Chapter 17 Taxonomy

History of Taxonomy Biologists use a classification system to group organisms in part because organisms are numerous and diverse. Biologists use a classification system to group organisms in part because organisms are numerous and diverse. Taxonomy is the branch of biology that names and groups organisms according to their characteristics and evolutionary history. Taxonomy is the branch of biology that names and groups organisms according to their characteristics and evolutionary history. It was first proposed by Aristotle in 350 BC. He only had 2 groups 1) Plants & 2 )Animals. It was first proposed by Aristotle in 350 BC. He only had 2 groups 1) Plants & 2 )Animals. Who came up with an organized classification system? Who came up with an organized classification system? Carolus Linnaeus Carolus Linnaeus Used an organism’s morphology (shapes) Used an organism’s morphology (shapes)

Levels of Classification Dumb King Phillip Came Over for Grape Soda Dumb King Phillip Came Over for Grape Soda Domain Domain Kingdom Kingdom Phylum Phylum Class Class Order Order Family Family Genus Genus Species Species

Binomial Nomenclature In Linnaeus’s system, the species name has two parts In Linnaeus’s system, the species name has two parts The first part of the name is the genus The first part of the name is the genus The second part is the species identifier The second part is the species identifier This system of two-part names is known as binomial nomenclature This system of two-part names is known as binomial nomenclature The genus name is capitalized The genus name is capitalized Both names are underlined or written in italics Both names are underlined or written in italics

To classify organisms, taxonomists consider the phylogeny (evolutionary history) of the organism To classify organisms, taxonomists consider the phylogeny (evolutionary history) of the organism By concentrating on morphology, Linnaeus focused on features that are largely influenced by genes and that are clues of common ancestry. By concentrating on morphology, Linnaeus focused on features that are largely influenced by genes and that are clues of common ancestry.

Modern Phylogenic Taxonomy Systematics organizes living things in the based on evolution Systematics organizes living things in the based on evolution A phylogenic tree shows the evolutionary relationships among organisms A phylogenic tree shows the evolutionary relationships among organisms To develop a phylogenic tree taxonomists must consider To develop a phylogenic tree taxonomists must consider the fossil record the fossil record morphology morphology embryological patterns of development embryological patterns of development chromosomes and macromolecules chromosomes and macromolecules

A species is a group of individuals agreeing in form, habit, & offspring. Ernst May defined a species as a group of actually or potentially interbreeding natural populations that are reproductively isolated from other such groups. Species typically produce fertile offspring. A species is a group of individuals agreeing in form, habit, & offspring. Ernst May defined a species as a group of actually or potentially interbreeding natural populations that are reproductively isolated from other such groups. Species typically produce fertile offspring.

Cladistics Cladistics uses certain features of organisms, called shared derived characteristics, to establish evolutionary relationships Cladistics uses certain features of organisms, called shared derived characteristics, to establish evolutionary relationships A derived character is a feature that evolved only within the group under consideration A derived character is a feature that evolved only within the group under consideration Ancestry diagrams made by cladistic analysis are called cladograms Ancestry diagrams made by cladistic analysis are called cladograms

A cladogram is a tree-like diagram showing evolutionary relationships.  Any two branch tips sharing the same immediate node are most closely related A cladogram is a tree-like diagram showing evolutionary relationships.  Any two branch tips sharing the same immediate node are most closely related

3 Domains Domain Bacteria – All eubacteria Domain Bacteria – All eubacteria Domain Archaea – All archaebacteria Domain Archaea – All archaebacteria Domain Eukarya – All eukaryotes – protists, fungi, plants, & animals Domain Eukarya – All eukaryotes – protists, fungi, plants, & animals

Six-Kingdom Classification The six-kingdom classification we will study includes Archaebacteria, Eubacteria, Protista, Fungi, Plantae, and Animalia The six-kingdom classification we will study includes Archaebacteria, Eubacteria, Protista, Fungi, Plantae, and Animalia

Archaebacteria Unicellular prokaryotes Unicellular prokaryotes No peptidoglycan in cell walls No peptidoglycan in cell walls Many live in harsh environments (hot springs, salty lakes or anaerobic environments) Many live in harsh environments (hot springs, salty lakes or anaerobic environments) Believed to be similar to some of the first organisms on Earth. Believed to be similar to some of the first organisms on Earth. Some are autotrophs (make their own food), and some are heterotrophs (do not make their own food) Some are autotrophs (make their own food), and some are heterotrophs (do not make their own food)

Eubacteria Unicellular prokaryotes Unicellular prokaryotes Peptidoglycan in cell walls Peptidoglycan in cell walls Most of the bacteria you know (good and bad) Most of the bacteria you know (good and bad) Most are aerobic (use O 2 to breathe), but some are anaerobic (do not use O 2 to breathe) Most are aerobic (use O 2 to breathe), but some are anaerobic (do not use O 2 to breathe) Some are autotrophs, and some are heterotrophs Some are autotrophs, and some are heterotrophs

Protista The unicellular eukaryotes that aren’t Fungi, Plantae, or Animalia The unicellular eukaryotes that aren’t Fungi, Plantae, or Animalia They are subdivided as Fungus-like, Plant-like, or Animal-like They are subdivided as Fungus-like, Plant-like, or Animal-like Includes autotrophs and heterotrophs Includes autotrophs and heterotrophs

Fungi Eukaryotes Eukaryotes Unicellular and multicellular Unicellular and multicellular Cell walls made of chitin Cell walls made of chitin CANNOT MAKE THEIR OWN FOOD CANNOT MAKE THEIR OWN FOOD

Plantae Multicellular eukaryotes Multicellular eukaryotes All except a few parasitic forms are photosynthetic – does that make them autotrophs or heterotrophs? All except a few parasitic forms are photosynthetic – does that make them autotrophs or heterotrophs? Cell walls made of cellulose Cell walls made of cellulose

Animalia Eukaryotes Eukaryotes Multicellular Multicellular Heterotrophs Heterotrophs Most have symmetrical body organization Most have symmetrical body organization

Dichotomous Keys A tool to identify organisms is called a dichotomous key. A tool to identify organisms is called a dichotomous key. It is made from pairs of contrasting characteristics (e.g., has wings/does not have wings). It is made from pairs of contrasting characteristics (e.g., has wings/does not have wings).

Wacky People Key 1a Two feet2 1b Some other number of feet3 2a Does not look at all human4 2b Looks a lot like a human5 3a One leg6 3b Three or four legs7 4a Fly-likeMosk Cara 4b Not fly-like8 5a Seems to be a girlRita Nita 5b Not a girl9 6a Leg is curled, two feetRu-ela.Brella 6b Leg is straight, one footGiggles 7a Three legs10 7b Four legs11 8a Has webbed feetHex Oculate 8b Clawed feet12 9a Curly hair, no toesLugio Wirum 9b Wiggly looking mouth, three toes on feetC. Nile 10a Very long nose, open mouthElle E. Funk 10b Some other appearance13 11a Has duck bill, two pinchersTri D. Duckt 11b No arms or pinchers14 12a Has ears, tail, and beakGrif Leon 12b Four eyes on stalksEggur Ondy 13a One eye, webbed feetCue Kide 13b Four stalked eyes, four pinchersQuadrumenox 14a Three toed feet, nose like a flowerTunia petalos 14b Spider-like, has spotsPatterned mulywumpus

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