Lecture 13: Eukaryote Origin & Protists Flashcards
what does eukaryote mean?
-“true nuclues”
eukaryote traits
- multicellularity
- sexual reproduction
- compartmentalization
eukaryotic multicellularity benefits
-allows organisms to be more flexible about the environments that they encounter
eukaryotic sexual reproduction benefits
- leads to introduction of new gene combinations through recombination
- ->promotes diversity & inc. speed of adaptation
primary endosymbiosis
-btwn a cyanobacteria and the ancestor for both red and green algae
why is the loss of the cell wall critical to eukaryotic development?
- allows membrane to fold in on itself
- allows for plasma membrane to fold in on itself
- gives more surface area without increasing size
how does compartmentalization lead to internal structure?
-it can be membrane infolding or engulfing other cells which can lead to endosymbiosis
endosymbiosis leading to mitochondria
- ancestor eukaryotic cell engulfs an aerobic energy producing bacteria (maybe proteobacteria)
- didn’t digest it and became a part of it
endosymbiosis leading to chloroplasts
-engulfment of cyanobacteria
how are protists paraphyletic?
- some are more closely related to plants, fungi, or animals
- MRCA of protists is MRCA of all Euk.
how do protists vary?
- locomotion
- cell surfaces
- nutrition
- reproduction
protist variation: locomotion
- using both flagella and cilia
- some use pseudopods
secondary endosymbiosis
- ancestors to the algae engulfed an already Euk. and photosynthetic red algae or green alga
- -> led to their photosynthetic ability
cilia
-groups of shortened flagella-like protrusions that wave along creating water currents around the whole organism
pseudopods
- aka “false feet”
- use variously sticky shaped protrusions that reach out and adhere to adjacent surfaces
- they roll themselves across the surfaces they’re on
