1. Classification: Organizing Life’s Diversity Taxonomy, kingdom, phylum, class, order, family. Warm-up: 1.What is it called when natural selection leads to the creation of a new species? (Yes, this again) 2.Embryology and homologous structures imply that multiple species may share what? 3.What is the name for the chart below? Speciation A common ancestor A cladogram

2. Organizing Life’s Diversity  At least 1.7 million species of living organisms have been discovered  The list grows longer every year  What should we do with them?  How are they to be classified?

3. Classification:  A. How classification begins:  1. Biologists want to better understand organisms so they organize them.  2. One tool that they use to do this is classification: a. the grouping of objects or information based on similarities.

4. Taxonomy:  The branch of biology that groups and names organisms based their different characteristics.

5. Aristotle’s System:  The Greek philosopher Aristotle (384-322 B.C.) developed the first widely accepted system of biological classification.  He classified all the organisms he knew into two groups: plants and animals.  According to his system, birds, bats, and flying insects are classified together even though they have little in common besides the ability to fly.

6. Linnaeus’s System:  In the late eighteenth century, a Swedish botanist, Carolus Linnaeus (1707-1778), developed a method of grouping organisms that is still used by scientists today.  Based on physical and structural similarities of organisms.  As a result, the groupings revealed the relationships of the organisms.

7. Linnaeus’s System  Linnaeus developed a two-word naming system called binomial nomenclature to identify species.  Each species is assigned a two part scientific name.  Scientific names are always written in italics.  The first word is capitalized and the second word is lowercase.  Homo sapiens

8. Linnaeus’s System  The first part of the scientific name is the genus.  The second part of the scientific name is the species.  Do Ursus arctos and Ursus maritimus belong to the same species or to the same genus?

9. Linnaeus’s System  Linnaeus’s hierarchical system of classification includes eight levels.  Each of these levels is called a taxon.  From smallest to largest  Species Genus Family Order Class Phylum Kingdom Domain

10. Taxonomic Categories  Kingdom (most broad) K ing  Phylum P hilip  Class C ame  Order O ver  Family F or  Genus G reen  Species (most specific) S oup

11. Linnaeus’s System  Species: organisms that look alike and successfully interbreed ; the smallest and most specific of the taxonomic categories  Domain: the largest and most inclusive of the taxonomic categories

12. Scientific and Common Names  Taxonomists are required to use Latin.  Why do scientists use Latin names for classification?  Because it is no longer used in conversation so it never changes.

15.  Which taxon contains the others? A. Order B. Class C. Genus D. Family