Class Notes (1,100,000)
US (460,000)
UC-Irvine (10,000)
BIO SCI (2,000)
Lecture 13

BIO SCI 94 Lecture 13: Protist Part 2Premium

Biological Sciences
Course Code
Brad Hughes

This preview shows half of the first page. to view the full 3 pages of the document.
How Do Protists Obtain Food?
Bacteria and Archaea have many ways to get food
Evolution of novel methods for finding food important in diversification of protists
Protists ingest food-eat bacteria, archaea, and other protists whole
Feeding methods:
Ingest packets of food
Absorb organic molecules from environment
Perform photosynthesis
Some uses combination of feeding methods
Some lineages can use all three methods
Ingesting Feeding
Ingestive lifestyle-eating live or dead organisms, scavenging organic debris
Some protist big enough to ingest bacteria and archaea whole
Phagocytosis-prerequisite for endosymbiosis→ chloroplasts
Many hunt prey
Some attach themselves to surface
Absorptive Feeding
Absorptive feeding- nutrients cross plasma membrane from environment
Common among protists
Decomposers-feed on detritus, dead organic matter
Live inside other organisms
Parasite-absorptive species damage host
Photosynthesis-Endosymbiosis and the Origin of Chloroplasts
Eukaryotes didn’t have necessary parts for photosynthesis
“Stole” parts using endosymbiosis
Endosymbiosis theory
Protist engulfed cyanobacterium→ birth of eukaryotic chloroplasts
Evidence for endosymbiotic origin for chloroplast:
Chloroplasts similar to bacteria
Animals cells/protists have endosymbiotic cyanobacteria
Chloroplasts have circular DNA molecule with genes similar to
cyanobacterial genes
A protist group has chloroplast with layer of peptidoglycan
Molecule found in cyanobacteria cell walls
Photosynthesis-Primary vs Secondary Endosymbiosis
Hypothesis:Endosymbiosis leading to photosynthesis occurs first in common
ancestor of plantae
Ancestor birthed all plantae subgroups
Chloroplasts in four major protists lineages
You're Reading a Preview

Unlock to view full version

Subscribers Only