Kingdom Protista Multicellular Algae (Seaweeds) and Kingdom Plantae Notes

Algae: Kingdom Protista Photosynthetic, plant-like Vary in size: microscopic (unicellular) to macroscopic (multicellular) Important primary producers in marine environments

Microscopic Algae

Mulitcellular Algae

Macroalgae Structure Thallus: simple body structure of algae Typically has three parts Holdfast: root-like, anchors algae to substrate Stipe: stem-like; hold up blades, absorbs shock of waves, Blades: leaf-like; site of sexual reproduction Gas bladders (pneumatocyst): gas filled floats used in flotation

Phylum Chlorophyta Also known as Green Algae Can be unicellular or multicellular Live in terrestrial, freshwater and marine environments Contain chlorophyll a and b as the main pigment It is believed that plants evolved from green algae. Calcareous algae play an important role in the formation of coral reefs.

Green Algae http://www.seaslugforum.net/find/halimeda

Phylum Phaeophyta Also known as Brown Algae Multicellular Vary from olive green to dark brown Contains the pigment Fucoxanthin (yellow-brown) in addition to chlorophyll a and c Contains the algae known as Kelp

Brown Algae

Kelp Most complex and largest of all brown algae Areas with high density of kelp are called kelp forests or kelp beds. Most are found in cold, nutrient rich, shallow waters Mainly found on coastlines where upwellings occur.

Sargassum Found in warm water Small, spherical air bladders to keep seaweed floating at the surface. Many organisms live in sargassum and are found no where else. Provides food and shelter for baby sea turtles. Sargasso Sea: North Atlantic

Phylum Rhodophyta Also known as Red Algae More species than green and brown algae combined Contain pigments known as phycobilins (phycocyanin and phycoerythrin) and chlorophyll a Coraline algae are important in coral reef formation

Red Algae

Algae Reproductive Cycle Leafy part of the algae is the thallus The diploid sporophyte thallus produces spores (haploid). Spores have flagella and swim away, once they reach a suitable substrate they develop into a haploid gametophyte thallus. The gametophyte thallus produces gametes (sperm and egg cells) Two gametes fuse to produce a zygote and develop into the next leafy diploid sporophyte

Alternation of Generation Reproductive cycle with the succession of two types of generations: sporophyte generation-asexual and gametophyte generation- sexual Found in some land plants as well.

Alternation of Generation

Importance of Algae Phycocolloids: gelatinous chemicals used in food processing -algin: stabilizer and emulsifier in dairy, processed foods, shampoo, shaving cream, plastics, pesticides, etc…. -carrageenan: emulsifier; gives body to dairy and processed foods -agar: form jellies

Kingdom Plantae Flowering Plants: A.K.A. Angiosperms Phylum Magnoliophyta Dominate the land only a few in the ocean. Only seagrasses are truly marine

Seagrasses Not grasses but members of the lily family Completely submerged, found in shallow subtidal zones Create hiding places for other organisms Underground stems (rhizomes) help stabilize sandy ocean floor Flower underwater and disperse pollen in thread under water 60 species

Seagrass Thalassia Zostera Syringodium

Marsh Grass Grow along the sandy beaches, never completely submerged by water Halophytes: contain salt glands which help them excrete excess salt. Provide habitat for crabs and mussels Help break down industrial pollutants that flow into marshes

Marsh Grass

Mangroves Trees and shrubs adapted to live along tropical and subtropical shores Important producers Offer protection for young organisms Over 80 different species

Mangroves

Mangrove Adaptations Coping with salt: filtering out as much as 90 percent of the salt found in seawater as it enters their roots. Some species excrete salt through glands in their leaves. concentrate salt in older leaves or bark, when the leaves drop or the bark sheds, the stored salt goes with them.

Hoard fresh water:  Like desert plants, mangroves store fresh water in thick succulent leaves. A waxy coating on the leaves of some mangrove species seals in water and minimizes evaporation. Small hairs on the leaves of other species deflect wind and sunlight, which reduces water loss through the tiny openings where gases enter and exit during photosynthesis..

Breathe in a variety of ways:  Some mangroves grow pencil-like roots that stick up out of the dense, wet ground like snorkels. These breathing tubes, called pneumatophores, allow mangroves to cope with daily flooding by the tides. Pneumatophores take in oxygen from the air unless they're clogged or submerged for too long.