1. Classification and The Tree of Life
Unit 1: Chap 25-26

2. Classification/Taxonomy
Carolus Linnaeus
Swedish botanist and anatomist
Taxonomy: ordered division of organisms into categories based on a set of characteristics used to assess similarities and differences.
Not based on evolutionary relationships but resemblance

3. Binomial nomenclature
Common names (monkey, fish) refer to more than 1 species.
A 2 part scientific name (binomial) was created by Linnaeus
1. Genus: to which the species belongs
2. Specific epithet: unique for each species within the genus
Ex: Leopard = Panthera pardus

4. Hierarchical Classification
Species are placed into groups belonging to more comprehensive groups.

5. Classification+evolutionary history
= Phylogeny
Phylogenic trees: branching diagram that represents a hypothesis about evolutionary relationships.
Constructed from a series of dichotomies, 2 way branch points; divergence of 2 species from a common ancestor.
• It is a hypothesis. •

6. Phylogeny + Shared Characteristics
Cladogram: diagram depicting patterns of shared characteristics among species.
Clade: within a tree, a group of species that includes an ancestral species and all its descendants
Cladistics: analysis of how species are grouped

7. Cladogram

8. Cladistics: 1. Monophyletic: single tribe
- Ancestral species and ALL descendants
2. Paraphyletic: result of lack of information on clade members
- Ancestral species and SOME descendants
3. Polyphyletic: several species that lack a common ancestor

9. Homologous VS Analogous
Structures in different species that are similar because of a common ancestry.
Similarity between 2 species due to convergent evolution rather than to descent from a common ancestor with the same trait.

10. Phylograms
Length of a branch reflects the number of changes in a specific DNA sequence in that lineage.
Different lengths but all lineages have survived for the same number of years.
Indicates that a given gene evolves at slightly different rates in the different lineages.

11. Ultrametric Trees
Same branching as a phylogram but all branches are of equal length.
Branches reflect measurements of geological time.

12. History of Taxonomic Systems
2 Kingdom: plant (fungi, bacteria) and animal (protozoans)
5 Kingdoms: Monera, Protista, Plantae, Fungi, Animalia (Eukaryotes/Prokaryotes)
Finally:
3 Domain System: Bacteria, Archaea, Eukarya (Plants, Animals, Fungi)
- level higher than Kingdom

13. 3 Domain System