orgins of Eukaryotic Diversity (1)

Eukaryotic cells characteristics (1)?

• Nucleus that contains DNA

• Membrane-bound organelles (mitochondria, ER, Golgi, etc)

Eukaryotic cells characteristics (2)?

• 80s ribosomes

• Cytoskeleton

• Cells are usually larger and more complex than prokaryotes

Many protists are?

• unicellular

• Some colonial

• Some multicellular

Two theories of how eukaryotic cells came about ? (1)

Autogenous theory: eukaryotic cells evolved when the plasma membrane of a prokaryote folded inward, forming internal membranes

Two theories of how eukaryotic cells came about ? (2)

Endosymbiotic theory: some organelles originated from bacteria that were engulfed by another cell

Classification of Protista

Protists are classified into 4 major subgroups rather than one kingdom

Four subgroups

• excavata

• SAR

• Archaeplastida

• Unikonta

Supergroup: Excavata Characteristics

• cytoskeleton

• Excavated groove (some)

• Modified mitochondria

Supergroup: Excavata

Clade2: Diplomonads & Parabasala characteristics

• lacks plastids

Supergroup: Excavata characteristics

Clade2: Euglenozoans

• Disc- shaped Cristae

Supergroup: Excavata characteristics

Clade3: kinetoplastids

• single large mitochondria with kinetoplast

Supergroup: Excavata characteristics

Clade3: Euglenids

• broke up the two kingdom systems

Supergroup: SAR characteristics

• DNA sequence data

• Secondary endosymbiosis of a red algae

Supergroup: SAR characteristics

Clade1: Alveolates

• membrane bounded sacs (alveoli)

• DNA similarities

Supergroup: SAR characteristics

Clade2: Dinoflagellates

• causes red tide (brevetoxin)

• Xanthophyll

• 2 flagella, one in a groove, one apical

Supergroup: SAR characteristics

Clade2: apicomplexans

• parasitic

• Apical structure

• Causes Malaria

• Vector anopheles mosquito

Supergroup: SAR characteristics

Clade2: ciliates

• used for movement or feeding

• Two distinct types of nuclei

Supergroup: SAR characteristics

Clade1: Stramenopila

• hair like projections on flagella

• Store food as laminarían

Supergroup: SAR characteristics

Clade2: Bacillariophyta

• overlapping silica test

• Pigments: carotene and xanthophyll

Supergroup: SAR characteristics

Clade2: Chrysophyta

• typically bi flagellated

• Pigments carotene and xanthophyll

Supergroup: SAR characteristics

Clade2: Phaeophyta

• pigment fucoxanthin

• Cell wall: glucose and algin

Supergroup: SAR characteristics

Clade2: Oomycetes

• pigments: none

• Cell wall: cellulose

Supergroup: SAR characteristics

Clade1:

• thin pseudopodia used for movement and feeding

Supergroup: SAR characteristics

Clade2: Cercozoans

• Amoeboid-shaped protist with thin pseudopodia

• Chromatophore

• Predators found in marine freshwater, and soil

Supergroup: SAR characteristics

Clade2: Forminiferans

• Porous shells - calcium carbonate

• Both marine and freshwater found in sand or attached to algae

Supergroup: SAR characteristics

Clade2: Radiolarians

• Fused plates – silica with axopodia

• Mostly Marine

supergroup: Archaeplastida characteristics

• DNA Sequences

• Endosymbiosis of cyanobacterium

Supergroup: Archaeplastida characteristics

Clade2: Rhodophyta

Multicellular (most)

➢Pigment: phycoerythrin

➢Cell wall: cellulose

➢no flagellated stage in their life cycle

➢used to produce agar

Supergroup: Archaeplastida characteristics

Clade2: Chlorophyta

• Mostly Freshwater

• Some marine

• Some terrestrial

• Unicellular, Colonial, Multicellular

• Pigments:Chlorophyll a, b, and carotenoids

• Cell walls: Cellulose