ALGAEJhia Anjela D. Rivera1

1BS Biology Graduate, Department of Biology, College of Science, Polytechnic University of the Philippines

ALGAE

• Very large and diverse group of eukaryotic organism• Single-celled forms to complex multicellular form• Plant-like organisms that are usually photosynthetic and aquatic

• Do not have true roots, stems, leaves, vascular tissue• Have simple reproductive structures• Have chlorophyll, (photosynthesis)

STRUCTURE

•Thallus•Four types of algae•Unicellular•Colonial•Filamentous (forming long filaments of attached cells)•Parenchymatous (cells forming a thalluswith partial differentiation of tissues)

IDENTIFY THE STRUCTURE

THALLUS

• a plant body that lacks differentiation into distinct parts (as stem, leaves, and roots)

SOME UNICELLULAR ALGAE (PHYTOPLANKTON)

Scenedesmus sp. Chlorella sp. Pediastrum sp.

RHODOPHYTA• with about 400 genera• mostly marine with only a few known freshwater genera• Most are found in tropical areas where they occur at great

depths or along intertidal regions• color varies greatly depending on the amount of pigments• range from shades of green, red-brown, bright red, blue, and

purple-blue to black• carotenes and xanthophylls• Contains phycobilin pigment that masks the chlorophylls • Phycobilin pigment contains (red phycoerthyrin and blue

phycocyanin)

RHODOPHYTA

Porphyra perforata Polysiphonia nigra

CHLOROPHYTA

• mainly freshwater plants, but also occur in saltwater, in soil, on tree bark, and on snow.

• unicellular,• colonial, filamentous, membranous (resembling) leaves), and tubular

• well-organized chloroplasts

CHLOROPHYTA

Scenedesmus sp.

Halimeda sp.Chlorella sp.

Acetabulum sp.

PHAEOPHYTA

• mainly marine• live along cooler coastal, intertidal areas, forming large beds of brown seaweed

• violaxanthin and fucoxanthin, source of the brown color

PHAEOPHYTA

Sargassum sp.Ectocarpus sp.

IMPORTANT USES OF ALGAE

• Agar - a gelatinous substance derived from red algae (bacteria and fungi culture)

• Alginates - extracted from brown algae (gelling agents in food, to medical dressing)

• Energy source - ↑biomass = ↑ biofuel• Fertilizer (lifestock feed, soil conditioners)• Nutrition - source of food & vitamins including: A, B1, B2, B6, niacin and C, and are rich in iodine, potassium, iron, magnesium and calcium)

IMPORTANT USES OF ALGAE

• Pollution control & Bioremediation• Wastewater treatment

• Sewage• Runoff water from farms

• Source of pigments (alternative to chemical dyes and coloring agents)

• Stabilizing agents (carrageenan = stabilizer in milk and meat products)

Na-gets?

QUIZ 2

1-5. Compare and contrast red, brown and green algae.6-9. Enumerate the different structural types of algae.10-15. Give at least 6 important uses of algae.16-20. Differentiate a terrestrial plant to an algae, in terms of external morphology.