Lecture 23 - Endosymbiosis + Eukaryotic Diversity (SI) Flashcards
Serial Endosymbiosis
-hypothesis for origin of eukaryotes
3 proposals of serial endosymbiosis
- ancestors of mitochondria = aerobic, heterotrophic prokaryotic endosymbionts (alpha)
- ancestors of chloroplasts = photosynthetic prokaryotes (cyanobacteria)
- ancestral host = archaean/proto-eukaryote (diverged from archaeal ancestors)
What are 5 pieces of evidence?
chloroplasts/mitochondria + bacteria have similar:
- size
- transcription tools
- enzymes + transport systems
- replication
- ribosomes
Kleptoplastidity
stealing + using chloroplasts from prey
-passed from generation to generation
What are 2 qualities of plastid evolution?
- mitochondria arose through descent from bacterium engulfed by cell from archaeal lineage
- photosynthetic cyanobacterium was engulfed by hetertrophic eukaryote
What did plastid bearing lineage evolve into?
- photosynthetic protists
- red and green algae
What is the evolutionary sequence of land plants?
- cyanobacteria
- green algae
- land plants
how did mitochondria originate?
from engulfed, originally free-living proteobacteria
What catalyzed the 3 adaptive radiations?
- metabolic
- structural
- multicellularity
protists
eukaryotic organisms capable of existence as single cells
Protists often contain _____ at some point in their lifecyle
flagella/cilia
What are Euglena?
- single-celled mixotrophic protist
- live photosynthetically/herterotrophically
Fungus-like
absorptive nutrition
Protozoa
ingestive, animal like nutrition
Algae
photosynthetic plant like
What are the 3 ecological categories of protists?
- protozoa
- fungus-like
- algae
What are eukaryotic flagella?
-extensions of cytoplasm with a support of 9 + 2 microtubule system
What are 4 parasites
- plasmodium (maleria)
- P. ramorum (sudden oak death)
- P. shumayae (kills fish)
- P. infestans (potato late blight)
What are cysts?
- resistant cells formed by protists
- can survive harsh conditions
Plankon
communities of organisms that drift passively or swim weakly in the water
Size of microbial eukaryotes
-single celled (mostly, protists)
Diversity of microbial eukaryotes
tens of thousands of described species
2 types of microbial eukaryotic nutrition
- Photosynthetic (microalgae)
2. Engulfment (protozoa)
3 types of microbial eukaryotic reproduction
- binary fission (most common)
- sexual reproduction/recombination
- budding + multiple fission (least common)
Distribution of microbial eukaryotes
every biotic ecosystem on the planet
many protists are important ______ that obtain energy from the sun
producers
