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Aquatic Plants –
Green, Red, and Brown Algae
www.onacd.ca
Green Algae
6000 species
single cells
colonies
long filaments.
Chlamydomonas
Spirogyra
Ulva
Green Algae
aquatic (freshwater or marine) or terrestrial (near lots of H2O)
form symbiotic relationships with fungi to form lichens.
Algal bloom
Volvox
Caulerpa –
an invasive
seaweed
Characteristics of Green Algae
• chlorophyll a & b (green
color)
• Mitochondria with flat
cristae
• Some have flagella for
movement
• cell walls with cellulose
Characteristics of Green Algae
• Asexual reproduction:
by fission,
fragmentation or
zoospores (motile
spores)
• Sexual reproduction:
go through 2
different life stages
using a method called
“alternation of
generations
Alternation of Generations
A 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
– Produces spores by meiosis
Stage 2
• Haploid (1N – each cell has one set of chromosomes)
– Called the gametophyte
– Produces gametes by mitosis
– Gametes fuse to form a sporophyte by fertilization
Chlamydomonas
Characteristics
• 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 Cycle
Take 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
• definite alternation of
generations to reproduce
• Gametes are freeswimming and a zygote
is formed in the water
Ulva Life Cycle
MITOSIS
Mitosis: 1 cell
becoming 2 equal
diploid cells
Meiosis: 1 cell
becoming 4
haploid cells
(gametes)
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
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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&pla
ynext=1&playnext_from=PL&index=11 killer algae #3
http://www.youtube.com/watch?v=9PMUHQo2qaU&feature=PlayList&p=D6BA6B6F9097A4F5&in
dex=12 killer algae #4
http://www.youtube.com/watch?v=EsNJKvNhCP8&feature=PlayList&p=D6BA6B6F9097A4F5&ind
ex=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&pl
aynext=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&pla
ynext=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=jcWYAn
mm-QE&feature=related kelp forest
• http://www.youtube.com/watch?v=v_aSl3i
L7rM 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.