ALGAE

PLANT-LIKE PROTISTSPLANT-LIKE PROTISTS

Photosynthesis of algae generate 3/4 of the oxygen on Earth.

Eukaryotic Autotrophs beginning of all food chains

1. Euglenoids: Phylum Euglenophyta

Possess traits of both plants & animalsanimal- responsive, move by

1 or 2 flagellaplants- contain chlorophyll

and photosynthesize

NO cell wall, but flexible interlocking protein fibers outside cell membrane

Reproduction- asexual by mitosis

Eyespot- red, light sensitive aides in moving to light.

Reservoir- water collected and stored for later use

2. Diatoms:2. Diatoms:Phylum BacillariophytaPhylum Bacillariophyta

photosynthetic, unicellular live in marine & fresh waters Shells- shaped like small boxes

with lidmade of silicatwo halves called frustules

divided into 2 major groups according to shape

1. radial symmetry

2. long, distinct right and left shapes

Reproduction- asexual & sexual

Asexual: two halves of box separate, each half makes new half shell to fit

inside itself, Each generation smaller than

parent, when each reaches 1/4 original size,

sexual reproduction takes place

Sexual reproduction: gametes form and fuse to form new diatoms.

Individuals divide asexually

Contain chlorophyll, autotrophs food formed as oils (not starch)

fish that feed on them have unpleasant oily taste (cod liver oil)

shells mined from ocean

used to polish metal, added to road paint for sparkle in line

3. Phylum: Dinoflagellata3. Phylum: Dinoflagellata

some are unicellular algae cell walls: thick cellulose plates movement- 2 flagella located in

grooves at right angles

cause cell to spin-“sea whirlers”

autotrophs, contain chlorophyll and red pigment

different types such as:

a. luminescent- green glow

b. poisonous toxins

Gonyaulax catanellaGonyaulax catanella

Produces an extremely strong nerve toxin that can be lethal

in summer may cause the “red tide”- gives birds and fish respiratory failure, humans who eat oysters, clams, etc. poisoned

Pfisteria piscicidaPfisteria piscicida Produces an extremely strong

toxin (poison) N.C. researchers discovered it

(1988) causes a number of fish kills in the coastal areas of N.C.

4. Green Algae:4. Green Algae: Phylum Chlorophyta Phylum Chlorophyta

•Most diverse of all algae,Most diverse of all algae,Green and yellow pigment,Green and yellow pigment,Most live freshwater, some inMost live freshwater, some in moist soil, surface of tree moist soil, surface of tree trunks, on snow trunks, on snow some in cells and body some in cells and body cavitiescavities

ChlamydomonasChlamydomonas- - simplest of unicellular simplest of unicellular algaealgae

Spirogyra-form multicellular filaments

Spirogyra:Spirogyra:Asexual ReproductionAsexual Reproduction-- filament breaks up, filament breaks up, each grows into new each grows into new filament by mitosisfilament by mitosis

SexuallySexually by conjugation: by conjugation: filament lines up, tubes form

between cells contents flow into adjacent cell, material fuses & forms a diploid zygote

thick wall forms around zygote- now called a “zygospore” which goes through meiosis

forms haploid spirogyra filament

Volvox colonyVolvox colony

hollow ball made of 500-600 unicellular flagellated organisms arranged in a single layer held by strands of cytoplasm

flagella face outward as the colony spins through water.

5. Red and Brown Algae:5. Red and Brown Algae:Phylum Rodophyta (Red) and Phylum Rodophyta (Red) and Phaeophyta (Brown)Phaeophyta (Brown)

Red and Brown Seaweed Red Algae- multicellular,

marine organism tropical water or rocky coasts of cold waters.

-attach to rocks by structures called“holdfasts”

-photosynthesize

-absorb blue light waves (only part of light spectrum that penetrates water over 100 m).

Brown Algae or Kelp largest, most complex protist found in cold, coastal water Adaptation: air bladder- keep

organism near surface to absorb light for photosynthesis

anchored at bottom by “hold fast”

Reproduction:

Alternate haploid and diploid generation.

-haploid form called the gametophyte which produces the gametes.

The two gametes form diploid zygote

zygote divides by mitosis-> diploid cells called sporophyte

Sporophyte undergoes meiosis and forms haploid spores.

Haploid spores--> develop into haploid algae gametophyte cycle goes again

DID YOU KNOW?????DID YOU KNOW????? Japanese industry raise algae as

a food source. Many dairy products contain

thickening agents such as algin and carrageenan that are made from red and brown algae.