Lecture 23 - Endosymbiosis + Eukaryotic Diversity (SI)

Question 1

Serial Endosymbiosis

Answer 1

-hypothesis for origin of eukaryotes

Question 2

3 proposals of serial endosymbiosis

Answer 2

1. ancestors of mitochondria = aerobic, heterotrophic prokaryotic endosymbionts (alpha)
2. ancestors of chloroplasts = photosynthetic prokaryotes (cyanobacteria)
3. ancestral host = archaean/proto-eukaryote (diverged from archaeal ancestors)

Question 3

What are 5 pieces of evidence?

Answer 3

chloroplasts/mitochondria + bacteria have similar:

1. size
2. transcription tools
3. enzymes + transport systems
4. replication
5. ribosomes

Question 4

Kleptoplastidity

Answer 4

stealing + using chloroplasts from prey

-passed from generation to generation

Question 5

What are 2 qualities of plastid evolution?

Answer 5

1. mitochondria arose through descent from bacterium engulfed by cell from archaeal lineage
2. photosynthetic cyanobacterium was engulfed by hetertrophic eukaryote

Question 6

What did plastid bearing lineage evolve into?

Answer 6

• photosynthetic protists

- red and green algae

Question 7

What is the evolutionary sequence of land plants?

Answer 7

1. cyanobacteria
2. green algae
3. land plants

Question 8

how did mitochondria originate?

Answer 8

from engulfed, originally free-living proteobacteria

Question 9

What catalyzed the 3 adaptive radiations?

Answer 9

1. metabolic
2. structural
3. multicellularity

Question 10

protists

Answer 10

eukaryotic organisms capable of existence as single cells

Question 11

Protists often contain _____ at some point in their lifecyle

Answer 11

flagella/cilia

Question 12

What are Euglena?

Answer 12

• single-celled mixotrophic protist

- live photosynthetically/herterotrophically

Question 13

Fungus-like

Answer 13

absorptive nutrition

Question 14

Protozoa

Answer 14

ingestive, animal like nutrition

Question 15

Algae

Answer 15

photosynthetic plant like

Question 16

What are the 3 ecological categories of protists?

Answer 16

1. protozoa
2. fungus-like
3. algae

Question 17

What are eukaryotic flagella?

Answer 17

-extensions of cytoplasm with a support of 9 + 2 microtubule system

Question 18

What are 4 parasites

Answer 18

1. plasmodium (maleria)
2. P. ramorum (sudden oak death)
3. P. shumayae (kills fish)
4. P. infestans (potato late blight)

Question 19

What are cysts?

Answer 19

• resistant cells formed by protists

- can survive harsh conditions

Question 20

Plankon

Answer 20

communities of organisms that drift passively or swim weakly in the water

Question 21

Size of microbial eukaryotes

Answer 21

-single celled (mostly, protists)

Question 22

Diversity of microbial eukaryotes

Answer 22

tens of thousands of described species

Question 23

2 types of microbial eukaryotic nutrition

Answer 23

1. Photosynthetic (microalgae)

2. Engulfment (protozoa)

Question 24

3 types of microbial eukaryotic reproduction

Answer 24

1. binary fission (most common)
2. sexual reproduction/recombination
3. budding + multiple fission (least common)

Question 25

Distribution of microbial eukaryotes

Answer 25

every biotic ecosystem on the planet

Question 26

many protists are important ______ that obtain energy from the sun

Answer 26

producers