1. Ch 17:Classification
Modified from Massengale, biology junction

2. What is Classification?
Classification is the arrangement of organisms into orderly groups based on their similar characteristics.
Classification is also known as taxonomy.
Taxonomists are scientists that identify & name organisms.

3. Benefits of Classifying
Make sense and order of things.
Accurately & uniformly names organisms.
Prevents misnomers such as starfish & jellyfish that aren't really fish.
Uses same language (Latin or some Greek) for all names.
Sea”horse”??

4. Early Taxonomists 2000 years ago, Aristotle was the first taxonomist.
Aristotle divided organisms into 2 groups - plants & animals.
More organisms were discovered and did not fit into either groups.

5. Carolus Linnaeus 1707 – 1778 18th century taxonomist.
Classified organisms by their structure.
Developed naming system still used today.
An eight-level system based on shared characteristics.
Hypothesize how closely related organisms are.
More shared characteristics = more closely related.

6. The Linnaean System of Classification
Levels (also known as a taxon) of Classification
1. Domain  largest taxon.
2. Kingdom  broken into smaller groups called PHYLA.
3. Phyla/Phylum  broken into smaller groups called CLASS.
4. Class  broken into smaller groups called ORDER.
5. Order  broken into smaller groups called FAMILIES.
6. Families  broken into smaller groups called GENUS.
7. Genus are sorted into individual SPECIES.
8. Species – the smallest taxon and most specific.

7. Hierarchy-Taxonomic Groups
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
BROADEST TAXON
Genus and species are the two names used to identify specific organisms in the binomial system of classification. Division is used for plants.
Most Specific

8. Linnaeus’ classification system has seven levels.
Domain
Each level or taxon is included in the level above it.
Levels get increasingly specific from kingdom to species.

9. Domains

10. Carolus Linnaeus Called the “Father of Taxonomy”.
Developed the modern system of naming known as binomial nomenclature.
He developed a Two-word naming system (Genus & species) for an organism known as binomial nomenclature.
Also known as a Scientific Name.
Help scientist communicate clearly about living things.

11. Standardized Naming
Scientific names provide consistency amongst scientist when speaking of a specific organism.
Scientific name is unique to that specific organism.
Binomial nomenclature uses:
Genus and species
Latin or Greek
Italicized in print
Capitalize genus, but NOT species
Turdus migratorius
American Robin

12. Scientific names help scientists to communicate.
Some species have very similar common names.
Some species have many common names.

13. Section 2: Cladistics
Definition: Classification based on evolutionary relationships.
Cladogram: a diagram that shows how species might be related based on derived characteristics such as feathers, hair, or scales.
Derived characteristics - traits that some have and others don’t.
Represented on cladogram as hash marks.

14. Section 2: Cladistics
A clade is a group of species that shares a common ancestor.
Each species in a clade shares some traits with the ancestor.
Each species in a clade has traits that have changed.
Species placed in order that they descended from common ancestor.

15. Section 2: Cladistics
Nodes represent the most recent common ancestor of a clade.
FOUR LIMBS WITH DIGITS
CLADE
Tetrapoda clade 1
Amniota clade 2
Reptilia clade 3
Diapsida clade 4
Archosauria clade 5
Clades can be identified by snipping a branch under a node.
FEATHERS AND TOOTHLESS BEAKS.
SKULL OPENINGS IN FRONT OF THE EYE AND IN THE JAW
OPENING IN THE SIDE OF THE SKULL
SKULL OPENINGS BEHIND THE EYE
EMBRYO PROTECTED BY AMNIOTIC FLUID
DERIVED CHARACTER
NODE

16. Primate Cladogram