48 terms

Ch. 6: Multicellular Primary Producers: Seaweeds & Plants

From Marine Biology textbook (by Peter Castro): pg. 102 - 114
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seaweed = macrophytes = macroalgaes
-type of multicellular eukaryotic marine algae
-promote coral reef growth
thallus (plural: thalli)
entire seaweed plant except base
blade
leaf - like objects, sprout from stipe; NOT a real leaf because they lack veins & top & bottom are identical
pneumatocysts
tiny gas-filled sac at base of blade; makes blade float --> maximize blade's sun exposure --> maximizes photosynthesis

filled with CO
stipe
seaweed stem
holdfast
anchors thallus down; has no other functions and does not penetrate ground
types of seaweeds
green, brown, & red algae
carotenoid
-aids in photosynthesis
-colorless
green algae
-phylum: Chlorophyta
-descendants of plants
-contains chlorophyll a & b, carotenoids
-green - chlorophyll is only colorful pigment
-food reserve: starch
-cell wall composed of : cellulose, calcium carbonate in some
calcareous green algae
thallus = numerous segments with calcium carbonate deposits
brown algae
-phylum: Phaeophyta
-eukaryotic, multicellular
-have chorophyll a & c, carotenoids (ie fucoxanthin)
-can be dark green or dark brown - chlorophyll overpowered by fucoxanthin
-food reserve; laminarin, oil
-cell wall made of cellulose, alginates
-largest & most structurally complex seaweeds
fucoxanthin
type of yellow-brown pigment, common in brown algae
rockweeds = wracks
brown algae that grow in intertidal shores; lack pneumatocysts
sargasso weed (Sargassum).
-usually grow on rocks
-may float offshore in huge masses
-common in Gulf of Mexico & in Sargasso Sea
Sargasso Sea
-area in the Atlantic, north of the West Indies
-contains a lot of sargasso weed.
kelp
-most complex and largest brown algae
-in temperature & subpolar regions
-grow in shallow water
-edible
kelp bed = kelp forest
-area of dense kelp grow; steps grow quickly
-in cold parts of Pacific
red algae
-phylum: Rhodophyta
-eukaryotic, multicellular
-contain chlorophyll a, phycobilins, carotenoids
-usually red - phycobilins overpower chlorophyll
-color also depends on light exposure; can be black
-food reserve: starch
-cell wall composed of agar, carrageenan, cellulose, calcium carbonate sometimes
-male gametes lack flagella - immobile - released from thallus in slime
phycobilin
type of red pigment, common in red algae
coralline algae
-red algae
-have calcium carbonate deposits in their cell walls
-are different shades of red
spores
-aid in seaweed reproduction (asexual)
-cells that travel from source; persist through harmful conditions
-no flagella
-have cell walls
zoospores
-aid in seaweed reproduction (asexual)
-cells that travel from source; persist through harmful conditions
-possess flagella (tails) to move
-no cell walls
gametes
sex cells - sperm & egg
mitosis
-production of identical body cells
meiosis
-production of sex cells
haploid (n) cell
# of chromosomes in cell is 1/2 the # in body cells of same organism
sporophyte generation
-made through meiosis
-produces mobile haploid spores, not gametes
-spores develop into gametophytes
gametophyte generation
-produces mobile haploid gametes
-2 gametes combine to make a zygote or carposporophyte (both diploid)
kelp reproduction
-one kelp organism releases female & male gametes; eggs are immobile & most sperm move with flagella
-in one kelp organism, one thallus can release both gametes OR male/female thalli are separate
alteration of two generations
-final organism formed from 2 predecessors
-in kelp, predecessors are spores & gametes
alteration of three generations
-final organism formed from 3 predecessors
-in kelp, predecessors are spores & gametes & carpospores
carposporophyte generation
-diploid
-results from gamete fusion
-produce carpospores
Carpospores
-diploid
-produced by carposporophyte generation
-develop into sporophytes
no alteration of generations
thallus produces gametes & they combine to make a zygote
mariculture
seaweed farming
phycocolloids
-gelatinous chemicals produced by seaweed
-used in food processing
-valuable because of ability to form gel even at low concentrations
algin
-type of phycocolloid
-made by kelp
-used as a stabilizer, emulsifier
-used in baking, dairy, drug, chemical, textile, paint, cosmetic industries
carrageenan
-type of phycocolloid
-made by red algae
-used as an emulsifier
-used in dairy industry & in processed food
agar
-type of phycocolloid
-made by red algae
-used to form gel
-used in protein distribution, drug, cosmetic industries, also in scientific research
commercial uses of seaweed
-phycocolloids
-fertilizer
-additive in animal feed
-to dress wounds
-reduce soil acidity
-food
flowering plants (angiosperms)
-kingdom: Plantae; phylum: Magnoliophyta
-most live on land
-eukaryotic, multicellular
-contain chlorophyll a & b, carotenoids
-food reserve: starch
-cell wall made of cellulose
seagrass
-evolved from land plants
-not grass
-flowering plant, lives in seawater
pollen
-released by flowering plants
-contains sperm
-thread-like in seagrasses
cordgrass
-not truly a marine plant - just a land plant tolerant of salt water
-never fully submerged
-true grass
-flowering plant
halophytes
salt-tolerant plants
estuarine environment
habitat in which freshwater & saltwater mix
mangroves
-trees that live on tropical and subtropical shores
-land plants that tolerate saltwater
-leaves are thick to combat water loss
dangers posed by salt marshes to their organisms
-sediment is soft
-sediment is poor in oxygen
-organisms lose a lot of water