Origin of Eukaryotic cell Endosymbiotic theory Classification of
Origin of Eukaryotic cell • Endosymbiotic theory
Classification of domain Eukarya? 1) Name all the kingdoms in the domain Eukarya? Molecular phylogeny and concept of molecular clock
Classification of domain Eukarya? LECA (Last eukaryotic common ancestor)
Classification of domain Eukarya? Conclusion: • All protoctists are not members of a single kingdom • Protoctists are not monophyletic in their origin LECA (Last eukaryotic common ancestor) • Eukryotes classified into supergroups
Tradicional classification of Protoctists On what is based above mentioned classification?
Classification of algae – autotrophic protoctista Mostly based on: • Pigmentation • Nature of cell wall components • Nature of reserve food Six divisions: 1. 2. 3. 4. 5. 6. Golden algae (Chrysophyta) Dinoflagellates (Pyrrophyta) Euglenids (Euglenophyta) Green algae (Chlorophyta) Brown algae (Phaeophyta) Red algae (Rhodophytes)
General characteristics Habitat: • wide range of habitats – water (aquatic algae), land (terrestrial algae), epiphytes, extreme conditions • Aquatic algae – planctonic, benthic
Habitat: • Aerophytes • Halophytic algae • Parasitic algae • Symbiotic • Terrestrial • Thermophytic Algae are of universal occurrence!
Thallus organization: • unicellular, colonial, multicellular • microscopic and macroscopic in size Micromonas pusilla (1 µm), kelp (60+ m) • motile, non-motile
Reproduction: • asexual – budding, cell division (fission), fragmentation, spores (highly variable)
Reproduction: • sexual – gametes zygote Depending on the structure and behaviour of fusing gametes: • • • Isogamy Anisogamy Oogamy
Alteration of generations
Divisions Chief (main) pigment Accessory pigments Food reserve Cell wall You will fill in the table after we cover each of the groups
Beneficial Aspects of Algae • • • Food for humans Food for invertebrates and fishes in mariculture Animal feed Soil fertilizers and conditioners in agriculture Treatment of waste water Diatomaceous earth (diatoms) Chalk deposits Phycocolloids (agar, carrageenan from red algae; alginates from brown algae) Drugs Model system for research Phycobiliproteins for fluorescence microscopy
Detrimental Aspects of Algae • • • Blooms of freshwater algae Red tides and marine blooms Toxins accumulated in food chains Damage to cave paintings, frescoes, and other works of art Fouling of ships and other submerged surfaces Fouling of the shells of commercially important bivalves
Euglenoids
Dinoflagellates - Red tide - Bioluminiscence
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