Classification and Taxonomy Ch. 26 sect. 2-3

1. Classification the grouping of objects or organisms based on a set of criteria scientist use classification to sort and group all the organisms on Earth

1. Classification I. Taxonomy the science of classifying living organisms Goal: to give organisms identity and discover relationships between organisms

1. Classification II. Developers of classification A. Aristotle Greek philosopher officially categorized organisms for the first time

1. Classification Aristotle’s System of Classification Plants herbs bushes trees Animals land air water l a n d a i r w a t e

1. Classification Limitations of Aristotle’s system: based on the belief that species do not change no place for extinct species difficult to categorize some species as land or water

1. Classification B. Polynomial nomenclature Romans named organisms using Latin terms Used long descriptive names to identify organism ex. Apis pubescens, thorace subgriseo, abdomine fusco, pedibus posticis, utrinque margine ciliates European Honeybee

1. Classification C. Carolus Linnaeus 1700’s Swedish Biologist Developed classification system based on morphology Morphology: structure or form of an organism Developed binomial nomenclature Apis mellifera European honeybee

1. Classification II. Binomial Nomenclature two part naming system uses Genus and species Genus name is always capitalized Species name is never capitalized Name is italicized or underlined when written To abbreviate first letter of the Genus (H.) and the full species name (sapien).

2. Levels of Classification Domain very broad group above kingdom 3: Bacteria, Archaea, Eukarya Kingdom broad group that is classified based on a similar feature 6: Animalia, Plantae, Fungi, Protista, Archaea, and Bacteria

2. Levels of Classification Phylum group of classes with similar features Class group of orders with common features Order group of similar families

2. Levels of Classification Family group of genera with similar features Genus group of similar species Species group of similar animals that can interbreed and produce viable offspring

3. How to identify groups Organisms can be identified using a dichotomous key a set of criteria used to identify features and identify a named organism

3. How to read a dichotomous key

Classification Levels Flip-chart Create a saying using the first letter of each level Write it on a flip chart top side saying underside actual name and description of level

Bellwork: Compare these two birds. Are they the same species? How can you tell?

4. Taxonomy I. 1700-Present species are grouped based on shared physical characteristics (morphology) ability to interbreed

Inadequacies of Linnaean System not useful for making evolutionary predictions only looks at morphology separate species can look alike, act alike, and interbreed

Inadequacies of Linnaean System artificially makes groups 3 of the 6 kingdoms are not monophyletic Protista, Archaea, and Bacteria monophyletic = having a single common ancestor

2. Taxonomy II. Modern Taxonomy Phylogenetic approach distinguishes relationships based on evolutionary history creates phylogenies to identify and name a new species

2. Taxonomy III. Phylogeny based on molecular data (ex. DNA) identifies groups more effectively group = a common ancestor and its descendents identifies when a species diverged from the common ancestor

2. Taxonomy Goals of Phylogeny to identify major clades clade = a monophyletic group to predict past evolutionary change to identify relationships between species

3. How to Read a Phylogenetic Tree Each branch represents a different group each split represents a molecular change the point of separation is the most recent common ancestor