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

Classific ation

Supergroup: Excavata
 Cytoskeleton features
 Excavated groove (some)
 Modified mitochondria

Supergroup:
Excavata
Clade
2
:
Diplomonads ex.
(lack plastids, lack functional etc in mitochondria
(mitostomes), two haploid nuclei, flagella)

Supergroup:
Excavata
Clade
2
:
Parabasala ex
(lack plastids, reduced mitochondria
(hydrogenosomes , undulating membranes and flagella)

Supergroup: Excavata
Clade
2
: Euglenozoans
 Move by flagella with spiral or crysalline rod
 Disc-shaped Cristae

2
Clade
3
:
Kinetoplastids ex.
(single large mitochondria with kinetoplast)

Supergroup:
Excavata
Clade
2
:
Euglenozoans
Clade
3
:
Euglenids ex.
(anterior pocket with flagella)

Supergroup: Chromalveolates
 DNA Sequence Data
 Secondary endosymbiosis of a red alga

Supergroup: Chromalveolates
Clade
1
: Alveolates
 DNA Similarities
 Membrane bounded sacs (alveoli)

1
Clade
2
:
Dinoflagellates
Causes Red Tide
(2 flagella in grooves, xanthophyll)

Supergroup: Chromalveolates
Clade
1
: Alveolata
Clade
2
:
Apicomplexans ex.
(parasitic, apical structure)

Supergroup: Chromalveolates
Clade
1
: Alveolata
Clade
2
: Ciliates (cilia),
Ex. Vorticella, paramecium
Cilia, two distinct types of nuclei

Supergroup: Chromalveolates
Clade
1
: Stramenopila
 Have hair-like projections on flagella
 Store food as laminarin (Photosynthetic)

Supergroup:
Chromalveolates
Clade
1
:
Stramenopila
Clade
2
:Diatoms overlapping silica test pigments: carotene, xanthophyll

Supergroup:
Chromalveolates
Clade
1
:
Stramenopila
Clade
2
: Chrysophyta ex. Golden Algae
Typically bi-flagellated pigments: carotene, xanthophyll

Supergroup:
Chromalveolates
Clade
2
: Brown Algae
Clade
1
:
Stramenopila pigments: fucoxanthin cell wall: cellulose, algin

Supergroup: Chromalveolates
Clade
2
Clade
1
: Stramenopila
: Oomycota ex. Water mold pigments:none cell wall: cellulose, coenocytic hyphae

Supergroup: Rhizaria
 Thin pseudopodia used for movement and feeding

Supergroup: Rhizaria
Clade
2
:Cercozoans
Amoeboid-shaped protist with thin pseudopodia
Predators found in marine freshwater, and soil

Supergroup: Rhizaria
Clade
2
: Forams
(porous shells - calcium carbonate)
Both marine and freshwater (found in sand or attached – also planktonic)

Supergroup: Rhizaria
Clade
2
:Radiolarians (fused plates – silica with axopodia)
Mostly Marine (usually planktonic)

Supergroup: Archaeplastida
 DNA Sequences
 Endosymbiosis of cyanobacterium

Supergroup:
Archaeplastida
Clade
2
:
Red Algae

Supergroup: Archaeplastida
Clade
2
: 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
Clade
2
: Chlorophytes


Supergroup: Archaeplastida
Clade
2
: Chlorophytes
Mostly Freshwater
– Some marine
– Some terrestrial
 Unicellular, Colonial, Multicellular
 Pigments:Chlorophyll a, b, and carotenoids
 Cell walls: Cellulose


Supergroup: Archaeplastida
Clade
2
: Charophytes
Similar to higher plants in color
(pigment: Chlorophyll
A and B and carotenoids). They are the closest relatives of land plants.


Supergroup: Archaeplastida
Clade
2
: Charophytes
Four distinctive traits that are shared with higher plants:
1.
2.
3.
4.
Rings of cellulose-synthesizing proteins
Peroxisome enzymes
Structure of flagellated sperm
Formation of a phragmoplast

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

Supergroup: Unikonts
Clade
1
: Amoebozoans
 Used for movement and feeding
 Classification
– Slime Molds
 Plasmoidial
 Cellular
– Gymnamoebas (broad pseudopods)
– Entamoebas (parasitic)

Supergroup: Unikonts
Clade
Clade
2
1
: Amoebozoans
: The Slime Molds

3

 (feeding stage) single mass of cytoplasm with many nuclei
– Diploid

Supergroup: Unikonts
Clade
Clade
2
1
: Amoebozoans
: The Slime Molds

3
 (feed like individual amoebas)
 Septate hyphae
– aggregate to breed or during stress

Supergroup: Unikonts
Clade
1
: Amoebozoans
Clade
2
:
Gymnamoebas ex. Amoebas

Supergroup: Unikonts
Clade
1
: Amoebozoans
Clade
2
:
Entamoebas ex.


Supergroup: Unikonts
Clade
1
: Opisthokonts
Unicellular and multicellular with ties to fungi and animals (DNA sequences)
 Posterior location of flagellum
 Classification
– Nucleariids
– Choanoflagellates


Supergroup: Unikonts
Clade
1
: Opisthokonts
Clade
2
: Nucleariids
Unicellular – lack distinctive characters
 Contain a posterior flagella
 Temporary pseudopods
 Feed on algae and bacteria

Supergroup: Unikonts
Clade
Clade
2
1
: Opisthokonts
: Choanoflagellates
 Unicellular or colonial
 Most are suspension feeders