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

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

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

5 Carolus Linnaeus 1707 – th 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.

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. 6

7 Hierarchy-Taxonomic Groups Domain Kingdom Phylum Class Order Family Genus Species BROADEST TAXON Most Specific

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

Domains 9

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

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

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

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. 13

14 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. Section 2: Cladistics

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

16 Primate Cladogram