25-origin & Diversification Of Eukarotes

Question 1

Protists

Answer 1

Informal group of small, unicellular, mostly aquatic eukaryotes
-polyphyletic

Question 2

Steps of eukaryotic origin

Answer 2

-flexible cell wall
-more surface area with Sam surface area to volume ratio (bigger cells)
-cell structure & function changes
-nucleus
-complex cytoskeleton
-RER
-flagellum
-digestive vacuoles
-endosymbiosis
-mitochondria & chloroplast
(Autapomorphies)

Question 3

Endosymbiosis

Answer 3

• primary endosymbiosis (2 organisms)
  - initial incorporation of bacteria into eukaryotic machinery
  - mitochondria from proteobacteria
  - chloroplast from Cyanobacteria
• secondary endosymbiosis
  - another cell ingests one of those ^
• tertiary endosymbiosis

Question 4

4 supergroups of protists

Answer 4

• SAR
• Excavates
• Archaeplastida
• Unikonta

Question 5

Supergroup “SAR”

Answer 5

-large and extremely diverse

• Stramenopiles
• Alveolates
• Rhizarians

Question 6

Stramenopiles (subgroup)

Answer 6

• mostly photosynthetic
• all have flagella

Diatoms
Brown algae
Oomycetes

Question 7

Diatoms (clade)

Answer 7

• unicellular
• silicon-dioxide shell (intricate Petri dish)
• large component of global O2 production
• diatomaceous earth (huge accumulations)

Question 8

Brown algae (clade)

Answer 8

• largest and most diverse algae
• multicellular
• analogous structures to plants (thallus, stipe, holdfast, blades)

Question 9

Oomycetes (clade)

Answer 9

• filamentous
• stationary
• absorvative heterotrophs
• saprobes (feed on dead organic material)
• cellulose in cell wall
• similarities to fungi

Question 10

Alveolata (subgroup)

Answer 10

• membrane bound sacs (alveoli)
• unicellular
• most are photosynthetic

Dinoflagellates
Apicomplexins
Ciliates

Question 11

Dinoflagellates (clade)

Answer 11

• cellulose plates
• flagella in groove between plates (spin as move)
• huge component of phytoplankton
• Red tides

Question 12

Apicomplexins (clade)

Answer 12

-all are animal parasites
-contain apex for penetrating hosts
-complex life cycle with both sexual and asexual phases (multiple hosts)
(Malaria)

Question 13

Ciliates (clade)

Answer 13

• named for cilia
• 2 types of nuclei (micro and macro)
• undergo conjugation
• most are heterotrophs (a few symbionts)

Question 14

Rhizarians (subgroup)

Answer 14

• unicellular
• mostly aquatic
• pseudopodia

Radiolarians
Forams
Cercozoans

Question 15

radiolarians (clade)

Answer 15

• delicate
• symmetrical internal skeletons made of silica
• radial symmetry
• pseudopodia radiate from central body, and are reinforced by microtubules

Question 16

Foraminiforans (clade)

Answer 16

• porous shell called tests
• contain calcium carbonate
• limestone deposits
• heterotrophs

Question 18

Supergroup Excavata

Answer 18

• unique cytoskeleton
• either no mitochondria, or highly modified
• excavated feeding groove

Diplomonads
Parabasilids
Euglenozoans

Question 19

Diplomonads (subgroup)

Answer 19

• mostly anaerobic
• mitosome
• 2 equal size nuclei
• multiple flagella
• many parasites

Question 20

Parabasilid (subgroup)

Answer 20

• mostly anaerobic
• hydrogen sores
• many parasites

Question 21

Euglenozoans (subgroup)

Answer 21

• very diverse
• mitochondria have disc-shaped Cristae
• spiral rod in flagella

Kinetoplastids
Euglenids

Question 22

Kinetoplastids (clade)

Answer 22

• 1 large mitochondria

- trypansoma

Question 23

Euglenids (clade)

Answer 23

• pocket at one end with 1 or 2 flagella

- many are mixotrophs

Question 24

Supergroup archaeplastida

Answer 24

• red algae
• green algae
• common ancestor absorbed photosynthetic Cyanobacteria

Question 25

Red algae (subgroup)

Answer 25

• red photosynthetic pigment
• most are multicellular (some seaweeds)
• diverse life cycle with no flagellated stage

Question 26

Green algae (subgroup)

Answer 26

• closest relatives of land plants
• charaphytes (closely related to plants)
• chlorphytes (extremely variable)

Question 27

Supergroup Unikonta

Answer 27

-very diverse

Ameobozoans
Opisthokonts

Question 28

Ameobozoans (subgroup)

Answer 28

-tube shaped pseudopodia

Loboseans
Plasmodia slide molds
Cellular slime molds

Question 29

Losobeans (clade)

Answer 29

• unicellular
• tube shaped pseudopodia
• shells of sand
• prey on bacteria or eat detritus

Question 30

Plasmodia slime molds (clade)

Answer 30

• brightly colored
• form mass called plasmodium (mitosis NOT followed by cytokinesis)
• engulf nutrients via phagocytosis
• moves via pseudopodia
• when environmental conditions are bad, plasmodium stops growing and creates fruiting bodies (sexual reproduction)

Question 31

Cellular slime molds (clade)

Answer 31

• feeding stage consists of solitary cells (amoebas) that act as individual organisms
• when food is scarce, they aggregate and function as a multicellular organism
• cells are still separated
• produce fruiting bodies that make spores (asexual reproduction)
• can also reproduce sexually when 2 amoebas fuse and divide

Question 32

Opisthokonts (subgroup)

Answer 32

• group called nuclearids are closely related to fungi

- group called choanoflagellates are closely related to animals

Question 33

Asexual processes

Answer 33

• mitosis then cytokinesis (2 cells)
• splitting of 1 cell into more than 2
• budding (outgrowth of new cell from surface of another)
• sporulation (formation of spores)

Question 34

Sexual processes

Answer 34

• conjugate then divide asexually

- separates sex and reproduction

Question 35

Cercozoans (clade)

Answer 35

• ameboid
• flagella
• threadlike pseudopodia for feeding
• most are parasites or predators (heterotrophs)
• some have plastic originating from secondary endosymbiosis