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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.