Honors Biology
Ch. 16 Notes
The Origin Evolution of Microbial Life: Prokaryotes and
Protists
Opening Essay
Describe the formation of stromatolites and explain the
significance of the organisms that produce them.
Formation
1. Shark’s Bay in western Australia
2. photosynthetic prokayotes
3. live on the surface of the stromatolite, exposed to sunlight
4. The sticky coating of these organisms concentrates sand
grains and other fine particles from the seawater.
5. While a sediment layer accumulates, the prokaryotes keep
migrating to the surface and growing over it.
6. A layered mat builds up as this process is repeated.
7. Large mounds form over thousands of years
8. hardening as their older sediment layers solidify and
9. become rocklike structures composed of many layers of
prokaryotes and sediment
10. Cyanobacteria are direct descendants
Significance
Created aerobic atmosphere
Prokaryotes
16.2 Compare the characteristics of the three domains of
life.
Three Domains:
Bacteria: Prokaryotic,
Archaea: Prokaryotic,
Eukarya: Eukaryotic,
Char
rRNA
RNA
Poly
Introns
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Arch
Eu
+ +
+ +
-  +
Antibiotics
- + +
PeptidoGlycan?
+ - -  +
Histones
Mrs. Loyd 
cloyd@waukee.k12.ia.us
Bact
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Protists
16.12 Explain how primary endosymbiosis and secondary
endosymbiosis led to further cellular diversity.
(Origin of Protistan Diversity)
16.21 Explain how multicellular life may have evolved in
eukaryotes.
1. Colonial protist formed when offspring stuck together
2. Cells specialize somewhat and become interdependent
a. efficiency of specialization increases
3. High efficiency: Gamete cells
4. Example: Volvox
a. colonial
b. produces gametes
c. gametes depend on somatic cells while
developing


Modern specialization:

feeding

waste disposal

gas exchange

protection
3 Major lineages formed ancestral eukaryotes

stramenopile  brown algae

unnamed to  red algae, green algae, and land
plants

choanoflagellates  animals
Mrs. Loyd 
cloyd@waukee.k12.ia.us
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