1. Building the Tree of Life (Ch 18.3)
Unit 5: Evolution

2. Changing Ideas About Kingdoms
Linnaeus was able to differentiate between animals and plants, but that does not reflect the full diversity of life
Five Kingdoms
Single-celled eukaryotic organisms (Protista)
All prokaryotes that lack nuclei, mitochondria, and chloroplasts
Yeasts and molds were placed in their own kingdom (Fungi)
Kingdoms: Monera, Protista, Fungi, Plants, Animals

3. Changing Ideas About Kingdoms
Six Kingdoms
Bacteria needed to be split into two categories because of their genetic makeup (Monera → Archaebacteria and Eubacteria)
Kingdoms: Archaebacteria, Eubacteria, Protista, Fungi, Animalia, Plantae
Three Domains
Domain: larger more inclusive category than a kingdom
Domains: Bacteria (Eubacteria), Archaea (Archaebacteria), Eukarya (Fungi, Animalia, Plantae, and “Protista”)
Protista is in “ “ because it is not a true clade -- there is no way to classify all unicellular organisms under this kingdom

4. Evolution of Kingdoms

5. A Tree of Life
The tree of life shows current hypotheses regarding evolutionary relationships among the taxa within the three domains of life
Domain: Archaea (Archaebacteria)
Unicellular and prokaryotic
Lives in extreme environments
Most can only survive in the absence of oxygen
Their membranes contain unusual lipids and their cell walls do not contain peptidoglycan
Example: Sulfolobus
Domain: Bacteria (Eubacteria)
Unicellular and prokaryotic
Thick, rigid cell walls made of peptidoglycan
Ecologically diverse: free-living to dead parasites
Some require oxygen and some undergo photosynthesis
nitrogen fixation -- turns nitrogen into usable form
Example: Salmonella typhimurium

6. A Tree of Life Domain Eukarya: Fungi Multicellular -- Heterotrophs
Cell walls contain chitin
Feed on dead or decaying organisms
Secretes an enzyme into the dead organism to help break it down to eat (decomposers)
Some are unicellular (yeasts) and some are multicellular (mushrooms)
Example: molds
A Tree of Life
Domain Eukarya: “Protists”
Unicellular eukaryotes
Paraphyletic group -- can be divided into five clades
Most are unicellular but some are multicellular (brown algae)
Some are photosynthetic and others are heterotrophic
Some display characteristics that resemble fungi, plants, or animals
Example: Malaria in mosquitoes

7. A Tree of Life Domain Eukarya: Animalia
Multicellular and heterotrophic
No cell walls
Most can move about at least for some part of their life (motile)
Examples:
Mammalia -- mammals
Reptilia -- reptiles
Amphibians
Domain Eukarya: Plantae
Multicellular
Autotrophs -- photosynthesis
Cell walls made of cellulose
Nonmotile
Examples:
Angiosperms: flowering plants
Gymnosperms: cone or seed bearing plants

9. The Tree of Life