BIOEE 1780 - Evolutionary Biology & Diversity (Biodiversity 2 - Eukaryotes: Protists)

Protists

a paraphyletic group of eukaryotic organisms that cannot be classified as an animals, plants, or fungi

How were Eukaryotic Cells formed from prokaryotic cells (9 events)

1) Loss of Rigid Cell Wall (Leaving Just Flexible Membrane)

2) Infoldings of Membrane (Increased Surface Area : Volume ratio, allowing for cell to transfer more materials across membrane & thus grow larger)

3) Development of the Cytoskeleton

4) Membrane-Bounds (Organelles) with integral ribosomes (Rough ER)

5) Enclosing of DNA in Nucleus

6) Formation of Flagella (Allowed for Movement)

7) Digestive Vacuoles

8) Endosymbiosis of Proteobacteria (Formation of Mitochondria)

9) Endosymbiosis of Cyanobacteria (Formation of Chloroplasts)

Types of Endosymbiosis (4)

1) Primary - initial engulfing of cyanobacteria which gave rise to chloroplasts; Origin of Glaucophytes, Red/Green Algae, & Land Plants

2) Secondary - engulfing of chloroplast-containing eukaryotic cell with some of its DNA present;

Origin of Euglenids (Engulfed Green Algae) and Stramenopiles & Alveolates (Engulfed Red Algae)

3) Tertiary Endosymbiosis - after loss of initial chloroplast, engulfed protist & acquired its chloroplast;

Origin only of Dinoflagellates (Engulfed Red Algae)

Endosymbiotic Mutualism between Engulfed Bacteria & Host Cell

Cyanobacteria/Proteobacteria had safe environment & nutrients

Host Cell wasn't poisoning by high O2 concentrations in atmosphere due to bacteria undergoing oxidative metabolism

Sister Protist Taxa (4)

1) Alveolates

2) Stramenopiles

3) Excavates

4) Amoebozoans

Alveolates (Type of Endosymbiosis + Physical Traits + Subgroups (4))

One of four sister taxa for protists; All unicellular

Endosymbiosis: Secondary (Red Algae) [Exception: Dinoflagellate]

Physical Traits: Sac Under Membrane called Alveoli

Subgroups: 1) Dinoflagellates, 2) Ciliates, 3) Paramecium, 4) Plasmodium

Stramenopiles (Type of Endosymbiosis + Physical Traits + Subgroups (2))

One of four sister taxa for protists

Endosymbiosis: Secondary (Red Algae)

Physical Traits: 2 Uneven Flagella (One has Tubular Hair)

Subgroups: 1) Brown Algae, 2) Diatoms

Excavates (Type of Endosymbiosis + Physical Traits + Subgroups (3))

One of four sister taxa for protists

Endosymbiosis: None (Don't Have Chloroplasts) [Exception: Euglenids - Secondary to Green Algae]

Physical Traits: Reduced/Lost Mitochondria (Leads to all except Euglenids being parasites)

Subgroups: 1) Giardia, 2) Euglenids, 3) Trypanosoma

Amoebozoans (Type of Endosymbiosis + Physical Traits + Subgroups (2))

Endosymbiosis: None

Physical Traits: Lobe-Shaped pseudopods; Moves via Cytoplasmic Streaming

Subgroups: 1) Amoeba, 2) Slime Molds

Ciliates (Physical Traits, Main Environment, Subgroup)

a group of alveolates;

Physical Traits: covered in hair-like cilia for controlled movement; fairly complex (ex; can be multinuclear);

Environment: Aquatic (ex: freshwater, marine, moist soil)

Subgroup: Paramecium

Dinoflagellates (Physical Traits, Endosymbiosis, Disease/Ecology [3])

a group of alveolates;

Physical Traits: Possesses 2 flagella (one equatorial, another longitudinal);

Endosymbiosis: Tertiary (Engulfed Red Algae)

Disease/Ecology:

1) Red Tide - blooms that release neurotoxins in waters & facilitate an anaerobic environment

2) Bioluminescence

3) Endosymbiotic with Coral

Plasmodium (Physical Traits, Disease/Ecology)

a group of alveolates; intracellular parasites

Physical Traits: Degenerate/Vestigial Chloroplast (leads to it being parasitic); Complex of Proteins at Apical Prominence (used to penetrate host cell)

Disease/Ecology: Malaria

Brown Algae (Physical Traits + Disease/Ecology)

a group of Stramenopiles (kelp - not "true" algae)

Physical Traits: Large & Multicellular

Disease/Ecology:

Forms Kelp Forests

Diatoms (Physical Traits & Disease Ecology [3])

a group of Stramenopiles (unicellular)

Physical Traits: Secondarily Lost Double Flagella

Disease/Ecology:

1) Responsible for significant portion of Carbon Fixation on Earth

2) Mostly Marine

3) Deposits Silica Shells of various geometric patterns/designs

Giardia (Physical Traits & Disease Ecology)

a group of excavates;

Physical Traits: Degenerate Mitochondria

Disease/Ecology:

Food/Water Poisoning (Most Common Intestinal Parasite)

Trypanosoma (Physical Traits & Disease Ecology [3])

a group of excavates;

Physical Traits: Singe Large Mitochondrion

Disease/Ecology:

1) Sleeping Sickness

2) Chagas' Disease

3) Leishmaniasis