Chapter 29 Biology Chlorophytes Charophytes and Plantae Multicellular Chloroplasts with same pigments Cell wales with cellulose Storage molecules as starch Charophytes also share with Plantae similar flagellated sperm cellulose synthesis proteins cytokinesis process Sporopollenin durable polymer that protects 470 million years ago multicellular green algae expanded from shallow seas into rivers and lakes Green algae along lake shores more resources less competition Subjected to periodic dehydration Populations with land adaptations thrive Advantages of Land CO 2 higher Light intensity higher More minerals No herbivores No competition Disadvantages risk of desiccation Divided resources No support in air First plants were similar to today s liverworts Derived Characteristics of Plants 1 Alternation of generations a Plant sporophyte 2n makes huge unique diverse offspring per fertilization Compare to charophyte life cycle only multicellular is haploid Zygote does meiosis to produce only 4 diverse offspring 2 Walled haploid spores a Dispersal through air sporopollenin protects the spores Egg protected with in archegonium Fertilization here forming zygote 3 Sporophyte embryos grow protected within female gametophyte 4 Apical Meristems a Continuously dividing cells b Roots and shoots grow toward resources 5 Waxy Cuticle a Waxy Coat stops desiccation b Pores needed to allow CO 2 O 2 exchange 6 Secondary Compounds a Chemicals that deter repel or poison competitors herbivores and parasites 7 Mycorrhizae a Mutualism with fungi helps water and mineral absorption b Dates back to first land plants before true roots Diversification of Plants One bryophyte like ancestor of all plants About 470 mya Key adaptations major plants and algae Bryophytes mosses Liverworts Phylum Hepatophyta Hornworts Phylum Nathocerophyta Haploid gametophyte is dominant form Makes eggs and flagellated sperm Most are small and grow in dark damp areas Lakes vascular and supportive tissues Very thin body depends on diffusion With rhizoid for attachment Diploid sporophyte depends on gametophyte for food and water Grows within archegonium
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