Review of Plant Diversity Bryophytes non-vascular land plants Pteridophytes seedless vascular plants Gymnosperm pollen & “naked” seeds Angiosperm flowers & fruit flowering plants conifers flowers mosses ferns pollen & seeds vascular system = water conduction colonization of land Ancestral Protist

A Review of Alternation of Generations… Plant How is this different from animal life cycles? diploid multicellular sporophyte 2n mitosis zygote 2n A Gametophyte is: A Sporophyte is: fertilization meiosis gametes 1n spores 1n mitosis mitosis haploid multicellular gametophyte 1n alternation of generations

First land plants Bryophytes: mosses & liverworts non-vascular cuticle Where must mosses live? Bryophytes: mosses & liverworts non-vascular no water transport system no true roots cuticle prevents drying out swimming sperm flagellated sperm lifecycle dominated by haploid gametophyte stage fuzzy moss plant you are familiar with is haploid spores for reproduction haploid diploid Why can’t mosses grow large?

Bryophytes: mosses & liverworts

Liverwort

Moss

“Peat Moss” Peat Bog

Bryophyte significance Food for mammals and birds Prevent soil erosion along streams Commercially – peat moss (Sphagnum) is used as a fuel, a soil conditioner, and by florists

FERNS An important group of plants – 10,000 species exist! Selaginella Psilotum Horsetails Ferns

First vascular plants Pteridophytes: ferns vascular swimming sperm diploid Pteridophytes: ferns vascular water transport system xylem, phloem, roots, leaves swimming sperm flagellated sperm life cycle dominated by sporophyte stage leafy fern plant you are familiar with is diploid fragile independent gametophyte (prothallus) spores for reproduction haploid cells which sprout to form gametophyte Where must ferns live? haploid

Alternation of generations Fern gametophyte (1n) small haploid plant which produces gametes archegonia antheridia

Alternation of generations diploid produces male & female gametes archegonia haploid antheridia

Fern sporophyte body parts Fern sporophyte has fronds (leaves) Young fronds are called fiddleheads They also have an underground horizontal stem called the rhizome True roots come from the rhizome

Rhizome

Fronds Under the fronds, spores are produced in sporangia in clusters called sori (sorus = singular) Spores grow into the gametophyte The gametophyte grows the sporophyte The sporophyte makes more spores

Significance of ferns Ecologically important: Hold and form soil to prevent erosion As food – fern fiddleheads eaten in Hawaii, Japan, Philippines – very nutritious and delicious! As ornamental plants Coal formation from ancient ferns

Early Pteridophytes: Tree Ferns Carboniferous forest – 290-350 mya Forests of seedless plants decayed into deposits of coal & oil

Pteridophytes: Tree ferns fronds fiddleheads

More seedless vascular plants… Club Moss

Horsetail

What next…? What major problems do bryophytes and pteridophytes face? What features do more advanced plants have that deal with these problems?