2 19 Biology Notes What is a plant Eukaryotic Multicellular Autotroph photosynthetic Alternation of Generations The life cycle includes both multicellular haploid and diploid stages Gametophyte is haploid produces gametes via mitosis Sporophyte is diploid produces spore through meiosis Fig 21 1 What is the difference between a spore and a gamete both are haploid difference is what they can develop into Spores can develop into a multicellular individual without fusing with another cell Gametes can not they need to fuse with another gamete Plant diversity Four major groups of plants Fig 21 4 Non vascular plants Bryophytes Motile gametes flagellated sperm require water for reproduction No vascular tissue therefore they are short Gametophyte stage is dominant Ex Hornworts Liverworts Moss Fig 21 6 Seedless Vascular plants Ferns Have vascular tissue Xylem and Phloem conduct water and materials throughout the plant Motile gametes flagellated sperm require water for reproduction The sporophyte generation is now the dominant Q Vascular tissue allows plants to be taller What is the advantage to ferns A Better dispersal of spores and less competition for light Ex Club moss Fern Horsetail Tree Fern Fig 21 8 Seed Plants Gymnosperms Groups Cycadphyta Ginkophyta Gnetophyta Coniferophyta Has vascular tissue Pollen not flagellated sperm don t need water for reproduction Gametophyte reduced now living on sporophyte Seeds Q What is the advantage to having pollen A better dispersal of gametes Q What is the advantage to having a seed A Better protection of the young embryos and better dispersal of the young embryos Ex Ginkgo Cycad Gnetophyte Conifer Fig 21 11 Flowering Plants Angiosperms Has vascular tissue Pollen not flagellated sperm Gametophyte reduced now living on sporophyte seed flowers and fruits Q What is the advantage to having flowers A better dispersal of the gametes
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