12-Diversity%20of%20lifenotes-1

12-Diversity%20of%20lifenotes-1 - TheDiversityofLife...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
The Diversity of Life Classification schemes - Diversity of life is overwhelming - Need some system to give order to this - Classification scheme     : - The method by which organisms are grouped, categorized, and named - How to categorize organisms to get the most information out of the name and  organization? Binary naming system - Binary naming system     : organisms have two-part names - Examples:  Homo sapiens  (humans) ; Canis familiaris  (dogs) - Classification is hierarchical - Higher order taxa contain lower levels - Higher levels inclusive of multiple lower levels - Previously based on simple similarity - Now tied to evolutionary history: descent from a common ancestor (homology) Linnaean system: Kingdom Phylum Class Order Family Genus Species King Phillip Could Order Five Good Sheep Kids Prefer Cheese Over Fried Green Spinach Example: Kingdom Animalia Phylum Chordata Class Mammalia Order Primata Family Hominidae Genus Homo Species H. sapiens
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Six Kingdoms/Three Domains - Six Kingdoms     - Comparison revealed two to be very distinctive from the other four - Group the four together - The other two (bacteria and archaea) individually - Three domains     - Taxonomic level “Domain” placed above “kingdom” - Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species - Eukarya:  - All eukaryotes - includes animals, plants, fungi and protists - all have membrane bound nucleus - Not all are single-celled organisms - Complex intracellular organization - Have many organelles/endomembrane system - Eukaryotic replication/gene expression machinery - Have standard membrane lipids (ester link) - Archaea - Formerly Archaebacteria - All are single-celled - Membrane lipids with ether linkages - Pseudopeptidoglycan cell wall - Replication/gene expression machinery similar to eukaryotes - Often found in extreme environments - Bacteria - “standard” bacteria - All are single-celled organisms - Have standard membrane lipids (ester link) - Peptidoglycan cell wall - Replication/gene expression machinery is distinctly bacterial - Many are photosynthetic/important nutrient cyclers - At the base of trophic levels Relationships among Domains - 3 domains represent the oldest divergence in the history of life - Which diverged first? - Bacteria may have diverged first - Difficult to tell—conflicting phylogenies - Occurred in the distant past
Background image of page 2
- Early lateral gene transfer - Swapping of genetic information between  species - Figure 26.7 Diversity of animal Phyla - Assignment to phyla traditionally based on body plans and development - Body plans: - Tissue layers (arise during development) - Symmetry (radial or bilateral)  - Internal cavity (coelom)
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 03/25/2010 for the course BIO 11000 taught by Professor Friedman during the Spring '10 term at Purdue University-West Lafayette.

Page1 / 9

12-Diversity%20of%20lifenotes-1 - TheDiversityofLife...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online