First Lecture

Alga - singular, Algae - plural

Algae orders are highly specialized and distinct. Classifications change frequently.

Originally classification was on color and form only.
1800's light microscopy
1935 - 1980 16 different major classification schemes published
1960's Electron microscopy - ultrastructure
    1. Mitosis and Cytokinesis
    2. Flagellar apparatus
    3. Cell coverings and scales
1980's Molecular level
    1. PCR
    2. Gene mapping

Time line

Estimates:
3.5 - 3.7 billion yrs ago, first cyanobacteria CO2 = 10% of atmosphere
2004 CO2 concentration = .038% or 380 ppm

As blue-green algae multiplied more O2 released into atmosphere that acted as a toxin to anaerobic life forms and lead to the appearance of eukaryotes. (part of Gaia Hypothesis)

The earliest multi-celled organism was a red algae or Rhodophyta (about 1 billion years old)

Taxonomy:

Division or Phylum for algae

(Kingdom)-- algae {Eukaryotes with the Protista, prokaryotes with Monerans}
Division
Class
Order
Family
Genus
Species

Example:
Division: Chlorophyte
Class: Ulvophyceae
Order: Ulvales
Family: Ulvaceae
Genus: Ulva
Species: lactuca
Common name: "sea lettuce"

Major Divisions:

Prokaryotes

Cyanobacteria (Bluegreen algae or Cyanophyta)

All three are different names for the same organism (Blue-Green algae)
 

 Eukaryotes 2 membranes around chloroplast

Division Rhodophyta (Red Algae)

Division Chlorophyta (Green Algae)

3 membranes around chloroplast

 Division Orchrophyta (Brown algae, diatoms, and others)

Unicellular flagellated organisms

 Division Haptophyta

Division Dinophyta - (dinoflagellates) (red tides/ Pfisteria)

Division Euglenophyta

Division Cryptophyta

PRIMARY FACTORS

  1. Light harvesting pigments
  2. Polysaccharide reserves
  3. Cellular organization
  4. Molecular phylogeny
  5. Morphology
  6. Ecology
 1. Algae orders identified by photosynthetic pigments

all algae have Chlorophyll a a strong indication that there is a common alga ancestor

Chlorophyll a absorbs light between 400 - 700 nm

PAR- Photosynthetic Active Radiation (the light radiation of absorption)

wavelength = 400 nm - blue ----------------------------------- 700 nm - red

Accessory pigments- extra pigments to help chlorophyll a attract and absorb more efficiently

Pigments

Blue Green- (Cyanobacteria)

Greens (Chlorophyta) Reds (Rhodophyta) Browns (Chromophyta) The above aid in growth in deeper water with less light.

Cell structure:

Cyanobacteria- Contain Thylakoids - Photosynthetic pigment also in chloroplasts of other algae

Cell divides by furrowing- pinch off in middle and divide up organelles and split nucleus and chloroplast.

Alga bodies are called THALLUS

They take several forms:

Life cycles Cells undergo meiosis and produce gametes

which fuse to

form zygotes

Which then form thallus
 

 Cell undergoes meiosis produces haploid spores