1. Classifying Organisms
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.
Taxonomy is the science of describing, naming, and classifying organisms.

3. Chapter 17 Taxonomy, continued The Linnaean System
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. Classification Hierarchy of Organisms
Section 1 Biodiversity
Chapter 17
Classification Hierarchy of Organisms

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

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

9. Phylogenetics, continued
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. Similarities in Amino Acid Sequences
Section 2 Systematics
Chapter 17
Similarities in Amino Acid Sequences

11. Phylogenetic Diagram of Mammals
Section 2 Systematics
Chapter 17
Phylogenetic Diagram of Mammals

12. Chapter 17 Objectives Section 3 Modern Classification
Describe the evidence that prompted the invention of the three-domain system of classification.
List the characteristics that distinguish between the domains Bacteria, Archaea, and Eukarya.
Describe the six-kingdom system of classification.
Identify problematic taxa in the six-kingdom system.
Explain why taxonomic systems continue to change.

13. Chapter 17 The Tree of Life Revising the Tree
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. Chapter 17 Three Domains of Life
Section 3 Modern Classification
Chapter 17
Three Domains of Life
The three domains are Bacteria, Archaea, and Eukarya.

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

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

19. Section 3 Modern Classification
Chapter 17
Six Kingdoms

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

21. Chapter 17 Multiple Choice
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. Multiple Choice, continued
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. Multiple Choice, continued
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. Multiple Choice, continued
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. Multiple Choice, continued
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. Multiple Choice, continued
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. Multiple Choice, continued
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. Multiple Choice, continued
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. Multiple Choice, continued
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. Multiple Choice, continued
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. Multiple Choice, continued
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. Multiple Choice, continued
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 Short Response
Standardized Test Prep
Short Response
Consider the characteristics of members of Kingdom Protista.
Explain why Kingdom Protista includes so many diverse organisms.

34. Short Response, continued
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 Extended Response
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. Extended Response, continued
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 B Beetles would be divided into groups based on amino acid or nucleotide sequences, which could be used to separate beetle species that look very similar.