Lecture 23 - Endosymbiotic Theory and Protist Diversity

Question 1

Darwin thought that evolution was driven by _______

Answer 1

competition

Question 2

What did natural selection favor?

Answer 2

• organisms that were best able to out-compete others

- left more descedants

Question 3

What is another strategy driven by natural selection?

Answer 3

cooperation

Question 4

What is an example of a mutualistic symbiosis?

Answer 4

Clownfish

Question 5

What is symbiosis?

Answer 5

• ecological relationship

- 2 species live in close contact: larger host, smaller symbiont

Question 6

Who do microbes often form symbiotic relationships with?

Answer 6

• larger organisms

- other microbes

Question 7

What is mutualism?

Answer 7

both symbiotic organisms benefit

Question 8

commensalism

Answer 8

one organism benefits white neither helping/harming the other in any sig. way

Question 9

parasitism

Answer 9

harms but does not kill its host

Question 10

What are pathogens

Answer 10

parasites that cause disease

Question 11

What was the theory of serial endosymbiosis?

Answer 11

• mitochondria and chloroplasts were formally small prokaryotes living within larger cells
• endosymbionts

Question 12

What are endosymbionts

Answer 12

cells that live within other cells

Question 13

What were the proposed ancestors of mitochondria?

Answer 13

• aerobic heterotrophic prokaryotes

- alpha proteobacteria

Question 14

proposed ancestors of chloroplasts?

Answer 14

• photosynthetic prokaryotes

- cyanobacteria

Question 15

What may have been an ancestral host cell

Answer 15

archaean or protoeukaryote

Question 16

What were 3 things that endosymbiosis probably lead to?

Answer 16

1. mitochondria
2. plastids
3. eukaryotic features

Question 17

What are 5 similarities between bacteria and chloroplasts/mitochondria of eukaryotes?

Answer 17

1. similar size
2. enzymes + transport systems
3. replication
4. transfer RNAs, ribosomes
5. ribosomes

Question 18

What is kleptoplastidy?

Answer 18

stealing and using chloroplasts from prey

Question 19

What did the plastid-bearing lineage of protists evolve into?

Answer 19

-photosynthetic protists

red + green algae

Question 20

Where did mitochondria first arise?

Answer 20

-through descent from a bacterium that was engulfed by a cell from an archaeal lineage

Question 21

What happens in secondary endosymbiosis?

Answer 21

-red + green algae ingested by heterotrophic eukaryote