2. Marine algae is called “seaweed”
There are three main
groups of salt water
seaweeds
Brown algae
Green algae
Red algae
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3. Structures of brown algae
Thallus (pl. thalli)
multicellular bodies usually flattened
Holdfast
Stipe
Blades
Bladder (float)
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5. Giant kelp Macrocystis pyrifera
May grow up to 300 feet
Brown pigments called
fucoxanthin with
chlorophyll and other
pigments
Giant stalks have stem
like stipes to help support
them and grow towards
the sunlight
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6. Fucus rockweed we love to pop
Separate male and female
thalli are produced
Both sexes may develop
on the same thallus
Puffy fertile areas call
receptacles develop at the
tips of the branches of the
thallus
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8. Gametangia ….. (algae reproductive structures
Within every receptacle are dotted pores (visible
to the naked eye) that open into special spherical
hollow chambers called conceptacles
Within a conceptacle gametangia (cell structures
where gametes are produced) form
Eight eggs are formed in the oogonium (female
gametangium)
Meiosis happens (the process of two successive nuclear divisions
through which segregation of genes occurs and a single diploid (2n) cell
becomes four haploid (n) cells )
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9. Feathery red Polysiphonia has three types of
thallus, male , female and tetrasporophyte.
Meiosis happens on the
tetrasporophyte
Male thallus produces
spermatangium , non
motile (can’t move on its
own)
Female thallus , has a
carpogonia, which
produces one egg, non
motile too
Ocean waters transport the
two for fertilization
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10. the Zygotes journey
The pericarp (an urn shaped body, of the outer part of which the female
gametophyte thallus) is the destination
The zygote begins to divide and eventually forms clusters of
carposporangia
The pericarp and carposporangia combine to form
the cystocarp
Diploid asexual spores called carpospores are
produced and released into the ocean
Eventually fasten themselves to bottom rock or
hull of a boat and grow into a tetrasporophyte
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12. Completing the life cycle of Phylum
Rhodophyta
The terosporangium
undergo meiosis
They develop into four
haploid tetraspores
Tetraspores germinate
Then develop into male
gametophytes or female
gametophytes
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13. Super foods from seaweeds
are packed with vitamins, antioxidants and minerals we need
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14. Red algae Rhodophyta
Sulfated polysaccharides
are found in some red
algae
These complex
carbohydrates contain
sulfate
Improve auto immune
system functions
Have been found to
stimulate anti tumor agents
our bodies produce
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15. Green algae Chlorophyta
Important part of the
plankton community
Free floating often
The smallest eukaryotic
cell known is a
Chlorophyta called
Micromonas
Can camouflage animals
Can reproduce sexually
and asexually
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16. Brown algae Phaeophyceae
Can be olive green to
brown color
Many are large algae
Most are marine (salt water
algae)
Giant kelp
Fucus rockweed
Sargassum seaweed
belongs to brown algae
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17. AGAR
Agar was discovered by
accident in Japan when some
extracted seaweed was left
outside the door of a mountain
inn and froze overnight. On
thawing the innkeeper
discovered that the impurities
were carried away and with
repeated thawing and freezing
—a process still used today for
the most valued food agars—a
quality product with the mouth
feel that appeals to Japanese
tastes. This is called kanten in
Japan and has become so
popular recently that some
restaurants serve nothing but
kanten in all sorts of guises for
the diet-conscious young
executive
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