Life On Earth Do Now: Scientists estimate that there may be as many as 100,000,000 different species of organisms on Earth. Of these, about 1 x 107 have been identified. What % of species have not been identified? Do Now: Scientists estimate that there may be as many as 100,000,000 different species of organisms on Earth. Of these, about 1 x 107 have been identified. What % of species have not been identified?

Classifying Life Biologists classify organisms in two major ways: – Morphology = the structures and characteristics of organisms – Phylogeny = the evolutionary history and relationships of organisms “morph” = “form” “phylo” = “type, kind, race, or tribe”

Morphological Classification Example Mollusks are animals that have an organ called a mantle that makes a shell. Organisms with one shell are called gastropods, organisms with a double shell are called bivalves. gastropod bivalve

Phylogenetic Classification Example These bacteria are all unicellular prokaryotes. The tree shown classifies the species according to DNA similarity The more similar the DNA of two species is, the more recently they shared a common ancestor.

The Modern Classification Scheme The picture at right shows the classification scheme used to group similar organisms together. Notice how each group is made up of many of the smaller groups below it. In other words, as you go down the picture, the groups are more specific and include less organisms

Hierarchy: An arrangement of items into groups “above,” “below,” or “at the same level as” other groups.

Hierarchy Example: Many Classes Make up One Phylum The phylum chordata includes all animals that have backbones There are many different classes of animals that have backbones, like class rodentia (rodents), class primates, etc. etc.

Taxonomy = The practice of classification Taxonomy is the process or study of classification. A biological taxonomist is a scientist who specializes in classifying organisms

Taxonomy Activity Your group will receive 11 items classified in the family junkus. Your job is to divide family junkus into several genera (genuses). Each genus can then be divided into 1 or more “species” of organism

Things To Include in Your Report Unique “scientific names” of each “species.” – Should be “latin.” – Each must be unique – Scientific names include genus and species. Example: “Pencilum reddus.” A tree diagram showing the relationships of the genuses and species. Answers to questions – complete independently!