multicellular primary producers: seaweeds and plants video
TRANSCRIPT
MULTICELLULAR PRIMARY PRODUCERS: SEAWEEDS AND PLANTS
video
Multicellular algae- the seaweeds
Macrophytes or macroalgae Multicellular Eukaryotic
General structure Lack true leaves, stems and roots Complete body called a thallus
Blades- leaf-like, flattened portion; main photosynthetic regions; don’t have veins Pneumatocysts- gas-filled bladders; keep blades
close to the surface Stipe- stem-like structure where blades
originate Holdfast- looks like roots; attaches the thallus
to the bottom
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TYPES OF SEAWEEDS
Three types Green algae- Brown algae Red algae
GREEN ALGAE
Phylum Chlorophyta Live in fresh and terrestrial
environments Only 10% of 7000 species marine Believe land plants evolved from green
algae may be filamentous
Enteromorpha- thin thallus is a hollow tube; in polluted areas
Ulva latica or sea lettuce- common where fresh water meets thesea
Valonia- forms large spheres or spherical clustersin the tropics and subtropics
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Caulerpa- has thin filaments or tubes
Codium- dead man’s fingers Codium setchelli
Some green algae are calcareous- they deposit calcium carbonate to help build the coral reef
Halimeda
BROWN ALGAE
Color varies from olive green to dark brown due to pigments called fucoxanthin
1500 known species Dominant primary producers on
temperate and polar rocky coasts Largest seaweeds
Usually exposed at low tide on rocky shores
Thick, leathery thalli can stand exposure to air
Some known as rockweeds or wracks
Fucus
Kelp- most complex and largest of all brown algae
Found below the low tide level in temperate and sub-polar latititudes
Some consist of a single large blade which may be harvested for food
Laminaria
Laminaria
Macrocystis- larges of the kelps Can reach 100m Form kelp beds or forests
RED ALGAE
More abundant Have red pigments called phycoobilins 4000 species mostly marine Live in shallow water Some are parasites of other seaweeds Some are heterotrophs Most are filamentous
Gigartina
Coralline algae- red algae that deposit calcium carbonate within their cell walls; some help with the development of coral reefs
LIFE HISTORY OF SEAWEEDS
Asexual is common fragments of thallmus can grow into new
individuals Spores (cells that are specialized for
dispersal) Zoospores= spores with flagella for
movement
Sexual Reproduction- production of gametes
4 basic types of life histories Type A- 2 types of thalli; most common
form; 2n (diploid) sporophyte produces haploid spores that are motile which eventually divide and produce the second kind of thallus, a haploid gametophyte
SUMMARY Algae produces most of the oxygen that we breathe. Multicellular algae, or seaweed, is classified in three colors: red, green, and brown. Unicellular Algae is broken down into two groups Diatoms and Dinoflagellates. All of these organisms have special and unique adaptations that enable them to
survive their environments. Plankton is a combination of uni and multicellular algae and forms the basis of all
life in the ocean.