ALGAE PLANT-LIKE PROTISTS

u Photosynthesis of algae generate 3/4 of the oxygen on Earth. u Eukaryotic Autotrophs u beginning of all food chains

1. Euglenoids: Phylum Euglenophyta

u Possess traits of both plants & animals u animal- responsive, move by 1 or 2 flagella u plants- contain chlorophyll and photosynthesize

u NO cell wall, but flexible interlocking protein fibers outside cell membrane u Reproduction- asexual by mitosis u Eyespot- red, light sensitive u aides in moving to light.

u Reservoir- water collected and stored for later use

2. Diatoms: Phylum Bacillariophyta

u photosynthetic, unicellular u live in marine & fresh waters u Shells- shaped like small boxes with lid u made of silica u two halves called frustules

u divided into 2 major groups according to shape 1. radial symmetry 2. long, distinct right and left shapes u Reproduction- asexual & sexual

u Asexual: u two halves of box separate, u each half makes new half shell to fit inside itself, u Each generation smaller than parent, u when each reaches 1/4 original size, sexual reproduction takes place

u Sexual reproduction: gametes form and fuse to form new diatoms. u Individuals divide asexually

u Contain chlorophyll, autotrophs u food formed as oils (not starch) fish that feed on them have unpleasant oily taste (cod liver oil) u shells mined from ocean used to polish metal, added to road paint for sparkle in line

3. Phylum: Dinoflagellata

u some are unicellular algae u cell walls: thick cellulose plates u movement- 2 flagella located in grooves at right angles cause cell to spin-“sea whirlers”

u autotrophs, contain chlorophyll and red pigment u different types such as: a. luminescent- green glow b. poisonous toxins

Gonyaulax catanella u Produces an extremely strong nerve toxin that can be lethal u in summer may cause the “red tide”- gives birds and fish respiratory failure, humans who eat oysters, clams, etc. poisoned

Pfisteria piscicida u Produces an extremely strong toxin (poison) u N.C. researchers discovered it (1988) causes a number of fish kills in the coastal areas of N.C.

4. Green Algae: Phylum Chlorophyta

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

Chlamydomonas- simplest of unicellular algae

u Spirogyra-form multicellular filaments

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

Sexually by conjugation: u filament lines up, tubes form between cells contents flow into adjacent cell, material fuses & forms a diploid zygote

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

Volvox colony

u hollow ball made of unicellular flagellated organisms arranged in a single layer held by strands of cytoplasm u flagella face outward as the colony spins through water.

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

u Red and Brown Seaweed u 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).

u Brown Algae or Kelp u largest, most complex protist u found in cold, coastal water u Adaptation: air bladder- keep organism near surface to absorb light for photosynthesis u anchored at bottom by “hold fast”

u 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????? u Japanese industry raise algae as a food source. u Many dairy products contain thickening agents such as algin and carrageenan that are made from red and brown algae.