Taxonomy: Classification of Organisms

LEARNING OBJECTIVE 1 Define taxonomy & evolution Define taxonomy & evolution Explain why the assignment of a scientific name to each species is important for biologists Explain why the assignment of a scientific name to each species is important for biologists Gophers & Turtles Gophers & Turtles Camminalcules Project Camminalcules Project

KEY TERMS TAXONOMY TAXONOMY Science of describing, naming, and classifying organisms Science of describing, naming, and classifying organisms EVOLUTION EVOLUTION The change in the inherited characteristics of biological populations over successive generations.inheritedcharacteristics biologicalpopulations generations Evolutionary processes give rise to diversity at every level of biological organization, including species, individual organismslevel of biological organizationspeciesindividual organisms

Scientific Names Biologists use scientific names to precisely identify organisms Biologists use scientific names to precisely identify organisms Each organism has only one scientific name Each organism has only one scientific name Avoids confusion of many common names Avoids confusion of many common names Gophers & Turtles Gophers & Turtles

LEARNING OBJECTIVE 2 Identify the biologist who originated the binomial system of nomenclature Identify the biologist who originated the binomial system of nomenclature Describe the general scheme of the system Describe the general scheme of the system

KEY TERMS BINOMIAL NOMENCLATURE BINOMIAL NOMENCLATURE System for giving each organism a two-word scientific name System for giving each organism a two-word scientific name First used consistently by Carolus Linnaeus First used consistently by Carolus Linnaeus

Linnaeus

Binomial Nomenclature Species Species The basic unit of classification The basic unit of classification The scientific name of each species has two parts: The scientific name of each species has two parts: generic name (genus) generic name (genus) specific epithet (species) specific epithet (species) Eg. Homo sapiens Eg. Homo sapiens

Tradescantia virginiana

LEARNING OBJECTIVE 3 List and describe the hierarchical groupings of classification List and describe the hierarchical groupings of classification

Classification Hierarchical groups (most to least inclusive) Hierarchical groups (most to least inclusive) domain domain kingdom kingdom phylum phylum class class order order family family genus genus species species D i d K i n g P h i l i p C o m e O v e r F o r G r a n d m a ’ s S o u p

Classification of Ginger

(b) Each taxonomic level is more inclusive than the one below it. For example, the order Zingiberales consists of 5 families. The family Zingiberaceae contains 49 genera 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 Protist a Animal ia Fungi Eubact eria Fungi

A 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 roundGarbanzo bean 1b.Bean elliptical or oblongGo to 2 2a.Bean whiteWhite northern 2b.Bean has dark pigmentsGo to 3 3a.Bean evenly pigmentedGo to 4 3b.Bean pigmentation mottledPinto bean 4a.Bean blackBlack bean 4b.Bean reddish-brownKidney bean Dichotomous Key for Beans 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 4 Define systematics Define systematics Describe the cladistic approach to systematics Describe the cladistic approach to systematics

KEY TERMS SYSTEMATICS SYSTEMATICS Scientific study of the diversity of organisms and their natural (evolutionary) relationships Scientific study of the diversity of organisms and their natural (evolutionary) relationships A systematist seeks to reconstruct phylogeny A systematist seeks to reconstruct phylogeny

KEY TERMS PHYLOGENY PHYLOGENY Evolutionary history of a species or other taxonomic group Evolutionary history of a species or other taxonomic group MONOPHYLETIC MONOPHYLETIC Said of a group consisting of organisms that evolved from a common ancestor Said of a group consisting of organisms that evolved from a common ancestor

KEY TERMS CLADISTICS CLADISTICS Classification of organisms based on recency of common ancestry rather than degree of structural similarity Classification of organisms based on recency of common ancestry rather than degree of structural similarity

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

KEY TERMS CLADOGRAM CLADOGRAM A diagram that illustrates evolutionary relationships based on the principles of cladistics A diagram that illustrates evolutionary relationships based on the principles of cladistics

Building a Cladogram

Characters TAXON Moss Fern Pine Daisy VASCULAR TISSUESSEEDSFLOWERS A P P PPP P AA A A A Fig (1), p. 358

Moss (a) All of the plant groups shown here except mosses have vascular PineDaisyFern Node 1 Common plant ancestor Common ancestor with vascular tissues Fig. 18-7a, p. 358

MossPineDaisyFern Node 1 Common plant ancestor Common ancestor with vascular tissues Node 2 (b) Seeds are a shared character for all plant groups shown here except mosses and ferns. Fig. 18-7b, p. 358

MossPineDaisyFern Node 1 Common plant ancestor Common ancestor with vascular tissues Node 2 Node 3 Common seed- producing ancestor (c) Of the plant groups shown here, only the daisy produces flowers. Fig. 18-7c, p. 358

LEARNING OBJECTIVE 5 List and briefly describe the three domains and six kingdoms recognized by many biologists List and briefly describe the three domains and six kingdoms recognized by many biologists

KEY TERMS DOMAIN BACTERIA DOMAIN BACTERIA Domain of metabolically diverse, unicellular, prokaryotic organisms Domain of metabolically diverse, unicellular, prokaryotic organisms

KEY TERMS DOMAIN ARCHAEA DOMAIN ARCHAEA Domain of unicellular, prokaryotic organisms adapted to extreme conditions (such as very hot or very salty environments) Domain of unicellular, prokaryotic organisms adapted to extreme conditions (such as very hot or very salty environments)

KEY TERMS DOMAIN EUKARYA DOMAIN EUKARYA Includes all eukaryotic organisms (protists, plants, fungi, and animals) Includes all eukaryotic organisms (protists, plants, fungi, and animals)

The Three Domains

Domain Bacteria Domain Archaea Domain Eukarya Common ancestor of all living organisms Fig. 18-9, p. 360

Six-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 Kingdoms

BacteriaArchaeaProtistaPlantaeProtistaAnimaliaFungi Common ancestor of all living organisms Common ancestor of all eukaryotes Fig. 18-8, p. 360

LEARNING OBJECTIVE 6 Summarize the scientific limitations of the kingdom Protista Summarize the scientific limitations of the kingdom Protista

KEY TERMS PARAPHYLETIC PARAPHYLETIC Said of a group consisting of a common ancestor and some, but not all, of its descendants Said of a group consisting of a common ancestor and some, but not all, of its descendants

Kingdom Protista Ideally, all members of a kingdom should have a common ancestor Ideally, all members of a kingdom should have a common ancestor Members of kingdom Protista are paraphyletic Members of kingdom Protista are paraphyletic Some biologists think protists should not be grouped in a single kingdom Some biologists think protists should not be grouped in a single kingdom