Aquatic Plants – Green, Red, and Brown Algae

www.onacd.ca

Green Algae

Chlamydomonas Spirogyra Ulva

6000 species

single cells

colonies

long filaments.

Green Algae

Algal bloom Volvox

Caulerpa – an invasive seaweed

aquatic (freshwater or marine) or terrestrial

form symbiotic relationships with fungi to form lichens.

Characteristics of Green Algae• chlorophyll a & b (green

color)

• Some have flagella for movement

• cell walls with cellulose

Characteristics of Green Algae

• Sexual reproduction: go through 2 different life stages using a method called “alternation of generations

• Asexual reproduction: by fission, fragmentation or zoospores (motile spores)

Alternation of GenerationsA life cycle in which there are two distinct life stages

that occur alternately for a species

Stage 1 • Diploid (2N – each cell has two sets of chromosomes)

– Called the sporophyte– Produce gametes (= sex cells = haploid cells) by meiosis

Stage 2• Haploid (1N – each cell has one set of chromosomes)

– Called the gametophyte– Fuse to form a sporophyte (= zygote = diploid cells) by

fertilization

ChlamydomonasCharacteristics• Unicellular• Motile, 2 equal flagella• Occur in stagnant water and

damp soil, fresh water and salt water, even in snow!

• Have a nucleus inside their chloroplast

• Possess two small vacuoles which function to remove waste

• Have a light sensitive, red pigment spot which allows the cells to swim towards light

Chlamydomonas Life CycleTake a good look at the diagram below of the life cycle of Chamydomonas

which is an example of alternation of generations. Note the diploid (2N) and the haploid (1N) stages of its life.

Diploid (2N)

Spirogyra

• Algal cells are joined end to end to form filaments (multicellular)

• Mostly freshwater• Generally free floating• Reproduces asexually by fragmentation and sexually by

conjugation• Does not form gametes,

therefore does not go

through alternation of

generations• Undergo conjugation –

exchange of genetic information

Ulva (sea lettuce)• Multicellular green algae

(looks like a plant)• Lives in marine and

brackish water• Has flat, blade like

leaves called a thallus which is made up of two layers of cells

• Gametes are free-swimming and a zygote is formed in the water

Ulva Life Cycle

Mitosis: 1 cell becoming 2 equal diploid cells

Meiosis: 1 cell becoming 4 haploid cells (gametes)

MITOSIS

Lichens • Can be formed by a

symbiotic relationship between green algae and a fungus

• The fungus provides the algae with water and minerals that it absorbs from whatever it is growing on and protects the algae by retaining water and serving as a larger capture area for minerals and nutrients

• The algal cells uses minerals and water to make food for the fungus and itself

Stained slide

Youtube• http://www.youtube.com/watch?v=OHRPfkCeXHg&feature=related killer algae #1

• http://www.youtube.com/watch?v=gE3d3o1nvt8&feature=related killer algae #2

• http://www.youtube.com/watch?v=hkrWSpNY2B4&feature=PlayList&p=D6BA6B6F9097A4F5&playnext=1&playnext_from=PL&index=11 killer algae #3

• http://www.youtube.com/watch?v=9PMUHQo2qaU&feature=PlayList&p=D6BA6B6F9097A4F5&index=12 killer algae #4

• http://www.youtube.com/watch?v=EsNJKvNhCP8&feature=PlayList&p=D6BA6B6F9097A4F5&index=13 killer algae #5

• http://www.youtube.com/watch?v=b8ugGN9lCu0&feature=related volvox

• http://www.youtube.com/watch?v=NzV_tE75SmA&feature=related chlamydomonas

• http://www.youtube.com/watch?v=LsU6xRvGl8k algae lady on Vancouver Island

• http://www.youtube.com/watch?v=8edk6nGMwMs&feature=PlayList&p=E189ADC6E5940F0F&playnext=1&playnext_from=PL&index=2 elodea cytoplasmic streaming– an aquatic angiosperm not an algae

• http://www.youtube.com/watch?v=F_CRQYw9nvc&feature=PlayList&p=D6BA6B6F9097A4F5&playnext=1&playnext_from=PL&index=1 algae as a biofuel

• http://www.youtube.com/watch?v=1MeIgaRfyD4 algae as biofuel

• http://www.youtube.com/watch?v=YO3Gg3YfJ84&feature=related algal blooms are centre stage

Red Algae - Rhodophyta

• Red algae are red because of the presence of the pigment phycoerythrin; this pigment reflects red light and absorbs blue light. Because blue light penetrates water to a greater depth than light of longer wavelengths, these pigments allow red algae to photosynthesize and live at somewhat greater depths than most other "algae".

Importance of red algae

• Nori sushi – high vitamin and protein content – relative simplicity of cultivation, which began in Japan

more than 300 years ago.

• Agar– Bacterial growth medium

• Carrageenan

-food additive/thickener

Importance of red algae

• important in the formation of tropical reefs, – in some Pacific atolls, red algae have

contributed far more to reef structure than other organisms, even more than corals.

– called coralline algae, because they secrete a hard shell of carbonate around themselves, in much the same way that corals do.

• Nori – red algae used for food/sushi

• Agar agar – red algae used for food and bacterial cultures

• Carrageenan – red algae used as a food additive and thickener

• Coralline algae

Brown algae - phaeophyta

• May reach over 30 meters in length.

• Almost all are marine.

• Pigments– chlorophyll c and fucoxanthin.

Brown algae - phaeophyta

• Blades (analogous to leaves) • branch from the stipe, or stalk

• Receptacles– form on the surface of the blades– structures in which the gametes are produced.

• Sargassum – brown algae– Pelagic (free-floating)

• Fucus – also called rockweed– Attached to

rocks via stipes

Youtube

• http://www.youtube.com/watch?v=jcWYAnmm-QE&feature=related kelp forest

• http://www.youtube.com/watch?v=v_aSl3iL7rM cousteau kelp forest

5 Really Bad Algae Jokes…..

Why did the algae and the fungus get married? They took a lichen to each other.

Why do many algae couples drift apart?They prefer planktonic relationships.

Why couldn't the algae keep a girlfriend?He wasn't a fungi.

Why did the algae get pulled over on his way to the pond?He was chloro-plastered.

Why did the algae fail math?He divided when multiplying.He didn’t know algae-bra.