Classification

How do we classify? Make observations Choose defining characteristics Group by those characteristics Divide groups into subgroups by characteristics Continue dividing until each is in its own group

Why do we classify? Large numbers of objects get very confusing unless they are sorted (prevent confusion) By grouping similar things we can predict patterns (patterns help us make predictions) We can put definite limits on the area of study It helps us discover and point out relationships between objects

Examples of Classification Periodic Table- We can get more information about the elements as they are arranged in the periodic table then if they were listed by alphabetical order

Classification of Organisms Classification is the arrangement of organisms into orderly groups based on their similarities Classification is also known as taxonomy Taxonomists are scientists that identify & name organisms

Benefits of Classifying Accurately & uniformly names organisms Prevents misnomers such as starfish & jellyfish that aren't really fish Uses same language (Latin or some Greek) for all names Sea”horse”?? copyright cmassengale

Confusion in Using Different Languages for Names copyright cmassengale

Latin/Greek Genus species names are Understood by all Taxonomists copyright cmassengale

copyright cmassengale Standardized Naming Binomial nomenclature: Two names for every organism :Genus species Write Genus first, species second Capitalize Genus, lowercase species Italicized in print Underline when writing Names describe characteristics of the organism in Latin or Greek Turdus migratorius American Robin copyright cmassengale

Binomial Nomenclature Which TWO are more closely related? copyright cmassengale

Classification Groups Taxon ( taxa-plural) is a category into which related organisms are placed There is a hierarchy of groups (taxa) from broadest to most specific Kingdom, Phylum, Class, Order, Family, Genus, species copyright cmassengale

copyright cmassengale King Phillip Called Out Fifty Good Soldiers! copyright cmassengale

copyright cmassengale

copyright cmassengale Taxons Most genera contain a number of similar species The genus Homo is an exception (its only living members are modern humans) Classification is based on evolutionary relationships copyright cmassengale

In one order, there are many species   Order Family Genus Species

Which of these are in the same species? Genus? Kingdom? German shepherd Poodle Wolf Fox Human Venus flytrap

copyright cmassengale Dichotomous Keying Used to identify organisms Characteristics given in pairs Read both characteristics and either go to another set of characteristics OR identify the organism copyright cmassengale

Example of Dichotomous Key 1a Tentacles present – Go to 2 1b Tentacles absent – Go to 6 2a Eight Tentacles – Octopus 2b More than 8 tentacles – 3 3a Tentacles hang down – go to 4 3b Tentacles upright–Sea Anemone 4a Balloon-shaped body–Jellyfish 4b Body NOT balloon-shaped - 5 copyright cmassengale

Rule 1 Each step is made of two parts labeled 1A and 1B, then 2A and 2B, and so on. 1a. Bean round ………………………….Garbanzo bean 1b. Bean elliptical or oblong……………………Go to 2 2a.Bean white……………………………White northern 2b.Bean has dark pigments……………………..Go to 3

Rule 2 When you start a key, your first step is to try and break the objects into two groups about the same size

Rule 3 Each step either identifies a specimen, or gives directions of the next step to go to. 2a.Bean white……………………………..White northern 2b.Bean has dark pigments…………………….…Go to 3 3a.Bean evenly pigmented……………………….Go to 4 3b.Bean pigmentation mottled……………Pinto bean

Rule 4 At each step you choose one of the choices, not both.

Rule 5 When you are writing a set of choices, it is better to use a present/absent choice because it is more inclusive. Use characteristics that are definite.

The end!