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: