1. 18-1 Finding Order in Diversity
Classification
18-1 Finding Order in Diversity

3. Early Systems of Classification
Taxonomy – A. Branch of biology that names and groups organisms according to their characteristics and evolutionary history. B. First classification process occurred more than 2000 years ago by Aristotle. 1. Plant and animals, only! a. Animals were either land dwellers, water dweller, or air dwellers. b. Plants were grouped based on their stem differences.

4. C. . In attempt to begin organizing organisms, the classification process started by looking at the physical appearance. The names became too long and hard to remember, suggesting nothing about how the organisms were related to other organisms D. This old system became inadequate and was soon replaced. E. Carolus Linnaeus ( ) developed a 2–word naming system called the Binomial Nomenclature.

5. G. Scientific name = genus, species
F. Linnaeus assigned binomials (2 names) to over 11,000 species of plants and animals
G. Scientific name = genus, species
1. First part – genus is a group of closely related species.
ex. Bears - Ursus

6. 2. Second part – species is unique to the species within the genus.
ex. Polar– maritimus
Species within a genus should be more similar to each other than to other species. (can breed together successfully)

7. H. The first letter of the Genus is capitalized and both are written in italics.
I. Species names are in Latin so that they are the same in any language.
1. Closes communication
gaps between different countries with different languages.

8. J. His grouping of organisms went into a hierarchical system, using form and structure to categorize. K. Levels of Classification A. 7 levels, each level are called a taxon or taxonomic category.

9. 1. Phylum = animal kingdom 2. Division = plant kingdom
I. Kingdom- largest, most inclusive
A. Phylum/division – subject within a kingdom, made of several classes.
1. Phylum = animal kingdom
2. Division = plant kingdom

10. . b. Order – composed of similar families.
a. Class – composed of similar orders.
b. Order – composed of similar families.
c. Family – group of genera that share many characteristics.
d. Genus – group of closely related species.
e. Species – group of similar organisms that can breed. .

13. L. Subspecies – zoologists refer to variations of a species that occur in different geographic areas. 1. The Latin name is then written as: Genus species subspecies

14. Using a Dichotomous Key
A dichotomous key is used as a step method in identifying organisms.
By following the 2 step method, you can identify organisms that you may not ordinarily know.
You start at 1a always, if the clue is a YES you follow the directions to it’s right.
If the clue is a NO you go to 1b.