Seaweeds

Seaweeds - Seaweeds or Macroalgae are the large primary...

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Unformatted text preview: Seaweeds or Macroalgae are the large primary producers of the sea. sea. Though more complex than the Though unicellular algae, seaweeds still lack the complex structures found in land plants. found General Structure General This is a very diverse group, and although they lack true leaves, stems, and roots, they have a few common structures. The complete body is called the thallus no matter thallus the growth form. the Usually, all regions Usually, of the thallus can photosynthesize. photosynthesize. The leaf-like flattened portions are called blades. blades The blades are The usually the main photosynthetic region.These are not true leaves because they lack Most seaweeds have gas-filled bladders or floats bladders floats that will help them maximize sunlight exposure. Sometime these floats contain carbon monoxide. carbon Some seaweeds have a stem-like structure called the stipe. This stipe This structure is not found on all seaweeds. seaweeds. The stipe provides stipe support and can be long and tough, as in the Giant Kelp. Giant The stipe also The stipe allows a place for the attachment of the blades. the A holdfast is a holdfast root-like structure that holds the seaweed to the bottom. This structure does not aid in gathering nutrients. nutrients. The holdfast does not penetrate through sand or mud, so like this Sea Palm, most Sea most macroalgae are only found on hard sediments. hard Types of Types Macroalgae The are three types of macroalgae The Green and Brown Red Green Algae Green About 700 of the 7,000 species of green algae are marine. Of those, few are multicellular. multicellular. Green Algae Green Green algae can be very common where the salinities vary a lot. ( Bays, Estuaries, Tide Pools) Pools) Green Algae Green They are usually bright green because the chlorophyll is not masked by other pigments. other Green Algae Green Green algae have a simple thallus when compared to red and brown algae. algae. Green Algae Green Many forms are filamentous or form paper-thin sheets. sheets. Green Algae Green Others form spongy fingers as in this example of Dead Man’s Fingers. Fingers Brown Algae Brown Almost all species of brown algae are marine. The best know and the most complex are the kelps. the Brown Algae Brown Color varies from olive green to dark brown because there are many yellow-brown pigments that mask the color of chlorophyll. chlorophyll. Brown Algae Brown Besides the well known kelps, Sargasso weed is also a well known brown algae. algae. Brown Algae Brown Sargasso weed often forms into large mats in the mid Atlantic where unique animals and communities can be found. can Brown Algae Brown Notice anything here? here? Can you see the Can Sargassum Angler Fish? Angler Red Algae Red There are more species of marine red algae than green or brown. green Most are actually Most red! red! Red Algae Red Some red algae have calcium carbonate within their cell walls. their These, help form These, coral reefs. coral How about a quick quiz? How 1. The entire body of the The seaweed is called the _____. seaweed 2. What is another name for What seaweeds? seaweeds? 3. Name the 3 types of Name seaweeds. seaweeds. 4. What is the stem-like structure called? structure 5. Which type of seaweed can 5. be important in the formation of a coral reef? of Answers Answers 1. Macroalgae 2. Thallus 3. Red, Green, and Brown 4. Stipe 5. Red ...
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This note was uploaded on 11/09/2011 for the course BIO 110 taught by Professor Harmon during the Winter '11 term at BYU.

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