1. Classifying Organisms

2. Tree of Life
Organizes all living things into related relationships through
Related form
Related function
Related evolution
Always changing and being modified with new organisms

3. Organization of organisms
Domains
Kingdom
Phylum
Class
Order
Family
Genus
Species
D - K – P – C – O – F – G – S (Pneumonic device)

4. 3 Domain System Bacteria Archaea Eukarya
** Primarily separated by composition of cell wall**

5. 3 Domains Archaea Bacteria Unicellular - unicellular
prokaryotic (no nucleus)
No peptidoglycan in cell wall
Many live in environments that have no oxygen
Bacteria
- unicellular
- prokaryotic (no nucleus)
- peptidoglycan in cell wall
- Live in diverse environments

6. 3 Domains
Open books to 459, fill 3 characteristics for each Kingdom
Eukarya
Consists of 4 Kingdoms
Protista
Plantae
Fungi
Animalia

7. Organization using Cladograms
Shows evolutionary relationships
Contains current organisms and common ancestors
Shows derived traits between organisms
Identifies the out group = most basic organism (least amount of changes)

8. Cladogram Example Current Organism Out group Common Ancestor
Derived Trait

9. Classification and Evolution

10. Similarities between organisms
List three ways we classify organisms
Similar form
Similar function
Similar evolutionary history
Sometimes body structures can provide missing evidence for common ancestors

11. Specific ways we classify
Homologous Body Structures
Vestigial Organs
Analogous Body Structures
DNA and RNA sequences (molecular clocks)

12. Homologous Body Structures – body parts that appear different but arose from similar evolutionary histories

13. Why use homologous body structures to classify?
Shows a change over time from a common ancestor
Shows how the organisms have adapted to live in its environment
A change in structure is not a choice yet rather a chance happening that helped the organism in its environment

14. Unimportant Homologous Body Structures
Although they have nearly no function, they do show a link to a common ancestor
Vestigial organ – traces of homologous organs in other species

15. Vestigial Organs
Describe a vestigial organ/part in your body.

16. Analogous Body Structures
Look at the following pictures. Describe 3 similar characteristics shared between the two.
Shark
Dolphin

17. breaths air through lungs
Dolphin
skeleton bone
breaths air through lungs
horizontal fin
nurses young
skin has hair
Shark
skeleton cartilage
oxygen from gills
vertical tail
Analogous Body Structure – body parts that appear similar but arise from separate evolutionary histories

18. Using body structures to classify
Although similar, a shark and dolphin not closely related (do not share a recent common ancestor)
Similar does not always equal same
Convergent Evolution – organisms evolve similar structures independently, often due to similar environments

19. DNA and RNA sequences (molecular clocks)
Uses differences in DNA/RNA sequences to show evolutionary history
More closely related species have more similar DNA/RNA sequences
Neutral Mutations accumulate within specific area at the same rate

20. DNA and RNA sequences (molecular clocks)
Tracing neutral mutations backwards through time can help estimate time since the most recent common ancestor A B C
Leads to