Taxonomy: Classification of Taxonomy: Classification of OrganismsOrganisms

LEARNING OBJECTIVE 1LEARNING OBJECTIVE 1

• Define Define taxonomy & evolutiontaxonomy & evolution

• Explain why the assignment of a Explain why the assignment of a scientific name to each species is scientific name to each species is important for biologistsimportant for biologists

• Gophers & TurtlesGophers & Turtles• Camminalcules ProjectCamminalcules Project

KEY TERMSKEY TERMS

• TAXONOMYTAXONOMY • Science of describing, naming, and classifying Science of describing, naming, and classifying

organismsorganisms

• EVOLUTIONEVOLUTION• The change in the inherited characteristics of

biological populations over successive generations.

• Evolutionary processes give rise to diversity at every level of biological organization, including species, individual organisms

Scientific NamesScientific Names

• Biologists use scientific names to precisely identify Biologists use scientific names to precisely identify organisms organisms

• Each organism has only one scientific name Each organism has only one scientific name

• Avoids confusion of many common namesAvoids confusion of many common names

• Gophers & TurtlesGophers & Turtles

LEARNING OBJECTIVE 2LEARNING OBJECTIVE 2

• Identify the biologist who originated the Identify the biologist who originated the binomial systembinomial system of nomenclature of nomenclature

• Describe the general scheme of the Describe the general scheme of the system system

KEY TERMSKEY TERMS

• BINOMIAL NOMENCLATUREBINOMIAL NOMENCLATURE • System for giving each organism a two-word System for giving each organism a two-word

scientific namescientific name • First used consistently by Carolus LinnaeusFirst used consistently by Carolus Linnaeus

LinnaeusLinnaeus

Binomial NomenclatureBinomial Nomenclature

• SpeciesSpecies• The basic unit of classificationThe basic unit of classification

• The scientific name of each species has The scientific name of each species has two parts: two parts: • generic name (genus) generic name (genus) • specific epithet (species)specific epithet (species)

•Eg. Homo Eg. Homo sapienssapiens

Tradescantia virginianaTradescantia virginiana

LEARNING OBJECTIVE 3LEARNING OBJECTIVE 3

• List and describe the hierarchical List and describe the hierarchical groupings of classificationgroupings of classification

ClassificationClassification

• Hierarchical groups (most to least inclusive)Hierarchical groups (most to least inclusive)• domaindomain• kingdom kingdom • phylum phylum • class class • order order • family family • genus genus • speciesspecies

Did King Philip Come Over For

Grandma’s Soup

Classification of GingerClassification of Ginger

(b) Each taxonomic level is more inclusive than the onebelow it. For example, the order Zingiberales consistsof 5 families. The family Zingiberaceae contains 49genera and a total of about 1300 species.

Eukarya

Plantae

Anthophyta

Monocotyledones

Zingiberales

Zingiberaceae

Zingiber(ginger genus)

48 other genera

4 other families

18 other orders

1 other main class

9 other phyla

5 other kingdoms

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Fig. 18-5b, p. 356

Protista

Animalia

Fungi

Eubacteria

Fungi

A Dichotomous KeyA Dichotomous Key

Organized set of couplets of mutually exclusive characteristics of biological organisms. 

Identifying beans using a dichotomous key. Use the key to identify the beans depicted here.Black Bean, Garbanzo Bean, Kidney Bean, Pinto Bean, White Northern Bean

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

     

3a. Bean evenly pigmented Go to 4

3b. Bean pigmentation mottled Pinto bean

     

4a. Bean black Black bean

4b. Bean reddish-brown Kidney bean

Dichotomous Key for Dichotomous Key for BeansBeans

Once a characteristics applied, it cannot be represented in the future samples.

Identifying beans using a dichotomous key. Use the key to identify the beans depicted here.

Garbanzo bean

White northern Pinto beanBlack bean

Kidney bean

LEARNING OBJECTIVE 4LEARNING OBJECTIVE 4

• Define Define systematicssystematics

• Describe the cladistic approach to Describe the cladistic approach to systematicssystematics

KEY TERMSKEY TERMS

• SYSTEMATICSSYSTEMATICS • Scientific study of the diversity of organisms Scientific study of the diversity of organisms

and their natural (evolutionary) relationshipsand their natural (evolutionary) relationships• A systematist seeks to reconstruct A systematist seeks to reconstruct phylogenyphylogeny

KEY TERMSKEY TERMS

• PHYLOGENYPHYLOGENY • Evolutionary history of a species or other Evolutionary history of a species or other

taxonomic grouptaxonomic group

• MONOPHYLETICMONOPHYLETIC • Said of a group consisting of organisms that Said of a group consisting of organisms that

evolved from a common ancestorevolved from a common ancestor

KEY TERMSKEY TERMS

• CLADISTICSCLADISTICS • Classification of organisms based on recency Classification of organisms based on recency

of common ancestry rather than degree of of common ancestry rather than degree of structural similaritystructural similarity

CladisticsCladistics

• Cladists emphasize phylogeny by focusing Cladists emphasize phylogeny by focusing on when evolutionary lineages (lines of on when evolutionary lineages (lines of descent) divide into two branches descent) divide into two branches

• Cladists develop Cladists develop cladogramscladograms

KEY TERMSKEY TERMS

• CLADOGRAMCLADOGRAM • A diagram that illustrates evolutionary A diagram that illustrates evolutionary

relationships based on the principles of relationships based on the principles of cladisticscladistics

Building a CladogramBuilding a Cladogram

Characters

TAXON

Moss

Fern

Pine

Daisy

VASCULAR TISSUES SEEDS FLOWERS

A

P

P

P P P

P

A A

A

A

A

Fig. 18-7 (1), p. 358

Mo

ss

(a) All of the plant groups shown here except mosseshave vascular

Pin

e

Dai

sy

Fer

n

Node1

Common plantancestor

Common ancestorwith vascular tissues

Fig. 18-7a, p. 358

Mo

ss

Pin

e

Dai

sy

Fer

n

Node1

Common plantancestor

Common ancestorwith vascular tissues

Node2

(b) Seeds are a shared character for all plant groupsshown here except mosses and ferns.

Fig. 18-7b, p. 358

Mo

ss

Pin

e

Dai

sy

Fer

n

Node1

Common plantancestor

Common ancestorwith vascular tissues

Node2

Node3

Commonseed-producingancestor

(c) Of the plant groups shown here, only the daisyproduces flowers.

Fig. 18-7c, p. 358

LEARNING OBJECTIVE 5LEARNING OBJECTIVE 5

• List and briefly describe the three List and briefly describe the three domainsdomains and six and six kingdomskingdoms recognized recognized by many biologists by many biologists

KEY TERMSKEY TERMS

• DOMAIN BACTERIADOMAIN BACTERIA • Domain of metabolically diverse, unicellular, Domain of metabolically diverse, unicellular,

prokaryotic organismsprokaryotic organisms

KEY TERMSKEY TERMS

• DOMAIN ARCHAEADOMAIN ARCHAEA • Domain of unicellular, prokaryotic organisms Domain of unicellular, prokaryotic organisms

adapted to extreme conditions (such as very adapted to extreme conditions (such as very hot or very salty environments)hot or very salty environments)

KEY TERMSKEY TERMS

• DOMAIN EUKARYADOMAIN EUKARYA • Includes all eukaryotic organisms (protists, Includes all eukaryotic organisms (protists,

plants, fungi, and animals)plants, fungi, and animals)

The Three DomainsThe Three Domains

DomainBacteria

DomainArchaea

DomainEukarya

Common ancestorof all living organisms

Fig. 18-9, p. 360

Six-Kingdom ClassificationSix-Kingdom Classification

• Kingdom Bacteria (domain Bacteria) Kingdom Bacteria (domain Bacteria) • Kingdom Archaea (domain Archaea)Kingdom Archaea (domain Archaea)• Kingdom Protista (domain Eukarya)Kingdom Protista (domain Eukarya)• Kingdom Fungi (domain Eukarya)Kingdom Fungi (domain Eukarya)• Kingdom Plantae (domain Eukarya)Kingdom Plantae (domain Eukarya)• Kingdom Animalia (domain Eukarya)Kingdom Animalia (domain Eukarya)

The Six KingdomsThe Six Kingdoms

Bacteria Archaea Protista Plantae Protista Animalia Fungi

Common ancestorof all living organisms

Common ancestorof all eukaryotes

Fig. 18-8, p. 360

LEARNING OBJECTIVE 6LEARNING OBJECTIVE 6

• Summarize the scientific limitations of Summarize the scientific limitations of the kingdom Protistathe kingdom Protista

KEY TERMSKEY TERMS

• PARAPHYLETIC PARAPHYLETIC • Said of a group consisting of a common Said of a group consisting of a common

ancestor and some, but not all, of its ancestor and some, but not all, of its descendantsdescendants

Kingdom ProtistaKingdom Protista

• Ideally, all members of a kingdom should Ideally, all members of a kingdom should have a common ancestor have a common ancestor

• Members of kingdom Protista are Members of kingdom Protista are paraphyleticparaphyletic

• Some biologists think protists should not Some biologists think protists should not be grouped in a single kingdombe grouped in a single kingdom