The Classification of Living Things

The Classification of Living Things Taxonomy: - The science of classifying organisms Purpose: - To identify organisms - To represent relationships among them

History of Classification • Aristotle • 4th century B.C.E. • Grouped organisms according to habitat: • land-dwellers, water-dwellers, air-dwellers • St. Augustine • 3rd century C.E. • Classified animals us useful, harmful, or superfluous • Middle Ages • Herbalists classified plants according to what • they produced: fruit, vegetable, or wood

Carl Linnaeus (1707-1778) • Created the taxonomy ranks used to classify organism that we still use today • Each group is called a taxon (pl. taxa) • … King Phillip Came Over From Greece Singing • Used simple physical characteristics to identify new species

Carl Linnaeus Taxonomy • Classification system known as binomial nomenclature • First part is the genus; second part is the species • Uses Latin, the language of scholars in Europe at the time The genus name is always capitalized and the species name is not. A short form for the genus name may be used; Escherichia coli E. coli Domestic Cat: Felissylvestris Genus species

Classification of Humans • KINGDOM – Animalia • PHYLUM – Chordata • CLASS – Mammalia • ORDER – Primata • FAMILY – Hominidae • GENUS – Homo • SPECIES – sapiens Scientific Name: Homo sapiens

To help categorize organisms scientists use something called a DICHOTOMOUS KEY… • A system used to classify unknown organisms by using the characteristics of the organism to determine which group it should be placed based upon those characteristics.

What are These Animals?

Dichotomous Key of Animals Animals with 4 legs: Ostrich, worm, shark, man, rooster Horse, gorilla, cow

Dichotomous Key of Animals Animals with 4 legs : Horse, gorilla, cow Ostrich, worm, shark, man, rooster Animals with tail:

Dichotomous Key of Animals Animals with 4 legs: Horse, gorilla, cow Ostrich, worm, shark, man, rooster Animals with tail: Horse, cow gorilla

Dichotomous Key of Animals Animals with 4 legs: Horse, gorilla, cow Ostrich, worm, shark, man, rooster Animals with a tail: Horse, cow gorilla Animals with utters:

Dichotomous Key of Animals Animals with 4 legs: Horse, gorilla, cow Ostrich, worm, shark, man, rooster Animals with a tail: Horse, cow gorilla Animals with utters: cow horse

Tips for Classifying • Carefully observe objects to “notice” similarities and differences • Place objects into either one group or another – not both groups • Examine each group you create – to see if it can be further subdivided

Class Practice Activity • Using the “organisms” given to you by Ms. Cheyne, create a dichotomous key to separate EACH organism into its own category. • To test your key, switch with the person sitting next to you and see if they can use your key to find the names of each organism.

The Classification of Living Things