1. Taxonomy
Modern

2. How is Life Classified Today?
Taxonomy: grouping life according to shared traits
not just physical traits anymore
Morphology
Defined: studying the form and structure of organisms
Comparing the morphology (traits) of different species shows similarities and/or differences
Domain Eukarya
Kingdom Animalia
Phylum Chordata
Family Mammalia

3. Morphology Shows Non-Relationships Also!
Dolphins are not FISH!

4. How is Life Classified Today?
Homologous structures
Defined: body parts that have a similar structure, but different function
Comparing homologous structures of different organisms can show relationships
Conclusion: similar structures shows relationships

5. How is Life Classified Today?
Biochemical evidence
Comparing DNA, RNA, amino acids, & proteins
Similarities and differences can be found
DNA mutates at known rates
More time that has passed = more mutations
Conclusion: Organisms with similar DNA are more closely related

6. How is Life Classified Today?
Chromosome Evidence
Chromosomes of different species are examined for similarities and differences (size, shape, color bands)
Ex Above: human, orangutan, gorilla, pygmy chimp
Conclusion: Similar organisms have chromosome similarities

7. How is Life Classified Today?
Embryo Development
Blastula (ball of cells) forms early in development
Blastopore (small indentation) begins to form digestive system
Blastopore develops into the anus of some animals and mouth of others
Conclusion: Similar development indicates relationship
Blastula
Blastopore

8. Which two organisms are more closely related to one another?
In both humans and starfish, the blastopore becomes our anus….
In insects, the blastopore becomes their mouth.

9. Cladograms
Defined: branching diagram used to show evolutionary relationships
Try to group life according to similar traits
Phylogeny: Evolutionary history of an organism
Q: List 2 characteristics of a salamander.
Q: From the diagram, which organism is most closely related to the Chimp?

10. Silly example of a cladogram

11. 1) What does an amphibian & crocodile have in common?
Vertebrae, Bony skeleton, Four limbs
2) List the traits of a ray-finned fish.
Doesn’t have 4 limbs, has bony skeleton, has vertebrae

15. ReView
What is morphology and how can it be used to help classify organisms?
What are homologous structures and how is it used to help classification?
How can molecular evidence like DNA and chromosomes be used to classify life?
What does it mean if two different organisms develop along similar pattern? Different patterns?
Examine the cladogram on the next slide to answer a few more questions.

16. 5a) List the traits of organism 4
5a) List the traits of organism 4. 5b) What does organism 2 and 5 have in common? 5c) Which trait separates organism 1 from the rest?