Algae

• Nearly 75% of the world’s oxygen produced by algae • One of the major food source of marine ecosystems • Eukaryotic, photosynthetic (autotrophs)

STRUCTURE Four types of algae Unicellular Colonial Filamentous multicellular

THE TYPE OF ALGAE Unicellular Colonial multicellular Filamentous

CLASSIFICATION OF ALGAE SEVEN PHYLUM BASED ON COLOR TYPE OF CHLOROPHYLL FOOD-STORAGE SUBSTANCE CELL WALL COMPOSITION

Algal groups In today’s lab, we will look at algal groups:

Chlorophyta: Green Algae • Mostly found in fresh water • Contain chlorophylls a and b • Store energy as starch (carbohydrate) • Cell walls made of cellulose

Genus: Chlamydomonas Motile, unicellular algae

Genus: Spirogyra Filamentous

Genus: Volvox Consists of many Chlamydomonas-like cells bound in a colony Each cell has two flagella

Phaeophyta: Brown Algae • marine algae • No unicellular or colonial forms • Contain chlorophyll c and brown pigment fucoxanthin • Range in size from microscopic to over 50 meters long

Genus: Fucus • Also called “rockweed” • Typically attaches to rocks • Outer surface covered by gelatinous sheath

• Tips of branches (called conceptacles) may be swollen and contain reproductive structures – oogonia (female, produce eggs) and antheridia (male, produce sperm)

Rhodophyta: Red Algae • “Red algae” • Contain chlorophyll d and red pigments (phycobilins) • Mainly multicellular • Typically in warm marine water • Can be attached, free-floating, filamentous, or parenchymatous (fleshy)

Chrysophyta “Diatoms” • Unicellular • Contain chlorophylls a and c, as well as xanthophyll pigments (golden-brown) • Have hard cell wall made of silicon dioxide

Diatoms can be: • Pennate (bilateral symmetry) Or • Centrate (round, radial symmetry)

Euglenophyta • Unicellular • Motile (two flagella) • Contain chlorophylls a and b • Mainly freshwater algae • Main cell wall component: protein (flexible) • Asexual reproduction

Genus Euglena Unicellular