SporophyllsLycophyta-Club Moss

Whisk Fern

Division Sphenophyta-Horsetails

Silica in cell walls makes them abrasive. Sporophyte is predominant generation; homosporus;

Division Sphenophyta-

Horsetails

Pterophyta-Ferns

Branched vascular systems evolved by the fusion of branched stems

Pterophyta-Ferns Life Cycle

Pterophyta-Ferns-fronds-sporophyte

Pterophyta-Ferns-Sorus

Pterophyta-Ferns-Sporangium

Pterophyta-Ferns-Sporangium

Pterophyta-Ferns-Spore germinating

Pterophyta-Ferns-Gametophyte Antheridia Archegonia

Pterophyta-Ferns-

ArchegoniaSperm are flagellated and must swim in condensation which forms under the gametophyte to the archegonia

Young sporophyte growing out of gametophyte

Pterophyta-Ferns-fronds-sporophyte

Pterophyta-Ferns-sporophyte-Sori

Pterophyta-Ferns-sporangia in a sorus

Carboniferous forest