CHAPTER 18 CLASSIFICATION BIOLOGY CHAPTER 18 CLASSIFICATION Photo credit: ©Gary Randall/Visuals Unlimited

18.1 Finding Order in Diversity   Classification – grouping of objects or information based on similarities Taxonomy – branch of biology for grouping and naming organisms

Assigning Scientific Names Scientific Names are written in Latin because: The language is no longer used The words stay the same and cannot change since the language is dead The words only have one meaning

Early efforts at naming organisms Aristotle Developed the first method of classification Grouped them into 2 groups: plants and animals His system was useful but did not group organisms according to their evolutionary history

Linneaus Developed binominal nomenclature system Binominal Nomenclature – each species has a two part name – genus & species Based on structural and physical similarities of organisms He not only named species, he also grouped them into categories. Each level if called a taxon

Copyright Pearson Prentice Hall Scientists realized there were enough differences among organisms to make 5 kingdoms: Monera - bacteria Protista Fungi Plantae Animalia Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Six Kingdoms Recently, biologists recognized that Monera were composed of two distinct groups of bacteria The six-kingdom system of classification includes: Eubacteria Archaebacteria Protista Fungi Plantae Animalia Monera Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Three-Domain System Molecular analyses have given rise to a new taxonomic category that is now recognized by many scientists. The domain is more inclusive category than any other-larger than a kingdom. The three domains are: Eukarya –kingdoms protists, fungi, plants, and animals Bacteria Archaea As new information is gained about organisms in the domains Bacteria and Archaea, they may be subdivided into additional kingdoms. Copyright Pearson Prentice Hall

This diagram shows some of the ways organisms have been classified into kingdoms over the years. The six-kingdom system includes the following kingdoms: Eubacteria, Archaebacteria, Protista, Fungi, Plantae, and Animalia.

Copyright Pearson Prentice Hall Domain Eubacteria unicellular prokaryotes. Thick or thin cell walls made of peptidoglycan Ex: E. coli, cyanobacteria Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Domain Archaea unicellular prokaryotes. live in extreme environments. cell walls lack peptidoglycan, and cell membranes contain unusual lipids not found in other organisms. Ex: thermophiles, haleophiles Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Domain Eukarya Unicellular and multicellular eukaryotes This domain is organized into four kingdoms: Protista eukaryotic organisms that cannot be classified as animals, plants, or fungi. unicellular or multicellular photosynthetic or heterotrophic Live in moist environments Ex: paramecium, kelp, slime mold Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Fungi heterotrophs. Most fungi feed on dead or decaying organic matter multicellular (mushrooms) or unicellular (yeasts) some have cell wall composed of chitin do not move from place to place Ex: mushrooms, yeast, black mold Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Plantae Multicellular photosynthetic autotrophs. cannot move from place to place. cell walls composed of cellulose. includes cone-bearing and flowering plants as well as mosses and ferns Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Animalia multicellular heterotrophic. do not have cell walls. can move about complex organ systems Copyright Pearson Prentice Hall

BIO-QUIZ

18-3 Organisms whose cell walls contain peptidoglycan belong in the kingdom Fungi. Eubacteria. Plantae. Archaebacteria.

18-3 Multicellular organisms with no cell walls or chloroplasts are members of the kingdom Animalia. Protista. Plantae. Fungi.

18-3 Organisms that have cell walls containing cellulose are found in Eubacteria and Plantae. Fungi and Plantae. Plantae and Protista. Plantae only.

18-3 Molecular analyses have given rise to a new taxonomic classification that includes three domains. seven kingdoms. two domains. five kingdoms.

18-3 Which of the following contain more than one kingdom? only Archaea only Bacteria only Eukarya both Eukarya and Archaea

Eight levels of classification are… Domain – largest group of classification, a group of related kingdoms Kingdom – a group of related phyla Phylum – a group of closely related classes Class – a group of closely related orders Order – a group of closely related families Family – a group of closely related genera Genus – a group of closely related species Species most specific level of classification a group of organisms that can interbreed and produce fertile offspring

Linnaeus's System of Classification Grizzly bear Black bear Giant panda Red fox Abert squirrel Copyright Pearson Prentice Hall Coral snake Sea star Linnaeus’s hierarchical system of classification uses seven taxonomic categories. This illustration shows how a grizzly bear, Ursus arctos, is grouped within each taxonomic category. Only some representative species are illustrated for each category above the species level. Movie

BIO-QUIZ

18-1 Which statement about classification is true? Biologists use regional names for organisms. Biologists use a common classification system based on similarities that have scientific significance. Biologists have identified and named most species found on Earth. Taxonomy uses a combination of common and scientific names to make the system more useful.

18-1 Linnaeus's two-word naming system is called binomial nomenclature. taxonomy. trinomial nomenclature. classification.

18-1 Several different classes make up a(an) family. species. kingdom. phylum.

18-1 A group of closely related species is a(an) class. genus. family. order.

18-1 Which of the following lists the terms in order from the group with the most species to the group with the least? order, phylum, family, genus family, genus, order, phylum phylum, class, order, family genus, family, order, phylum

Did King Phillip Come Over For Great Spaghetti Proper way to write a scientific name All letters are lower case except the genus is capitalized. Genus and species is underlined or italicized Ex. eukarya, animalia, chordate, mammalia, primata, hominidae, Homo, sapien

Dichotomous Key A set of paired statements used to help identify organisms Read each statement and decide which fits your organism Go to where that statement tells you and read the next two statements Eventually you will reach a statement that tells you the name of the organism

Choose one of the items from the following list: pine tree, clam, rock, robin, tin can, deer, oak tree, mouse, dandelion, Paramecium, bicycle, ant 1. a. Organism is living....................................go to 4. b. Organism is nonliving........ ....................go to 2. 2. a. Object is metallic.....................................go to 3. 2. b. Object is nonmetallic................. ..............Rock. 3. a. Object has wheels..............................Bicycle. 3. b. Object does not have wheels..............Tin Can. 4. a. Organism is microscopic...........Paramecium. 4. b. Organism is macroscopic........................go to 5. 5. a. Organism is a plant.................................go to 6. 5. b. Organism is an animal............................go to 8.

6. a. Plant has a woody stem.........................go to 7. 6. b. Plant has a herbaceous stem......... .Dandelion. 7. a. Tree has needle like leaves..............Pine Tree. 7. b. Tree has broad leaves......................Oak Tree. 8. a. Organism lives on land.........................go to 9. 8. b. Organism lives in water...........................Clam. 9. a. Organism has 4 legs or fewer.............go to 10. 9. b. Organism has more than 4 legs................Ant. 10 a. Organism has fur................................go to 11. 10 b. Organism has feathers.........................Robin. 11 a. Organism has hooves............................Deer. 11 b. Organism has no hooves......................Mouse

18.2 Modern Evolutionary Classification Phylogeny – evolutionary relationships among organisms. Biologists currently group organisms into categories that represent lines of evolutionary descent, or phylogeny, not just physical similarities. The higher the level of the taxon, the further back in time is the common ancestor of all the organisms in the taxon. Organisms that appear very similar may not share a recent common ancestor.

Classification Using Cladograms Cladogram – a branching diagram showing the evolutionary relationships among a group of organisms Traits that appear in recent parts of a lineage but not in its older members are called derived traits Derived traits can be used to construct a cladogram Cladograms help scientists understand how one lineage branched from another in the course of evolution

EUBACTERIA ARCHAEBACTERIA EUKARYOTES Fig. 20.17, p. 327

BIO-QUIZ

18-2 Grouping organisms together based on their evolutionary history is called evolutionary classification. traditional classification. cladogram classification. taxonomic classification.

18-2 Traditional classification groups organisms together based on derived characters. similarities in appearance. DNA and RNA similarities. molecular clocks.

18-2 In an evolutionary classification system, the higher the taxon level, the more similar the members of the taxon become. the more common ancestors would be found in recent time. the fewer the number of species in the taxon. the farther back in time the common ancestors would be.

18-2 Classifying organisms using a cladogram depends on identifying external and internal structural similarities. new characteristics that have appeared most recently as lineages evolve. characteristics that have been present in the group for the longest time. individual variations within the group.

18-2 To compare traits of very different organisms, you would use anatomical similarities. anatomical differences. DNA and RNA. proteins and carbohydrates.