1. SB3c: Examine evolutionary basis of modern Classification.

2. Jabberwock

3. Why do we classify living things?
We have about 1.5 million NAMED & classified species.
There may be over 30 million species on Earth!!
We organize so we can communicate, share information & find information.

4. Taxonomy …branch of biology for naming & grouping of organisms
Organisms can be grouped according to:
their characteristics
their evolutionary history

5. A Brief History of Taxonomy
Aristotle – had 2 groups, plants & animals
Linnaeus – developed a Hierarchy of levels, according to morphology (physical appearance)

6. Problems with using morphology to classify
Some things may look different but still be a member of the same species.
Injuries or other events may alter the physical appearance
Some things look alike but are not related (dolphins & fish)

7. How closely are these beetles related?

8. Hierarchy of taxonomy

9. Binomial Nomenclature
…is the ”2 part scientific name” of an organism RULES 1) 1st word = genus name, always capitalize 1st letter 2) 2nd word = species name, all lower case 3) italicized or underlined 4) Written in Latin

10. Binomial Nomenclature Example
Homo sapien = humans
Hyla squirella= squirrel treefrog
P. leo = lion

11. Phylogeny
...classifying organisms according to their evolutionary history A phylogenetic tree can be created using systematics (aka, taxonomy.)

13. How does systematics work?
Use evidence from many sources: 1) fossils 2) morphology (physical appearance) 3) embryological development 4) chromosomes & DNA

14. Cladograms
…branching diagrams that show the evolutionary history between organisms.
Systematics uses derived characters to make cladograms
The more derived characters an organism shares the more closely related they are.