Presentation on theme: "Chapter 18. Why Classify? ◦ Scientists classify organisms into groups in a logical manner to make it easier to study the diversity of life. ◦ Taxonomy:"— Presentation transcript:
Why Classify? ◦ Scientists classify organisms into groups in a logical manner to make it easier to study the diversity of life. ◦ Taxonomy: The discipline of classifying organisms and assigning each a universally accepted name. Assigning Scientific Names ◦ Each species has been assigned a name for classification purposes. ◦ Binomial Nomenclature: The two part scientific naming system used in classification. The fist name is always capitalized and represents the Genus of the animal. Genus: A group of closely related animals, for example; bears The second name is specific to that type of animal.
Carolus Linnaeus: Developed binomial nomenclature. Linnaeus’s hierarchical system of classification includes seven levels. The seven layers from smallest to larges are as follows. ◦ Taxon: A group or level of organization into which organisms are classified. Species Genus Family Order Class Phylum Kingdom. Linnaeus grouped organisms based on physical similarities and he only had two kingdoms; Animalia & Plantae.
Species: A group of similar organisms that can breed and produce fertile offspring. Genus: A group of closely related species. Family: A group of genera that share many characteristics. Order: A group of similar families. Class: A group of similar orders. Phylum: A group of closely related classes. Kingdom: Large taxonomic group, consisting of closely related phyla.
Dichotomous Key: A key used to identify a plant or animal in which each stage presents descriptions of two distinguishing characters, with a direction to another stage in the key, until the species is identified.
Phylogeny: The study of evolutionary relationships among animals. Evolutionary Classification: The strategy of grouping organisms together based on their evolutionary history. Biologist group organisms based on evolutionary descent or phylogeny, not just physical characteristics. Derived characters: Characteristics that show up in recent organism lineage but not in older organisms. Cladogram: A diagram that shows evolutionary relationships.
There are six (6) kingdoms in modern classification; Eubacteria, Archaebacteria, Protista, Fungi, Plantae, and Animalia. The Three-Domain System: ◦ Modern Biologist have created a new taxonomic category called domain. ◦ Domain: is a more inclusive category and is larger than a kingdom. ◦ There are three domains: Eukarya, Bacteria, and Archaea.