Lecture 23 - Endosymbiotic Theory and Protist Diversity Flashcards Preview

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Flashcards in Lecture 23 - Endosymbiotic Theory and Protist Diversity Deck (21):
1

Darwin thought that evolution was driven by _______

competition

2

What did natural selection favor?

-organisms that were best able to out-compete others
-left more descedants

3

What is another strategy driven by natural selection?

cooperation

4

What is an example of a mutualistic symbiosis?

Clownfish

5

What is symbiosis?

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

6

Who do microbes often form symbiotic relationships with?

-larger organisms
-other microbes

7

What is mutualism?

both symbiotic organisms benefit

8

commensalism

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

9

parasitism

harms but does not kill its host

10

What are pathogens

parasites that cause disease

11

What was the theory of serial endosymbiosis?

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

12

What are endosymbionts

cells that live within other cells

13

What were the proposed ancestors of mitochondria?

-aerobic heterotrophic prokaryotes
-alpha proteobacteria

14

proposed ancestors of chloroplasts?

-photosynthetic prokaryotes
-cyanobacteria

15

What may have been an ancestral host cell

archaean or protoeukaryote

16

What were 3 things that endosymbiosis probably lead to?

1. mitochondria
2. plastids
3. eukaryotic features

17

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

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

18

What is kleptoplastidy?

stealing and using chloroplasts from prey

19

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

-photosynthetic protists
(red + green algae)

20

Where did mitochondria first arise?

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

21

What happens in secondary endosymbiosis?

-red + green algae ingested by heterotrophic eukaryote