Chapter 25: The Origin/Diversification of Eukaryotes

Question 1

What are Eukaryotic cells?

Answer 1

cells that contain membrane-enclosed nucleus/organelles

Question 2

What are the four subgroups of Eukaryotes?

Answer 2

Excovata, SAR, Archaeplastida, Unikonta

Question 3

What characteristics do Eukaryotic cells have?

Answer 3

-A membrane-enclosed nucleus
-Membrane-bound organelles
-Cytoskeleton
-Linear DNA

Question 4

What is a Pairwise Comparison Matrix?

Answer 4

compares genetic sequences for rRNA% similarity in sequences

Question 5

What kind of organisms are Eukaryotes?

Answer 5

“Combination” with some genes/characteristics derived from Archaea and Bacteria

Question 6

Which bacteria is most similar in rRNA to mitochondria?

Answer 6

A. tumefaciens

Question 7

What is endosymbiosis?

Answer 7

a symbiotic relationship in which one organism lives inside the body/cell of another.

Question 8

How did the rise of Eukaryotes begin?

Answer 8

An Archaeal cell engulfed a Bacterial cell that would later become an organelle found in all eukaryotes (the mitochondrion)

Question 9

What is the Endosymbiont Theory?

Answer 9

Mitochondria and plastids were formerly small bacteria that began living within larger cells

Question 10

How did Bacterial symbionts originate in Archaeal host cells?

Answer 10

Through undigested prey and internal parasites

Question 11

What is the evidence of endosymbiotic origin of mitochondria/plastids?

Answer 11

1. Inner membranes have transport systems like those of plasma membranes in living bacteria.
2. Mitochondria/plastids undergo binary fission.
3. DNA is circular.
4. Have their own cellular machinery to transcribe/translate DNA to protein.
5. Ribosomes are more like those of bacteria than those of ribosomes in the cytoplasm of Eukaryote cells.

Question 12

What conditions would result in selection for an aerobic endosymbioant?

Answer 12

An anaerobe living in an env’t with increasing 02

Question 13

What Eukaryotes have plastids?

Answer 13

Algae, photosynthetic protists, and all photosynthetic eukaryotes EXCEPT plants

Question 14

Did Plastid Evolution by secondary endosymbiosis create a lot of diversity?

Answer 14

Yes

Question 15

What are the oceanic primary producers?

Answer 15

Algae + cyanobacteria

Question 16

Is NPP high or low in oceans?

Answer 16

Low

Question 17

What did the 1st wave of eukaryotic diversification bring?

Answer 17

Greater complexity of unicellular forms

Question 18

What did the 2nd wave of eukaryotic diversification bring?

Answer 18

The evolution of multicellularity

Question 19

What are the two steps to multicellularity?

Answer 19

The formation of colonies and differential cells

Question 20

Why are special mechanisms required for animals?

Answer 20

enables the cells to adhere and communicate with each other

Question 21

What are choanoflagellates?

Answer 21

-the closest living protist to humans
-all unicellular or colonies
-have homologous mechanisms for adherence and signaling

Question 22

What defines the supergroup of Excavata?

Answer 22

Species that have excavated feeding groove

Question 23

What are the subgroups of Excavata?

Answer 23

Diplomonads/Parabasalids + Evglenozoans

Question 24

What defines a Diplomonad/Parabasalid?

Answer 24

-having a reduced mitochondria
-are anaerobic
-Many being parasitic

Question 25

What defines a Evglenozoan?

Answer 25

-A diverse clade
-are heterotrophs, photosynthetic autotrophs, parasites
-Have a presence of a rod with crystalline structure inside of the flagella

Question 26

What defines the supergroup of SAR Stramenopiles?

Answer 26

-secondary endosymbiosis
-important photosynthetic organisms

Question 27

What are the subgroups of SAR Stramenopiles?

Answer 27

Diatoms + Brown Algae

Question 28

What defines the supergroup of SAR Alveolates?

Answer 28

-membrane-enclosed sacs (alveoli)
-secondary endosymbiosis
-photosynthetic/heterotrophic

Question 29

What defines a Diatom?

Answer 29

-unicellular algae
-highly diverse
-unique wall structure of silicone dioxide

Question 30

What defines Brown Algae?

Answer 30

-largest and most complex algae
-multicellular
-marine
-lack true tissues/organs

Question 31

What defines a Dinoflagellate?

Answer 31

-spin as they move
-mixotrophs
-some produce toxins

Question 32

What are the subgroups of SAR Alveolates?

Answer 32

Dinoflagellate + Ciliates

Question 33

What defines a Ciliate?

Answer 33

-cilia to move/feed
-predatory

Question 34

What defines the supergroup SAR Rhizarians?

Answer 34

-amoebas and flagellated non-amoeboids
-pseudopodia

Question 35

What are the subgroups of SAR Rhizarians?

Answer 35

Forams + Cercozoans

Question 36

What defines a Foram?

Answer 36

-tests with little holes
-symbiotic algae in tests
-single-celled

Question 37

What defines a Cercozoan?

Answer 37

marine, freshwater, soil
-parasitic, predators, mixotrophs

Question 38

What defines the supergroup of Archaeplastids?

Answer 38

-Red algae
-green algae
-plants

Question 39

What defines red algae?

Answer 39

-Reddish pigment masks chlorophyll
-survive in deeper depths
-multicellular
-photosynthetic and heterotrophs

Question 40

What defines green algae?-

Answer 40

-similar chloroplasts to plants
-Charophytes
-Chlorophytes

Question 41

What defines the supergroup of Unikonta Amoebozoans?

Answer 41

-unicellular
-multicellular (slime molds)

Question 42

What makes up Unikonta Amoebozoans?

Answer 42

Tubulinids + slime molds

Question 43

What defines a Tubulinid?

Answer 43

-unicellular
-Heterotrophs (some feed on detritus)
-soil, freshwater, marine

Question 44

What defines a slime mold?

Answer 44

-produce fruiting bodies
-Feeding stage–> solitary cells
-reproductive stage–> aggregate

Question 45

What are the 4 Eukaryotic supergroups?

Answer 45

Excavata, SAR, Archaeplastids, and Unikonta