Lecture 23 - Endosymbiotic Theory and Protist Diversity Flashcards
(21 cards)
Darwin thought that evolution was driven by _______
competition
What did natural selection favor?
- organisms that were best able to out-compete others
- left more descedants
What is another strategy driven by natural selection?
cooperation
What is an example of a mutualistic symbiosis?
Clownfish
What is symbiosis?
- ecological relationship
- 2 species live in close contact: larger host, smaller symbiont
Who do microbes often form symbiotic relationships with?
- larger organisms
- other microbes
What is mutualism?
both symbiotic organisms benefit
commensalism
one organism benefits white neither helping/harming the other in any sig. way
parasitism
harms but does not kill its host
What are pathogens
parasites that cause disease
What was the theory of serial endosymbiosis?
- mitochondria and chloroplasts were formally small prokaryotes living within larger cells
- endosymbionts
What are endosymbionts
cells that live within other cells
What were the proposed ancestors of mitochondria?
- aerobic heterotrophic prokaryotes
- alpha proteobacteria
proposed ancestors of chloroplasts?
- photosynthetic prokaryotes
- cyanobacteria
What may have been an ancestral host cell
archaean or protoeukaryote
What were 3 things that endosymbiosis probably lead to?
- mitochondria
- plastids
- eukaryotic features
What are 5 similarities between bacteria and chloroplasts/mitochondria of eukaryotes?
- similar size
- enzymes + transport systems
- replication
- transfer RNAs, ribosomes
- ribosomes
What is kleptoplastidy?
stealing and using chloroplasts from prey
What did the plastid-bearing lineage of protists evolve into?
-photosynthetic protists
red + green algae
Where did mitochondria first arise?
-through descent from a bacterium that was engulfed by a cell from an archaeal lineage
What happens in secondary endosymbiosis?
-red + green algae ingested by heterotrophic eukaryote
