Unit 1: Organization of Life Chapter 9 Classification Unit 1: Organization of Life Chapter 9

“Where can I find…?”

The Importance of Classification In biology, the practice of naming and classifying organisms is called taxonomy We classify organisms to make recognition and description easier In order to better understand the organisms of Earth, Biologists organize them into groups

What would happen if we did not have a system of classifying organisms? Mountain Lion? Puma? Cougar? Panther? WHO AM I? Felis concolor

Who do we have to thank for this? Swedish biologist Carl Linnaeus (in the 1750’s) developed the naming system we use today His two word system is called binomial nomenclature His system was based on physical and structural similarities of organisms

Naming Rules Homo sapiens The two-word naming system of binomial nomenclature is now called a scientific name Scientific names must follow rules! They are made up of two Latin or Latin-like terms They must be italicized (typing) or underlined (writing) The first word (genus) must be capitalized and the second word (species) must not! Homo sapiens

The Linnaean System Linnaeus made more than just a naming system; he made a system to classify all organisms that were known during his time The Linnaean system of classification groups organisms at successive levels of hierarchy based on similarities in their form and structure The eight basic levels of modern classification are: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

Organisms that look alike and successfully Kingdom Phylum Class Order Family Genus Species Organisms that look alike and successfully interbreed belong to the same species A group of similar species that have similar features and are closely related. A group of similar genera, each sharing similar characteristics The smallest group is the species, one or more species with similar characteristics make-up a genus, one or more genera with common traits compose a family, a group of families that share traits make up an order, orders with common characteristics compose a class, classes make up a phylum, and a Kingdom contains one or more phyla Each of these categories is referred to as a TAXON or TAXA is plural. Each Taxon contains sub groups of the smaller taxa that have something in common. Let’s take a look at cats – cats, lions, leopards, etc. A lynx and a mountain lion do not belong to the same genus as domestic cats, lions and leopards this is because their jaws contain 30 teeth and the lynx and bobcat’s jaws contain 28 teeth. They do however belong to the same family. All Cats within the family of Felidae share certain characteristics – short faces, small ears, forelimbs with five toes and hind limbs with four toes. Is a taxon of similar families Is a taxon of similar orders Is a group of similar classes A group of similar phyla or divisions

For Example HUMANS Domain Eukarya Kingdom Animalia Phylum Chordata Class Mammalia For Example Order Primates Family Hominidae Genus Homo Species sapiens

Traditional Systematics Scientists traditionally used similarities in appearance and structure to group organisms

Traditional Systematics This approach caused problems, though - why? Some groups look similar but turn out to be distantly related Some groups look different and turn out to be closely related Scientists no longer simply use similarities in appearance and structure to group organisms

Phylogenetics & Cladistics Phylogeny is the evolutionary history of a species A cladogram is a diagram that assumes phylogenies (relationships) by comparing shared characteristics How to build a cladogram

Types of Cladograms

Shared by the Following Organisms Shared Feature Shared by the Following Organisms Bach Beethoven Chopin Handel Mozart Schubert Tchaikov-sky Vivaldi Antenna Eyes Split Antenna Segmented Body Leg-Like Appendages Tongue Jointed Leg-Like Appendages Tail X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X

Bach Tchaikovsky Vivaldi Chopin Schubert Beethoven Handel Mozart Tail Jointed Leg-Like Appendages Tongue Leg-Like Appendages Segmented Body Split Antenna Eyes Antenna

Tchaikovsky Vivaldi Mozart Chopin Bach Schubert Beethoven Handel Tail Jointed Leg-Like Appendages Tongue Leg-Like Appendages Segmented Body Split Antenna Eyes Antenna