Unity and Diversity of Cellular Life
For cellular organisms, Carl Woese developed the taxonomic level of “Domain” based on ribosomal RNA sequences
- In Belk’s Biology, see the “Tree of Life” fig 2.19 on page 47 which illustrates how all cellular organisms evolved from common ancestral prokaryotic organisms.
- This common ancestry explains the unity of life (why all cellular organisms share many processes and structures).
- Evolution explains the great diversity of life (see chapter __ “Microbial Genetics” of the Reader for more info on genetic diversity)
Cellular organisms: prokaryotes and eukaryotes
1. Prokaryote: unicellular organisms which lack membrane bound nucleus and other membrane-bound organelles (no nucleus; unicellular= 1 cell). See fig 2.17 p 41 in Belk’s Biology
2 Domains of prokaryotic organisms
-Domain Archaea : few pathogens (maybe??)
-Domain Bacteria: contains the bacterial pathogens
e.g. Yersinia pestis/Bubonic Plague, Staphylococcus aureus/MRSA, Mycobacterium tuberculosis/TB, E. coli O157:H7, Bacillus anthracis/anthrax
-can treat bacterial pathogens with antibioticx