Exercise_25_Survey_of_Protista-Algae

Introduction

• Overview of the subject matter regarding Protista and Algae.

Domain Eukarya

• Kingdoms in Eukarya:

  • Fungi: Cell walls made of chitin; heterotrophic.

  • Plantae: Multicellular autotrophs with cell walls.

  • Animalia: Multicellular heterotrophs with no cell walls.

  • Protista: A catch-all kingdom characterized by a diverse array of organisms.

• Common Characteristics of Protists:

  • Primarily live in moist habitats.

  • Mostly microscopic in size.

Protists and Protozoans

• Protozoans:

  • Defined as "Primitive Animals".

  • Characteristics include being unicellular and heterotrophic.

  • Protozoa is a subkingdom within Kingdom Protista.

• Distinction Between Protists and Protozoans:

  • Protists encompass both heterotrophic and autotrophic organisms.

Algae

• Definition:

  • Photosynthetic, eukaryotic organisms lacking multicellular sex organs.

• Classification of Algae:

  • Distinguished by their energy storage products, cell wall composition, and colors.

  • Types based on pigment colors include green algae, brown algae, and red algae.

Characteristics of Algae

• General Traits:

  • Photosynthetic protists differentiated by pigments and cellular structure.

  • Fundamental in the food chain and a major oxygen source.

  • Present in freshwater and saltwater.

  • Cell walls typically composed of cellulose.

Morphological Classification of Algae

• Types of Algal Forms:

  • Unicellular: Individual cells.

  • Colonial: Groups of cells that remain together.

  • Filamentous: Chains of cells attached linearly.

  • Shapes: Club-shaped, rod-shaped, spherical.

Phyla of Interest

Unicellular Green Algae

• Phylum Chlorophyta:

  • Represents green algae, sharing traits with land plants.

  • Features include the presence of chlorophyll a and b, and starch storage.

• Common Genera:

  • Chlamydomonas: Found in soils and lakes; unicellular.

  • Phytoplankton included in this category.

  • Filamentous Green Algae found in freshwater—genus Cladophora.

Red Algae

• Phylum Rhodophyta:

  • Adapted to warm-water environments; largest group of algae.

  • Contains chlorophyll a and phycobilins which assist in photosynthesis.

• Common Genera:

  • Polysiphonia: Filamentous red algae.

  • Chondrus: Commonly known as Irish Sea Moss (Chondrus crispus).

Brown Algae

• Phylum Phaeophyta:

  • Typically found in cold-water environments.

  • Rarely found in freshwater.

  • Utilizes chlorophyll c and fucoxanthin, a type of carotenoid.

• Common Genera:

  • Fucus: Known as Bladderwrack (Fucus vesiculosus).

Diatoms

• Single-celled protists known for their silica cell walls.

• Major contributors to Earth's oxygen supply, major phytoplankton in oceans and soils.

• Contain chlorophyll a and c, vital for photosynthesis.

• Important for examining environmental conditions and used to create diatomaceous earth.

Dinoflagellates

• Unicellular flagellated organisms found in freshwater and saltwater environments.

• Many are photosynthetic; some exhibit heterotrophic behavior.

• Known for bioluminescence and the phenomenon of red tide due to rapid reproduction, which can be toxic to marine life.

Euglenoids

• Characterized as single-celled organisms residing in freshwater.

• Can be free-living or parasitic; feeding through phagocytosis.

• Unique because of their pellicle that maintains cell shape, lacking a traditional cell wall.

• Capable of being autotrophic, heterotrophic, or saprophytic.

• Common genus is Euglena.

Importance of Algae

• Green Algae: Key for starch production and storage.

• Red Algae: Source of carrageenan for stabilizing food products and cosmetics.

• Brown Algae: Important as food (such as Kombu) and source of alginic acid used as an emulsifier in food and cosmetic products.