Origins of Eukaryotic Diversity

Eukaryotic Tree

Characteristics

Nucleus Membrane-bound

organelles Ribosomes (80s) Usually unicellular

– some colonial– some multicellular

Protozoa– ingestive

Algae– autotrophic

Fungus-like– absorptive

Origin of Eukaryotes

Autogeneous Endosymbiotic

Secondary Endosymbiosis

Phylogeny of Eukarya

Classification

Supergroup: Excavata

Cytoskeleton features Excavated groove (some) Modified mitochondria

Supergroup: ExcavataClade2:

Diplomonads

ex. Giardia

(lack plastids, lack functional etc in mitochondria (mitostomes),two haploid nuclei, flagella)

Supergroup:

ExcavataClade2:

Parabasala

ex. Trichimonas

(lack plastids, reduced mitochondria (hydrogenosomes, undulating membranes and flagella)

Supergroup: ExcavataClade2: Euglenozoans

Move by flagella with spiral or crysalline rod

Disc-shaped Cristae

Supergroup: ExcavataClade2:

Euglenozoans

Clade3: Kinetoplastids

ex. Trypanosoma

(single large mitochondria with kinetoplast)

Supergroup: ExcavataClade2:

Euglenozoans

Clade3:Euglenids

ex. Euglena

(anterior pocket with flagella)

Supergroup: Chromalveolates

DNA Sequence Data Secondary endosymbiosis of a red alga

Supergroup: ChromalveolatesClade1: Alveolates

DNA Similarities Membrane bounded sacs (alveoli)

Supergroup: ChromalveolatesClade1:Alveolata

Clade2: Dinoflagellates

Causes Red Tide

(2 flagella in grooves, xanthophyll)

Supergroup: ChromalveolatesClade1: Alveolata

Clade2: Apicomplexansex. Plasmodium(parasitic, apical structure)

Supergroup: ChromalveolatesClade1: Alveolata

Clade2: Ciliates (cilia),

Ex. Vorticella, paramecium

Cilia, two distinct types of nuclei

Supergroup: Chromalveolates

Clade1: Stramenopila Have hair-like projections on flagella Store food as laminarin (Photosynthetic)

Supergroup: Chromalveolate

sClade1:

Stramenopila

Clade2:Diatoms

overlapping silica test

pigments: carotene, xanthophyll

Supergroup: Chromalveolat

esClade1:

Stramenopila

Clade2: Chrysophyta

ex. Golden Algae

Typically bi-flagellated

pigments: carotene, xanthophyll

Supergroup: Chromalveolates

Clade1:Stramenopila

Clade2: Brown Algae

pigments: fucoxanthin

cell wall: cellulose, algin

Supergroup: Chromalveolates

Clade1: Stramenopila Clade2: Oomycota ex. Water mold

pigments:none

cell wall:

cellulose,

coenocytic hyphae

Supergroup: Rhizaria

Thin pseudopodia used for movement and feeding

Supergroup: RhizariaClade2:Cercozoans

Amoeboid-shaped protist with thin pseudopodia

Predators found in marine freshwater, and soil

Supergroup: RhizariaClade2: Forams

(porous shells - calcium carbonate)

Both marine and freshwater (found in sand or attached – also planktonic)

Supergroup: Rhizaria

Clade2:Radiolarians (fused plates – silica

with axopodia)Mostly Marine (usually planktonic)

Supergroup: Archaeplastida

DNA Sequences Endosymbiosis of cyanobacterium

Supergroup: Archaeplastida

Clade2: Red Algae

Supergroup: Archaeplastida

Clade2: Red Algae Multicellular (most) Pigment: phycoerythrin Cell wall: cellulose no flagellated stage in their life cycle

– probably lost during their history used to produce agar

Supergroup: Archaeplastida

Clade2: Chlorophytes

Supergroup: Archaeplastida

Clade2: Chlorophytes Mostly Freshwater

– Some marine

– Some terrestrial Unicellular, Colonial, Multicellular Pigments:Chlorophyll a, b, and

carotenoids Cell walls: Cellulose

Supergroup: Archaeplastida

Clade2: Charophytes Similar to higher plants in color (pigment: Chlorophyll A and B and carotenoids). They are the closest relatives of land plants.

Supergroup: Archaeplastida

Clade2: Charophytes Four distinctive traits that are shared with higher plants:

1. Rings of cellulose-synthesizing proteins

2. Peroxisome enzymes

3. Structure of flagellated sperm

4. Formation of a phragmoplast

Supergroup: Unikonts

Single flagella (in those that have one) Lobed-or tube-shaped pseudopodia Fusion of three genes

Supergroup: UnikontsClade1: Amoebozoans

Used for movement and feeding Classification

– Slime Molds Plasmoidial Cellular

– Gymnamoebas (broad pseudopods)– Entamoebas (parasitic)

Supergroup: UnikontsClade1: Amoebozoans

Clade2: The Slime Molds Clade3: Plasmoidial Coenocytic Hyphae (feeding stage) single mass

of cytoplasm with many nuclei– Diploid

Supergroup: UnikontsClade1: Amoebozoans

Clade2: The Slime Molds Clade3: Cellular (feed like individual

amoebas) Septate hyphae

– aggregate to breed or during stress

Supergroup: UnikontsClade1: Amoebozoans

Clade2: Gymnamoebasex. Amoebas

Supergroup: UnikontsClade1: Amoebozoans

Clade2: Entamoebasex. Entamoeba histolytica

Supergroup: UnikontsClade1: Opisthokonts

Unicellular and multicellular with ties to fungi and animals (DNA sequences)

Posterior location of flagellum Classification

– Nucleariids

– Choanoflagellates

Supergroup: UnikontsClade1: OpisthokontsClade2: Nucleariids

Unicellular – lack distinctive characters Contain a posterior flagella Temporary pseudopods Feed on algae and bacteria

Supergroup: UnikontsClade1: Opisthokonts

Clade2: Choanoflagellates Unicellular or colonial Most are suspension feeders