Ch. 28 The Origins of Eukaryotic Diversity
Introduction to Protists• Eukaryotes.• Most diverse• Most are unicellular, some
colonial and multicellular species.
• Simplest eukaryotic organisms.• Many protists are exceedingly
complex – the most elaborate of all cells.
• Aquatic• Asexual/sexual reproduction
Protists
• Aerobic in their metabolism, using mitochondria for cellular respiration.
• Phototrophs with chloroplasts.• Heterotrophs that absorb organic materials
or ingest larger food particles.• Mixotrophs: combo of photo and
heterotrophic nutrition
Early EuK Origin• proK small size, limit space for genes.
• Limits metabolic activity
• Evolution of ProK:– Multi-cellular proK– Complex communities– Compartmentalization
• Endosymbiosis– Mitochiondria– Plastids (chloroplasts)
• Produces a chimera
Secondary Endosymbiosis
• Diversity of Algae
• Endosymbiosis occurs twice
Diplomonadida & Parabasala
• No mitochondria• Multiple flagella
– Giardia lambia
– Trichomonas vaginalis
Euglenozoa
• Eugleniods and Kinetoplastids• Single mitochondria• Types
– Trypanosoma (African sleeping sickness)
– Euglena
Alveolata• Parasitic
• Cilia
• Types– Dinoflagellates: phytoplankton
• Pfiesteria piscicidia: carnivorous, blooms, toxins stuns
– Apicomplexans• Plasmodium: Produces sporozoite
– Ciliophora• Conjugation
Stramenopila
• Heterotrophic/photosynthetic• Oomycota• Diatoms• Golden, Brown Algae (seaweed)
Alteration of Generations
• Alteration of haploid/diploid that are multicellular• Sporophyte = diploid individual• Gametophyte = haploid individual• Heteromorphic = sporophyte/gametophyte
structurally different• Isomorphic = s/g look alike, differ in chromosome
number
Algae• Rhodophyta: red algae
– No flagella
– Phycobilins (red pigment) in plastids
• Chlorophyta: green algae– Green pigment
– Lichens
– Biflagellated
– Many colonial, multicellular
Movement and Feeding
• Heterotrophs, symbiotic• Rhizopoda: amoebas
– Pseudopodia
• Actinopoda: Heliozoans– Axopodia
• Foraminifera– Marine
– Porous shell
Mycetozoa• Slime Molds• Plasmodium Slime
Molds:• Cellular Slime Molds: