CLASSIFICATION Why Classify?

INQUIRY ACTIVITY 1) Construct a table with six rows and six columns. Label each row with the name of a different fruit. 2) Observe each fruit and choose four characteristics by which you can tell the fruits apart. Label the columns in your table with these four characteristics. Fill out the chart. 3) Record a description of each fruit in your table. Questions: What characteristics did you use to describe the fruits? Based on your table, which fruits are more closely related? Explain.

DICHOTOMOUS KEYS  A tool that is used to determine the identity of items in the natural world  Keys consist of a series of choices that lead to the correct name of a given item  “Dichotomous” means “divided into two parts,” so dichotomous keys always give two choices in each step

PRACTICE  Make a dichotomous key using the following items:  Bicycle, Automobile. Rock, Tree, Flower, Human, Dog, Pillow, Book, Shark, Bacteria, Pigeon

TAXONOMY  Science of describing, classifying, and naming organisms

HISTORY  Aristotle : First person to develop a classification system  Used for more than 2,000 years  Classified organisms as plants or animals and then was divided further based on where they lived

HISTORY  Carolus Linnaeus: 1750’s Swedish scientist considered founder of modern taxonomy  Uses observations as basis of classification system  Places organisms into groups based on similar observable features such as shape and structure  Came up with binomial nomenclature  Two-word naming system  Genus species

LINNAEUS  Linnaean system of classification consists of a hierarchy of groupings, called taxa (singular taxon)  Taxa range from kingdom (largest and most inclusive) to species (smallest and most exclusive)  Kingdom, Phylum, Class, Order, Family, Genus, Species  Species are organisms that are similar enough to produce fertile offspring together

SIX KINGDOMS  Eubacteria  Archaebacteria  Protista  Fungi  Plantae  Animalia

SIX KINGDOMS Kingdoms EubacteriaArchaebacteriaProtistaFungiPlantaeAnimalia # of Cells unicellular Most unicellular, some multicellular Most multicellular, some unicellular multicellular Nucleus?? prokaryotic eukaryotic Nutrition auto/heterotroph heterotroph (absorption) autotrophheterotroph

DOMAINS  Major change to Linnaean system was the addition of a new taxon called domain (1990).  Taxon that is larger and more inclusive than the kingdom  Three domains of life on Earth:  Bacteria  Archaea  Eukaryota

EVOLUTIONARY CLASSIFICATION  After Darwin published theory of evolution in 1800s, scientists looked for a way to classify organisms that showed phylogeny  The evolutionary history of an organism, or how it has changed over time  Cladogram : diagram that shows the evolutionary relationship among a group of organisms  Constructed using derived characters  Characteristics that appear in recent parts of a lineage but not in its older members

EVOLUTIONARY CLASSIFICATION  Genes of many organisms show important similarities at the molecular level.  Similarities in DNA can be used to help determine classification and evolutionary relationships

BIG IDEAS  How are living things organized for study?  Describe the system for naming species that Linnaeus developed.  What are the seven taxonomic categories of Linnaeus’s classification system?  Rank taxa in order starting with largest and ending with smallest