Classification/Taxonomy Chapter 18

Why Classify? Why Classify? To study the diversity of life, biologists use a classification system to name organisms & group them in a logical manner.

Taxonomy Defined: Discipline of classifying organisms and assigning each organism a universally accepted name. In other words, naming things.

Why common names don’t work Common names vary among languages. Example: United Kingdom – Buzzard refers to a hawk United States – Buzzard refers to a vulture Red-tailed HawkHoney BuzzardTurkey Vulture

5 Aristotle 384 BC Classified organisms as either plants or animals Classified organisms as either plants or animals

Carolus Linnaeus (1707 – 1778) (1707 – 1778) Created the system of naming we use today. Created the system of naming we use today. In taxonomy, a group or level of organization is called a taxonomic category or taxon. In taxonomy, a group or level of organization is called a taxonomic category or taxon.

Binomial Nomenclature “Bi” means 2 “Bi” means 2 “nomial” means naming “nomial” means naming Nomenclature means “the system of” Nomenclature means “the system of” Defined: In binomial nomenclature, each species is assigned a two-part scientific name.

8 Binomial Nomenclature Carolus Linnaeus Carolus Linnaeus In binomial nomenclature, each species is assigned a two-part scientific name. In binomial nomenclature, each species is assigned a two-part scientific name. The scientific name is always written in italics or underlined. The scientific name is always written in italics or underlined. The first word (the genus) is capitalized The first word (the genus) is capitalized The second word (the species) is lowercased. The second word (the species) is lowercased. EX- Genus species or Genus species Humans- Homo sapien

Example of Binomial Nomenclature Polar Bear is Ursus maritimus Polar Bear is Ursus maritimus Ursus: genus Ursus: genus Ursus contains 5 other kinds of bears Ursus contains 5 other kinds of bears maritimus: species maritimus: species The Latin word, maritimus, refers to the sea. The Latin word, maritimus, refers to the sea. Polar bears often live on pack ice that floats in the sea. Polar bears often live on pack ice that floats in the sea.

10 Linnaeus's System of Classification A group or level of organization is called a taxonomic category, or taxon A group or level of organization is called a taxonomic category, or taxon Linnaeus had 7- Linnaeus had 7- Kingdom “King Phylum Phillip Class Came Order Over Family For Genus Great Species Spaghetti”

Definitions to know Genus : is a group of closely related species Genus : is a group of closely related species Species : Group of similar organisms that can breed and produce fertile offspring Species : Group of similar organisms that can breed and produce fertile offspring

Family: Group of genera that share many Family: Group of genera that share many characteristics characteristics Order: Group of similar families Order: Group of similar families Class: Group of similar orders Class: Group of similar orders Phylum: Group of closely related classes Phylum: Group of closely related classes Kingdom: Largest taxonomic group, Kingdom: Largest taxonomic group, consisting of closely related consisting of closely related phyla. phyla.

Here We Go… Polar Bear Species: maritimus Genus: Ursus Family: Ursidae Order: Carnivora Class: Mammalia Phylum: Chordata Kingdom: Animalia What do these mean?...lets see

What they mean Species: maritimus (lives in marine environment) Genus: Ursus (kind of bear) Family: Ursidae (larger category of bears) Order: Carnivora (meat-eating animals) Class: Mammalia (warm-blooded, hair, & milk) Phylum: Chordata (vertebrates) Kingdom: Animalia (there are 6 kingdoms) *Do NOT have to write*

How to remember: King Phillip Came Over For Green Salad Kingdom Phylum Class Order Family Genus Species

Rules of the Game Uniqueness: Every name has to be unique. Universality: Zoologists have adopted, by international agreement, a single language to be used on a worldwide basis. All animals are given a generic (common name) and specific name in Latin (scientific name). These names are in italics or are underlined (i.e. Homo sapiens).

Visuals

18

19 Checkpoint Questions: 1. How are living things organized for study? 2. Describe the system for naming species that Linnaeus developed. 3. What are the seven taxonomic categories of Linnaeus’s classification system? 4. Why do scientists avoid using common names when discussing organisms? 5. What is significant about members of the same species?

Taxonomy Video

If these three species belong to the same genus, they are descended from a common ancestor. Genus species Felis domestica leo margarita Sand cat` Lion Domestic Cat Felis domestica Felis leo Felis margarita

A Problem with Traditional Classification Traditional classification systems relied on Traditional classification systems relied on body structure comparisons only body structure comparisons only Due to convergent evolution, organisms that Due to convergent evolution, organisms that are quite different from each other evolve are quite different from each other evolve similar body structures. similar body structures. Convergent Evolution : Process by which unrelated organisms independently evolve similarities when adapting to similar environments.

A Problem with Traditional Classification Example: The Crab, The barnacle, & The limpet The barnacle and the limpet have similarly shaped shells & look alike The barnacle and the limpet have similarly shaped shells & look alike The crab has a very different body form The crab has a very different body form Based on anatomy, the barnacle & limpet could be classified together and the crab in a different group. Based on anatomy, the barnacle & limpet could be classified together and the crab in a different group.

Related This incorrect because crabs and barnacles are actually related

25 TRADITIONAL CLASSIFICATION CLADOGRAM AppendagesConical Shells Crab Barnacle Limpet Crab Barnacle Limpet CrustaceansGastropod Molted exoskeleton Segmentation Tiny free-swimming larva Section 18-2 Traditional Classification Versus Cladogram Go to Section:

Crustaceans Even though they do not look a like, crabs & barnacles are actually related Gastropods Molted Exoskeleton Segmentation Free swimming Larva

Evolutionary Classification Biologists now group organisms into categories that represent lines of evolutionary descent, not just physical similarities Biologists now group organisms into categories that represent lines of evolutionary descent, not just physical similarities Evolution Classification : Is the strategy of grouping organisms together based on their evolutionary history.

Classification Using Cladograms Cladogram : A diagram that shows the evolutionary relationships among a group of organisms.

Crustaceans Using Cladograms, you can see that crabs and barnacles share similar characteristics because they both molt & are segmented Gastropods Molted Exoskeleton Segmentation Free swimming Larva

Crustaceans You can also see that ALL have a free swimming larva stage Gastropods Molted Exoskeleton Segmentation Free swimming Larva

31 Modern Evolutionary Classification Modern Evolutionary Classification Similarities in DNA and RNA Similarities in DNA and RNA The genes of many organisms show important similarities at the molecular level that can be used as criteria to help determine classification. The genes of many organisms show important similarities at the molecular level that can be used as criteria to help determine classification.

32 Modern Evolutionary Classification Molecular Clocks Molecular Clocks A model known as a molecular clock uses DNA comparisons to estimate the length of time that two species have been evolving independently. A model known as a molecular clock uses DNA comparisons to estimate the length of time that two species have been evolving independently. Comparison reveals more DNA in common, the more recent the common ancestor Comparison reveals more DNA in common, the more recent the common ancestor

33 Terminology Classification Classification Assigning organisms to different catagories based on their relationship Assigning organisms to different catagories based on their relationship Taxonomy Taxonomy The science of naming organisms The science of naming organisms Systematics Systematics Determining evolutionary relationships of organisms Determining evolutionary relationships of organisms Phylogeny Phylogeny Evolutionary history Evolutionary history

34 Phylogenetic Tree Shows evolutionary relationships Shows evolutionary relationships More historical than cladogram More historical than cladogram

35 MyxozoaMyxozoa ArthropodaArthropoda AnnelidaAnnelida MolluscaMollusca LophophoratesLophophorates HemichordataHemichordata ChordataChordata OtherpseudocoelomatesOtherpseudocoelomates NematodaNematoda PoriferaPorifera CtenophoraCtenophora CnidariaCnidaria PlacozoaPlacozoa PlatyhelminthesPlatyhelminthes NemerteaNemertea CiliophoraCiliophora SarcomastigophoraSarcomastigophora MicrosporaMicrospora ApicomplexaApicomplexa MesozoaMesozoa EchinodermataEchinodermata CrustaceaCrustacea ChelicerataChelicerata UniramiaUniramia ProtochordatesProtochordates

36 Birds Mammals Reptile Amphibian Fish Four Limbs Amniotic Egg Endothermic Fur Feathers Vertebrae

37 Monophyletic A group of all the descendants of a common ancestor A group of all the descendants of a common ancestor The common ancestor is in the group The common ancestor is in the group Example: Mammalia Example: Mammalia Ancestor was a mammal like reptile

38 Paraphyletic A group of descendants of a common ancestor A group of descendants of a common ancestor Common ancestor is in the group Common ancestor is in the group Not all descendants are included Not all descendants are included Example: Reptiles Example: Reptiles Does not include birds and mammals

39 Polyphyletic A group that has some similarities A group that has some similarities Common ancestor is in not in the group Common ancestor is in not in the group Not all descendants are included Not all descendants are included Example: Flying vertebrates Example: Flying vertebrates

The Three-Domain System Recently, as evidence about microorganisms continue to accumulate, biologists came to realize that the Kingdom Monera were composed of 2 distinct groups. Recently, as evidence about microorganisms continue to accumulate, biologists came to realize that the Kingdom Monera were composed of 2 distinct groups. The 6-Kingdom system of classification includes kingdoms: The 6-Kingdom system of classification includes kingdoms: 1. Eubacteria 2. Archaebacteria 3. Protista 4. Fungi 5. Plantae 6. Animalia

6 Kingdoms Eubacteria Archaebacteria Protista Fungi Plantae Animalia E. ecoliParamecium Fern frod H. coccineaHomo sapiensPyrococcus furiosus Prokaryote Eukaryote Autotroph or heterotroph Autotroph or heterotroph Autotroph/ heterotroph Heterotroph Autotroph Most common bacteria Live in very hot places Includes Algae Don’t belong in other euk Cell walls & Chloroplasts Release enzymes to digest food No cell wall No chloroplasts Multicellular “Ancient Bacteria”

42 Cladogram Evolutionary relationship of a group of organisms Evolutionary relationship of a group of organisms Each clad (group) share something in common Each clad (group) share something in common Ancestral traits are the oldest Ancestral traits are the oldest Derived traits evolved later Derived traits evolved later

43 Cladogram for Transportation Wheels are the most ancestral Wheels are the most ancestral Wings are the most derived Wings are the most derived

44 Construct a Cladogram

45 Gorilla Four limbs Four limbs Fur Fur Lost tail Lost tail

46 Tiger Four limbs Four limbs Fur Fur Tail Tail

47 Lizard Four limbs Four limbs Tail Tail

48 Fish Tail Tail

49 Chimpanzee Four limbs Four limbs Fur Fur Lost tail Lost tail

50 Clad With 4 Limbs

51 Clad With Fur

52 Clad With No Tail

53 Characteristics for Constructing Cladogram Tail is the most ancestral Tail is the most ancestral Four limbs is the oldest derived trait Four limbs is the oldest derived trait Fur is a later derived trait Fur is a later derived trait Loss of tail is the most derived trait Loss of tail is the most derived trait

54 GorillaChimpanzee Tiger Lizard Fish Four Limbs Fur Tail Lost

55 Gorilla Tail? How do we know the gorilla lost its tail? How do we know the gorilla lost its tail?

56 Gorilla’s Vestigial Tail Gorilla Human

The End.