Download
1 / 9
90 likes | 333 Views
Plant reproductive modes. Adaptations for terrestrial life (ancestors were multicellular green algae). History of plant evolution. Plants had to overcome need for water to:. Reproduce. Provide structural support. How are new organisms produced?. Plant reproductive modes.
E N D
Plant reproductive modes • Adaptations for terrestrial life (ancestors were multicellular green algae) • History of plant evolution • Plants had to overcome need for water to: • Reproduce • Provide structural support How are new organisms produced?
Plant reproductive modes • 12 living phyla (divisions) of plants • 3 phyla are non-vascular (no specialized cells for transport of water and carbohydrates such as xylem or phloem) • Simple plant taxonomy • Phylum Bryophyta (mosses) • 9 phyla are vascular (plants with vascular tissue) • Seedless vascular plants: • Phylum Pterophyta (ferns) • Seed plants: • Gymnosperms (Phylum Coniferophyta): plants with ovules exposed at fertilization • Angiosperms (Phylum Anthophyta): plants with ovules enclosed within flower tissue at fertilization How are new organisms produced?
Plant reproductive modes • Evolutionary pattern seen in reproductive modes of plants: • Less reliance on water • Increasing protection of embryo • Reduced haploid stage of life cycle • All plant life cycles are haplodiplontic (= both haploid and diploid stages are multicellular) • Animal life cycles are diplontic (= only diploid stage is multicellular) How are new organisms produced?
mitosis mitosis syngamy meiosis mitosis Plant reproductive modes egg Haploid stage Gametophyte (gamete-producing, haploid plant) • Generalized life cycle of plants: + sperm Gametangia (structure where gametes produced) spores Spore mother cell(diploid cell that undergoes meiosis to produce haploid spores) zygote embryo Sporangia (structure where spores produced) Sporophyte (spore-producing, diploid plant) Diploid stage How are new organisms produced?
Moss Liverwort Hornwort Plant reproductive modes • Nonvascular plants (e.g. Phylum Bryophyta) • Small, unspecialized plants (no true leaves or roots) • Comparison of reproductive modes of plants: • Sporophyte attached and (usually) nutritionally dependent on dominant gametophyte • Reproduction completely dependent on water How are new organisms produced?
Plant reproductive modes • Nonvascular plants (e.g. Phylum Bryophyta) • Comparison of reproductive modes of plants: How are new organisms produced?
Plant reproductive modes • Seedless vascular plants (e.g. Phylum Pterophyta) • More specialized plants (true leaves and roots) • Comparison of reproductive modes of plants: • Sporophyte dominant stage of life cycle; gametophyte reduced (unspecialized) and independent • Reproduction completely dependent on water • Embryo slightly protected in archegonia How are new organisms produced?
Plant reproductive modes • Seedless vascular plants (e.g. Phylum Pterophyta) • Comparison of reproductive modes of plants: How are new organisms produced?
Plant reproductive modes • Other seedless vascular plants with similar life cycles • Comparison of reproductive modes of plants: How are new organisms produced?
