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Land plants: origins seedless plants. Biol 121, Fall 2010, Tom Buckley. 22 Sep 10. Brown and golden algae. Phylogeny of land plants. green algae. green algae. land plants. green algae. 2n. embryo. Probable ancestor: algae at lake edges (periodic drying). Plant evolution.
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Land plants: • origins • seedless plants Biol 121, Fall 2010, Tom Buckley 22 Sep 10
Brown and golden algae Phylogeny of land plants green algae green algae
land plants green algae 2n embryo
Plant evolution land plants aquatic ancestors vascular plants nonvascular plants seedless vascular plants seed plants naked-seeded plants vessel-seeded plants green algae mosses ferns conifers flowering plants
Diversification of land plants # of spp 9,000 100 15,000 1,200 12,000 800 250,000 seedless plants seed plants Fig 29.7
Diversification of land plants gametophyte = dominant sporophyte = dominant Fig 29.7
walled spores produced in sporangia Characters of land plants function of spores?
apical meristems Characters of land plants function of apical meristems?
Phylum Bryophyta (mosses) Phylum Hepatophyta (liverworts) Phylum Anthocerophyta (hornworts)
liverwort hornwort
hydroids leptoids photosynthetic cells stem x.s. leaf x.s. bryophyte anatomy
photosynthetic cells leaf x.s. epidermis bryophyte anatomy hornwort stoma
Bryophyte life cycle Fig 29.8
Bryophyte life cycle gametes produced in gametangia male: antheridia female: archegonium Fig 29.8
Bryophyte life cycle Fig 29.8
Bryophyte life cycle Fig 29.8
Seedless vascular plants Phylum Pterophyta (ferns, horsetails & relatives) Phylum Lycophyta ("club mosses" & relatives)
Isoetes sp. ("quillwort") tree fern
Seedless vascular plants: new features Sporophyte is dominant nonvascular vascular Vascular tissue makes large plants possible Sporophylls: modified leaves that bear sporangia permits complex reproductive structures
Sporangium: spore container Fern life cycle
indusium sorus Sorus (pl. sori) = cluster of sporangia
Horsetails (Equisetum) Strobilus (pl. strobili) = cluster of sporangia
Horsetails (Equisetum) sporangium sporophyll
Synangium = cluster of 3 fused sporangia Whisk fern (Psilotum)
Phylum Lycophyta Club moss (Lycopodium) Spike moss (Selaginella)
A Moss (Phylum Bryophyta) Q: What is the ploidy level of the tissues indicated by arrows? A B (a) n n (b) n 2n (c) 2n n (d) 2n 2n B
Q: In which of the following are gametes haploid? (a) Phylum Bryophyta (b) Phylum Pterophyta (c) Phylum Lycophyta (d) All of the above
Alternation of generations meiosis meiosis diploid haploid diploid haploid syngamy syngamy