Classifying Organisms

1. Section 1 Biodiversity Chapter 17 Classifying Organisms • Naturalists have invented several systems for categorizing biodiversity, which is the variety of organisms considered at all levels from populations to ecosystems.

2. Section 1 Biodiversity Chapter 17 Taxonomy • Naturalists replaced Aristotle’s classification system because it did not adequately cover all organisms and because his use of common names was problematic. • Taxonomyis the science of describing, naming, and classifying organisms.

3. Section 1 Biodiversity Chapter 17 Taxonomy, continued • The Linnaean System • Carolus Linnaeus devised a seven-level hierarchical system for classifying organisms according to their form and structure. • From the most general to the most specific,the levels are domain, kingdom, phylum, class, order, family, genus, and species.

4. Section 1 Biodiversity Chapter 17 Classification Hierarchy of Organisms

5. Section 1 Biodiversity Chapter 17 Linnaeus’s Levels of Classification

6. Section 1 Biodiversity Chapter 17 Levels of Classification • Binomial Nomenclature • An important part of Linnaeus’s system was assigning each species a two-part scientific name—a genus name, such as Homo, and a species identifier, such as sapiens. • This system of a two-part name is known as binomial nomenclature.

7. Section 2 Systematics Chapter 17 Phylogenetics • A modern approach to taxonomy is systematics, which analyzes the diversity of organisms in the context of their natural relationships. • When classifying organisms, scientists consider fossils, homologous features, embryos, chromosomes, and the sequences of proteins and DNA.

8. Section 2 Systematics Chapter 17 Phylogenetics, continued • A phylogenetic diagram displays how closely related a subset of taxa are thought to be.

9. Section 2 Systematics Chapter 17 Phylogenetics, continued • Evidence of Shared Ancestry • Homologous features as well as similarities in patterns of embryological development provide information about common ancestry.

10. Section 2 Systematics Chapter 17 Similarities in Amino Acid Sequences

11. Section 2 Systematics Chapter 17 Phylogenetic Diagram of Mammals

12. Section 3 Modern Classification Chapter 17 Objectives • Describethe evidence that prompted the invention of the three-domain system of classification. • Listthe characteristics that distinguish between the domains Bacteria, Archaea, and Eukarya. • Describethe six-kingdom system of classification. • Identifyproblematic taxa in the six-kingdom system. • Explainwhy taxonomic systems continue to change.

13. Section 3 Modern Classification Chapter 17 The Tree of Life • Revising the Tree • The phylogenetic analysis of rRNA nucleotide sequences by Carol Woese led to a new “tree of life” consisting of three domains aligned with six kingdoms.

14. Section 3 Modern Classification Chapter 17 Three Domains of Life • The three domains areBacteria, Archaea, and Eukarya.

15. Section 3 Modern Classification Chapter 17 Three Domains of Life, continued • Domain Bacteria • Domain Bacteria aligns with Kingdom Eubacteria, which consists of single-celled prokaryotes that are true bacteria.

16. Section 3 Modern Classification Chapter 17 Three Domains of Life, continued • Domain Archaea • Domain Archaea aligns with Kingdom Archaebacteria, which consists of single-celled prokaryotes that have distinctive cell membranes and cell walls.

17. Section 3 Modern Classification Chapter 17 Three Domains of Life, continued • Domain Eukarya • Domain Eukaryaincludes the kingdoms Protista, Fungi, Plantae, and Animalia. • All members of this domain have eukaryotic cells.

18. Section 3 Modern Classification Chapter 17 Phylogenetic Diagram of Major Groups of Organisms

19. Section 3 Modern Classification Chapter 17 Six Kingdoms

20. Section 3 Modern Classification Chapter 17 Kingdom and Domain Characteristics

21. Chapter 17 Standardized Test Prep Multiple Choice 1. Which information is given in a species name? A. genus and order B. division and genus C. genus and species identifier D. species identifier and phylum

22. Chapter 17 Standardized Test Prep Multiple Choice, continued 1. Which information is given in a species name? A. genus and order B. division and genus C. genus and species identifier D. species identifier and phylum

23. Chapter 17 Standardized Test Prep Multiple Choice, continued 2. To which level of classification does a group of closely related species of organisms belong? F. class G. order H. genus J. kingdom

24. Chapter 17 Standardized Test Prep Multiple Choice, continued 2. To which level of classification does a group of closely related species of organisms belong? F. class G. order H. genus J. kingdom

25. Chapter 17 Standardized Test Prep Multiple Choice, continued 3. Eukaryotic organisms that have a nucleus and organelles, have a cell wall made of chitin, and secrete digestive enzymes belong to which kingdom? A. Fungi B. Plantae C. Protista D. Animalia

26. Chapter 17 Standardized Test Prep Multiple Choice, continued 3. Eukaryotic organisms that have a nucleus and organelles, have a cell wall made of chitin, and secrete digestive enzymes belong to which kingdom? A. Fungi B. Plantae C. Protista D. Animalia

27. Chapter 17 Standardized Test Prep Multiple Choice, continued 4. On the basis of this cladogram, which plants share the most recent common ancestor? F. mosses and ferns G. mosses and pine trees H. ferns and flowering plants J. pine trees and flowering plants

28. Chapter 17 Standardized Test Prep Multiple Choice, continued Complete the following analogy: 5. class : order :: kingdom : A. genus B. domain C. species D. phylum

29. Chapter 17 Standardized Test Prep Multiple Choice, continued Complete the following analogy: 5. class : order :: kingdom : A. genus B. domain C. species D. phylum

30. Chapter 17 Standardized Test Prep Multiple Choice,continued Use the diagram below to answer question 6. The diagram represents the eight levels of classification.

31. Chapter 17 Standardized Test Prep Multiple Choice, continued 6. Which level of classification represents a species? F. A G. C H. D J. G

32. Chapter 17 Standardized Test Prep Multiple Choice, continued 6. Which level of classification represents a species? F. A G. C H. D J. G

33. Chapter 17 Standardized Test Prep Short Response Consider the characteristics of members of Kingdom Protista. Explain why Kingdom Protista includes so many diverse organisms.

34. Chapter 17 Standardized Test Prep Short Response, continued Consider the characteristics of members of Kingdom Protista. Explain why Kingdom Protista includes so many diverse organisms. Answer: Protists, such as amoebas, are eukaryotes and are more complex than prokaryotes. They can be unicellular or multicellular. They can also be animal-like or plant-like.

35. Chapter 17 Standardized Test Prep Extended Response Base your answers to parts A & B on the information below. To study the biodiversity of a rain forest, researchers sometimes collect species in vast numbers. Part A How would traditional taxonomy aid a researcher who found 955 beetle species in one kind of tropical tree? Part B How could molecular phylogenetics assist that same researcher?

36. Chapter 17 Standardized Test Prep Extended Response, continued Answer: Part A The beetles would be divided into groups based on observable characters, such as form and structure. Part BBeetles would be divided into groups based on amino acid or nucleotide sequences, which could be used to separate beetle species that look very similar.