TAXONOMY

Unit 4 – Microbiology

HANDS-ON ORGANIZING PASTA (10-12 MIN)

• 6 pieces of pasta• Devise a scheme to group them based on their

shared characteristics • At each criteria, offer only 2 options to further

split the group of pasta (see exemplar)

DICHOTOMOUS KEY A step-by-step guide to help identify an organism Follows a series of YES/NO questions that will lead you

to the organism’s name

How many branches at each Yes/No question?Just 2

DICHOTOMOUS KEY EXAMPLES

ibis

heron

spoonbill

cardinal

eagle

HOW DO WE ORGANIZE LIVING THINGS?

We name all organisms using many names: K ingdom King P hylum Phillip C lass Cried O rder Out F amily “For G enus Goodness S pecies Sakes!”

Come up with your ownmemory trick!

Each level is called a “taxa”

specific

SIX KINGDOMS

Unicellular single-cell Multicellular many cells Prokaryotic no nucleus present in cells Eukaryotic nucleus present in cells

All Living Things

Domain Bacteria

Domain Archaea

Domain Eukarya

Kingdom Bacteria

Kingdom Archaea

Kingdom Protista

Kingdom Fungi

Kingdom Plantae

Kingdom Animalia

Three Domains and Six Kingdoms Classification System

CLADOGRAMS Cladogram the family tree for all living

things that describes phylogenetic (evolutionary) relationships

How do we figure out how organisms are related? Look for homologies

(common characteristics)!

Dichotomous keys: Classifying based on

presence/absence oftraits (yes/no questions)

Traditional Taxonomic Systems

Binomial nomenclature (Two-part name)Genus speciesGenus name capitalized; species in lower casealways italicized if typed, or underlined if

handwritten

Carolus Linnaeus (Li-nay-us)(1707-1778), a Swedish naturalist•created rules for classification based on organism shared characteristics:

The Binomial SystemBlack bear Ursus AmericanusGrizzly bear Ursus horribilis

What can be said about 2 species having the same genus?

The same genus name indicates that these two species are closely related in anatomy, embryology and evolutionary ancestry.

Taxonomic Classification of Grey Wolf- an example

Becoming more specific

Modern taxonomy and PhylogenyPhylogeny = the study of the evolutionary

relatedness between and among species

Family Tree Phylogenetic tree(also cladogram)

Commonancestor

Goi

ng b

ack

in ti

me

1. Which organisms in the above cladogram have hard shelled eggs?2. Which organisms in the cladogram have a backbone?3. Which shared a common ancestor most recently – a bird and a crocodile

or bird and a monkey?

HOW TO BUILD A CLADOGRAMhttp://ccl.northwestern.edu/simevolution/obonu/cladograms/Open-This-File.swf

17

DO PRACTICE FOR DICHOTOMOUS KEY

Use a dichotomous key to identify creatures on planet Pamishan

Review

1. Which group is more specific, order or class? Order2. What is meant by binomial nomenclature? A two name system (Genus species)3. List the 6 kingdoms in order from primitive to advanced Bacteria, Archaea, protista, fungi, plants, and animals

Review

4.  Which of the following pairs is MOST closely related?

 Acer rubrum  &  Acer  saccharumAcer rubrum  &  Chenopodium rubrum

5.  The science of classification is called _____________

Taxonomy

RECAP: TAXONOMY KEY WORDS

Kingdom, Phylum, Class, Order, Family, Genus, Species

Taxon (plural: taxa) Unicellular, multicellular Prokaryotic, eukaryotic Taxonomy Cladogram Phylogeny / phylogenetic Homology / homologies / homologous Dichotomous key