Table of Contents

1. Classification of Organisms Chapter 17 Table of Contents Section 1 Biodiversity Section 2 Systematics Section 3 Modern Classification

2. Section 1 Biodiversity Chapter 17 Objectives • Relatebiodiversity to biological classification. • Explainwhy naturalists replaced Aristotle’s classification system. • Identifythe main criterion that Linnaeus used to classify organisms. • Listthe common levels of modern classification from general to specific.

3. 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.

4. 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.

5. 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 kingdom, phylum, class, order, family,genus, and species.

6. Section 1 Biodiversity Chapter 17 Classification Hierarchy of Organisms

7. Section 1 Biodiversity Chapter 17 Linnaeus’s Levels of Classification Click below to watch the Visual Concept. Visual Concept

8. 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.

9. Section 2 Systematics Chapter 17 Objectives • Identifythe kinds of evidence that modern biologists use in classifying organisms. • Explainwhat information a phylogenetic diagram displays. • Statethe criteria used in cladistic analysis. • Describehow a cladogram is made. • Discusshow proteins and chromosomes are used to classify organisms. • Explaincladistic taxonomy, and identify one conclusion that is in conflict with classical taxonomy.

10. 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.

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

12. Section 2 Systematics Chapter 17 Phylogeny Click below to watch the Visual Concept. Visual Concept

13. 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.

14. Section 2 Systematics Chapter 17 Cladistics • Cladisticsuses shared, derived characters as the only criterion for grouping taxa.

15. Section 2 Systematics Chapter 17 Cladogram: Major Groups of Plants

16. Section 2 Systematics Chapter 17 Cladistics, continued • Molecular Cladistics • Molecular similarities (such as similar amino acid or nucleotide sequences), as well as chromosome comparisons, can help determine common ancestry.

17. Section 2 Systematics Chapter 17 Cladistics, continued • Chromosomes • Analyzing karyotypes can provide more information on evolutionary relationships.

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

19. Section 2 Systematics Chapter 17 Cladistics Click below to watch the Visual Concept. Visual Concept

20. Section 2 Systematics Chapter 17 Phylogenetic Diagram of Mammals

21. 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.

22. 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.

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

24. 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.

25. 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.

26. 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.

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

28. Section 3 Modern Classification Chapter 17 Six Kingdoms

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