Algae and Heterotrophic Protist - Botany - Lecture Slides, Slides of Botany and Agronomy

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Protista: Algae and

Heterotrophic

Protist

Protista

• diverse group of organisms, comprising those eukaryotes that are not animals, fungi, or plants. They are usually treated as the kingdom Protista

Algae

• regarded as simple plants, they actually span more than one domain, including both Eukaryota and Bacteria ( see Blue- green algae ), as well as more than one kingdom, including plants and protists, the latter being traditionally considered more animal-like ( see Protozoa ).

• All lack leaves, roots, flowers, seeds and other organ structures that characterize higher plants (vascular plants).

• far more common in moist, tropical regions than dry ones, because algae lack vascular tissues and other adaptations to live on land.
• Algae can endure dryness and other conditions in symbiosis with a fungus as lichen.

Role in Aquatic Ecology

• Microscopic forms that live suspended in the water column — called phytoplankton — provide the food base for most marine food chains.

Rocky shores

• Seaweeds
• Members of red, brown and green algae
• At low tides can see distinct layers that can withstand large fluctuations of humidity, temperature, salinity and light

Offshore

• Beyond the zone of waves massive brown kelps form forest
• Provide shelter for diverse fish and invertebrate animals

Protista: Algae and Heterotrophic

Protists

• Dinoflagellates : Phylum Dinophyta
• Euglenoids: Phylum Euglenophyta
• Cryptomonads: Phylum Cryptophyta
• Haptophytes: Phylum Haptophyta
• The Heterokonts- oomycetes, diatoms, pyhaeophyta
• Red Algae: Phylum Rhodophyta
• Green Algae: Phylum Chlorophyta
• The Slime Molds

Algae and “The Carbon Cycle”

• Algae are able to transform carbon dioxide into carbohydrates or intocalcium carbonate
• Today phytoplankton absorb about One-half of all the Carbon dioxide thatresults from human activities
• White cliffs of Dover- calcium carbon deposits “CO2 drawdown” effect

Dinoflagellates: Phylum Dinophyta

• Molecular systematic data- Related to ciliated protozoa such as Paramecium and Vorticella
• Unicellular biflagellates
• Marine and freshwater
• Some dinoflagellates are nonmotile
• Reproduction- longitudinal cell division

Symbiotic forms

• Zooxanthellae- responsible for the photosynthetic productivity that makes possible the growth of coral reefs in tropical waters

Dinoflagellates produce toxic or

bioluminescent compounds

• Toxic glycoside released by activated dinoflagellate cysts
• Paralyze the respiratory tract, dinoflagellates feed on fish then return to cyst stage