Red Algae + Intro to Non Vascular Plants

Phylum Rhodophyta

Habitats: Marine and Freshwater

Pigments: Contain mostly Phycoerythrin (red pigment)

  • This breaks down when algae dies = white color

  • Also absorbs blue light, for deeper habitats

Special Features

  • Floridian Starch: (similar to laminarin in brown algae) used for carb storage.

  • Carrageenin (in Irish moss): Protective outer layer for red algae similar to algin in brown

    • A cell wall polysaccharide used as a thickening agent

Nori for Sushi - made into thin glossy white sheets

Unique Life Cycle (Alt. of Generations)

Has 3 generations = 1 Gametophyte + 2 Sporophytes (Tetro-spore and Carpospore 2n)

  1. 2n Tetro-sporophyte produces 1n Tetro-spores

  2. Those make their way to a male + female Gametophyte

  3. Male gametangia sends sperm to Female gametangia to form 2n Zygote

  4. Inside the Pericarp of female gametangia, Carpo-sporophyte produces 2n Carpospores

  5. That spore germinates in to Tetro-spore (Restarts)

Non Vascular Plants - No Xylem or Phloem

Consists of Liverworts (Hepatophyta), Hornworts (Antocerophyta), and Mosses (Bryophyta)

Green Algae → Plants

  • Plants only share some similarities with Algae: Pigments, starch storage, cell division, and cellulose in cell walls

5 Major Key Trait Differences

  1. ALL plants have Alt. of Generations; Charophyceae has Zygotic

    • Angiosperms - Sporophyte Dominant; Everything Else - Gametophyte Dominant

  2. Plants have sporopollenin-walled spores for protection

  3. Nourishment dependent Embryophyte (multicellular embryo protected by tissue)

  4. Multicellular Gametangia (Anther = Male; Arche = Female)

  5. Apical Meristems for primary growth (root and shoot tip growth)

Evolutionary timeline of Plants

  • Silurian Period (440 - 410 mya)

    • Plants invade Earth

  • Devonian Period (410 - 360 mya)

    • Early Tracheophytes

  • Carboniferous Period (360 - 290 mya)

    • Seedless Tracheophyte forests, Origin of Seeded Tracheophytes

  • Permian Period (290 - 250 mya)

    • Most Gymnosperms present

  • Triassic Period (250 - 215 mya) + Jurassic Period (215 - 145 mya)

    • Dominance of cycads + conifers

  • Cretaceous Period (145 - 65 mya)

    • Angiosperm origin and spread

Trends in Plant Evolution

  • Nonvascular --> Vascular

  • Haploid --> Diploid Dominance

  • Homospory --> Heterospory

  • Motile Gametes --> Nonmotile

  • Seedless --> Seeds