1. Phylogeny & Systematics
Understanding the Tree of Life

2. An Introduction to Nomenclature and Classification
Classification Systems:
Assign a name to each organism
Place into groups with similar traits & evolutionary histories
The Linnean Classification System:
Developed binomial nomenclature
Gave organisms a 2-part name

3. Canis familiaris (dog) GENUS SPECIES NAME (group belongs to) (Latin description of a characteristic) Canis = canines familiaris = common Ursus arctos (Grizzly bear) Ursus = bear, arctos = Northern Acer rubrum (red maple) Acer = maple, rubrum = red

4. Process of Taxonomy Linneaus’ System
Groups organisms to assigned TAXA (singular TAXON)
Process called TAXONOMY
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

5. A Taxonomic Example Canis Familiaris
Domain = Eukarya (eukaryotes) Kingdom = Animalia (animals) Phylum = Chordata (spinal cord) Class = Mammalia (mammals) Order = Carnivora (carnivores) Family = Canidae Genus = Canis Species = familiaris

6. A simple phylogenetic tree

7. Phylogeny & Systematics Defined
Phylogeny: Evolutionary history of a species or group of species often use the fossil record to “map out” connections
Systematics: Analysis of diversity & relationships between organisms. May include:
- morphology (how organisms look)
- biochemical similarities
- similarities in DNA

8. How do we use the Fossil Record?
Use placement of organisms within the various layers of sediments
Limitations… an incomplete record of true organism diversity

9. Layers in Time… Sediments settle at bottom of oceans, rivers, etc
Fossils are formed in each layer
Sea floor is pushed upward to form mountain ranges & eroded material exposes strata/fossils

10. Homologies & Analogies
Homologous structures
Analagous structures
In difference species that serve different functions but came from the SAME ancestral parts
Similar in appearance & function but came from DIFFERENT ancestors
Examples:
- bird vs insect
- fish vs whale
* Also called convergent evolution

11. Homologous Structures
Analagous Structures
Homologous Structures

12. Cladogram
Clade: A group of species that includes an ancestral species plus all its descendants
The analysis of how species are grouped in clades is called CLADISTICS
Cladogram shows evolutionary history of specific traits & shared characteristics without a focus on the rate of evolutionary change

13. Phylogenetic Tree
Phylogenetic Trees represent relative patterns of evolutionary branching
An Ultrametric Tree will include data corresponding to the actual time of evolutionary events

14. Molecular Clocks
Based on the principle that some genes/genomes evolve or mutate at a constant rate
Can estimate the date of evolutionary events that can’t be determined accurately in the fossil record
For example…
DNA: more closely related organisms are, the closer their genetic code will be
Cytochrome C: protein found in most organisms (differences in this protein due to mutation… close ancestry = few differences)