1. Unit 2 - Microbiology 2.1 Taxonomy Kingdoms Phylogeny

2. Taxonomic Systems  Carl Linnaeus created rules for assigning names to plants and animals 250 years ago: Binomial nomenclature Two names Genus species (always italicized if typed, or underlined if handwritten)

3. Species  A species is a group of living organisms that look alike and can only breed with members of their own species to produce a viable offspring

4. The Binomial System  Black bear Ursus Americanus  Grizzly bear Ursus horribilis  The same genus name indicates that these two species are closely related in anatomy, embryology and evolutionary ancestry.

5. Levels of Classification  There are seven main levels or taxa: Kingdom phylum class order family genus species

6. Examples of classifying organisms with levels of taxa:

7. Classifying organisms with levels of Taxa

8. The Species for each example:  Taraxacum officinale Common name = Dandelion  Homo sapiens Common name = Human  Musca domestica Common name = Housefly  Escherichia coli Common name = ?? We use E. coli

9. Six Kingdom Classification System 1.Eubacteria 2.Archaebacteria 3.Protista 4.Fungi 5.Plantae 6.Animalia

11. Phylogeny  Most scientists believe that organisms have evolved over time – changed so much that they become new species.  Relationships are shown in a type of diagram called a phylogenetic tree, where the tree starts from the most ancestral form and includes branchings that lead to all of its descendents.

13. Dichotomous Key  A dichotomous key is constructed so that a series of choices must be made, and each choice leads to a new branch of the key.  If choices are made accurately, the end result is the name of the organism being identified.  A well-constructed key helps us to identify known species. E.g. when you are on a nature walk.

14. 2 types of dichotomous keys: same result

15. Review 1. Which group is more specific, order or class?  Order 2. What is meant by binomial nomenclature?  A two name system (genus species) 3. List the 6 kingdoms in order from primitive to advanced  Archaebacteria, eubacteria, protista, (fungi, plants, and animals)