Brown Algae Phaeophytes

Brown Algae

Brown Algae Nearly all multicellular marine organisms. Commonly referred to as seaweeds. They have cell walls made of cellulose and alginic acid. Large flat fronds that are useful for withstanding tidal forces.

Brown Algae They have holdfasts at their bases that prevent them from being washed out to sea. They form the kelp forests off the coast of Northern California. It is the only multicellular protist that has well-differentiated tissues: used to carry nutrients through the large fronds.

Dinoflagellates

Dinoflagellates Unicellular Photosynthetic Mostly marine Their protective coats are made of stiff cellulose plates Identified as a group by the presence of two flagellae They are extremely numerous and form an important food source for small marine animals Their reproduction is usually cell division even though they are capable of sexual reproduction

Dinoflagellates In certain conditions they can increase rapidly in population and form a red tide. That big of a population produce toxins that can kill fish poison people who eat shellfish that have fed on algae. Some species of Dinoflagellates are symbiotic, living in bodies of invertebrates such as sea anemones, molluscs and corals called zooxanthellae which lack the characteristic cellulose pates of this phylum This symbiotic relationship is the main reason for the high productivity of coral reefs in nutrient poor waters

Dinoflagellates

Red Algae

Red Algae are delicate, muticellular seaweed found mostly in warm seawaters. They are hard and crusty due to calcium carbonate deposits by species called coralline.

Red algae get their colour because their pigments absorb green, blue and violet light efficiently. Since these light rays penetrate the deepest past the water’s surface, red algae has the ability to grow at deeper depths than other types of algae.

Red algae is very important to sea life Red algae is very important to sea life. Red algae and coral animals together help build coral reefs. Some species of red algae contain material in their cell walls that is the source of agar.

Euglenoids Kingdom Protista Small and unicellular freshwater organisms They have two flagellae (one usually longer) Classified among plant like protists Over half do not have chloroplasts and are heterotrophs

Information cont’d Euglenoids with chloroplasts raised without light loose them. They ingest or absorb food These algae can be autotrophic or heterotrophic

Euglenoids These are Euglenoids.

Fun Fact “Euglenoids have a red, light- sensitive structure called an eye spot. This structure helps Euglena orient themselves towards areas of bright light so photosynthesis can occur.”

DIATOMS

DIATOMS Diatoms are unicellular algae found in oceans Diatoms are one of the biggest components of plankton Diatoms are a major food resource at the base of marine and freshwater food webs They are also a major source of oxygen

DIATOMS Diatoms have rigid cell wells with an outer layer of silica They look like small jewel boxes Diatom skeleton is divided into two part one epitheca and the other hypotheca. Both of these are made out of two parts. The valve and the flattened plate.

DIATOMS During asexual reproduction, they spilt in two, then grows a new half to fit inside the old one The rigid cell wall cannot grow once formed, so every generation of diatoms is smaller then the one before Reduction in size continues until they reproduce sexually, producing a zygote that grows to original size, creating a new cell wall

Green Algae

Green Algae What is Green Algae? Green algae is the most plant-like of the algae They share the same types of chlorophyll and same colour as most land plants. Like plants, their cell walls contain cellulose and they store food reserves in the form of starch.

Green Algae Where they live: Most commonly found in freshwater and damp places on land. Some are known to live in the wet fur of tropical rainforest’s tree sloths. Ulva, a common marine algae, can be found attached to exposed rocks during low time.

Green Algae - Properties Some are unicellular Some are colonial Some form filaments Others are multicellular Green Algae can produce both sexually and asexually Asexual reproduction, the cell divides to form flagellated spores that resemble the parent Chlamydomonas can also reproduce sexually forming gametes of two different types that fuse to form a zygote. This occurs during unfavorable conditions

Green Algae - Examples The Chlamydomonas, Ulva, and Volvox are three of the most common Green Algae. Algae, like the Ulva, can grow to be one metre in length and produce spores with flagellae the flagellae helps them swim. Algae, like the Chlamydomanas, have what is called an eye-spot this helps it swim towards light and conduct photosynthesis. A Volox colony is composed of hundreds of flagellated cells arranged in a single layer - This forms a hollow ball-shaped structure