[2] Seaweeds

• Chlorophyta, Rhodophyta, and terrestrial plants arose via a single event of plastid endosymbiosis
• Cyanobacteria eventually become a chloroplast
• Secondary plastid endosymbiosis is applicable only to Phaeophyta and Stramenopiles
• Assembly of populations of different organisms growing on intertidal or submerged artificial structures

  Fouling community

  
• Environmental factors most influential on seaweed zonation

  1. Temperature
  2. Light
• Summer is the best time for algal spores to be released
• Higher temperature is more conducive to seaweed growth
• Adaptation dependent on different absorption spectra of chlorophylls


  Chromatic adaptation

  
• Chlorophyta - Green algae

  Rhodophyta - Red algae

  Phaeophyta - Brown algae
• Red algae survive the deepest conditions as they can best absorb the color blue
• Other environmental factors that affect seaweed zonation:

  1. Tidal exposure and desiccation
  2. Wave action
  3. Salinity
  4. Availability of nutrients
• Label the ff. figure

  A) Holdfast

  B) Stipe

  C) Blade

  D) Air bladder

  E) Reproductive structures

  
• Seaweed part that allows attachment to substrate

  Holdfast
• Flexible part of the seaweed with the purpose of support

  Stipe
• Entire surface above stipe

  Blade
• Gas-filled seaweed structure that allows for buoyancy

  Air bladder
• Type of seaweed structure that looks like a colony of different cells

  Filamentous
• Seaweed that grow similar to corals

  Coral-like algae
• Type of Chlorophyll:

  1. Chlorophyta - Chlorophyll B
  2. Phaeophyta - Chlorophyll C
  3. Rhodophyta - Chlorophyll D
• Types of accessory pigments:

  1. Carotenes
  2. Xanthophylls
  3. Phycobilins
• Additional cell wall components:

  1. Chlorophyta - cellulose
  2. Rhodophyta - carrageenan
  3. Phaeophyta - alginates
• Types of food storage:

  1. Chlorophyta - Starch formed in chloroplasts
  2. Rhodophyta - Starch formed in cytoplasm
  3. Phaeophyta - Laminarin
• Reproductive stages:

  1. Chlorophyta - Sporophyte and gametophyte
  2. Rhodophyta - Carposporophyte and tetrasporophyte
  3. Phaeophyta - Sporophyte and heterokont spores, receptacles