Chapter 18 Classification (p.508 - 535)

1. Chapter 18 Classification(p.508 - 535) 2013-2014

2. 18.1 Essential Questions • Why do scientists classify organisms? Objectives: • Describe the goals of binomial nomenclature • Explain the difference between a common name and a scientific name

3. DO NOW 1. Which frog below is the green frog? 2. Which one is it: Puma, Panther, Cougar, Mountain Lion?

4. I. 18.1: Finding Order in Diversity A. Assigning Scientific Names 1. The problem of common (vernacular) names a. People in different places use different words to describe the same organism b. Different organisms from different continents can have the same common name

5. c. Over 1.3 million organisms described on the planet with an estimated 5-10 million more not described d. In order to study the diversity of life, scientists needed a universal system

6. Early Classification • Aristotle • animals classified based on whether they had blood or not • Plants classified based on how they grew

7. Early Renaissance Guess the animal being described…. Today: Apis mellifera

8. 2. Binomial Nomenclature a. 1730’s – Carolus Linnaeus developed the system called binomial nomenclature • Swedish botanist • Known as the father of taxonomy

9. b. Every species is given a two part name called a scientific name • Scientific names include genus and species • The genus name is always capitalized and goes in front • Species names are written in lowercase and are unique to each species Heloderma horridum Genus Species

10. Scientific names are written in italics • Ex: Polar Bear = Ursus maritimus , Brown Bears are Ursus arctos

11. Some Genus and species Names You May Already Know Panthera leo Boa constrictor Tyrannosaurus rex Homo sapiens

12. 3. Classifying Species into Larger Groups a. Systematics – the science of naming and grouping organisms b. Organisms that are more similar to one another are placed in similar groups c. Groups are called taxa (singular taxon)

14. Analogy: Kingdom - Country Phylum - state Classes – county Orders – towns Families – neighborhood Genus - street Species – specific house

15. Kingdom:Animalia Phylum: Chordata Class:Mammalia Order:Primates Family:Hominidae Genus:Homo Species: sapiens Where do we fit in?

16. Kingdom:Animalia Phylum:Chordata Class:Reptilia Order:Squamata Family:Viperidae Genus:Bothriechis Species:schlegelii Kingdom:Animalia Phylum:Chordata Class:Reptilia Order:Squamata Family:Boidae Genus:Corallus Species:caninus

17. 4. Problems with Traditional Classification a. Linnaeus grouped taxa based on specific traits b. Many of his groups are still used today c. The difficulty is deciding which traits should be used to define a group

18. Ex: Barnacles and Limpets d. Today we look for evolutionary relationships to group organisms

19. Activity • Groups of 3-4 individuals • Develop a classification system similar to Linnaeus’s system • Create a name for each level of classification in your system • Minimum of 4 levels • Group your items according to your system • Write down or draw a brief schematic of your system on a lined sheet of paper

20. 18.1 Essential Questions • Why do scientists classify organisms? Objectives: • Describe the goals of binomial nomenclature • Identify the 7 traditional taxonomic groups

21. Do Now Questions (Day 2) 1. What is the goal of binomial nomenclature? 2. Who was Carolus Linnaeus? 3. What is a scientific name? Give an example. 4. List from most general to most specific the 7 major classification levels.

22. 18.2 Essential Question • How do evolutionary relationships effect how scientists classify organisms? Objectives: • Describe how to make and interpret a cladogram • Explain the use of DNA sequences in classification

23. II.  18.2 Modern Evolutionary Classification A. Evolutionary Classification 1. Common Ancestors a. Phylogeny – the study of how living and extinct organisms are related b. Used to groups species into larger taxa

24. 2. Clades a. Clades- are a group of species that includes a single common ancestor and all of its descendents b. Includes both living and extinct organisms

25. c. All clades are monophyletic • Monophyletic group- a group that includes a single common ancestor and all of its descendents • Class Reptilia is not monophyletic, so in evolutionary classification reptiles are not a true group

26. B. Cladograms 1. Traits are carefully selected for use in comparing in evolutionary classification 2. These traits determine where different organisms branched off from a common ancestor 3. Cladogram – a diagram that shows relationships among species and larger taxa

27. 4. Building Cladograms a. Cladograms look like trees with branches b. The point where each branch splits off is called a “node” = speciation event

28. 5. Derived Characters a. Defined- a trait that arose in the most recent common ancestor of an evolutionary line and was passed on to its descendents

29. b. Ex: having 4 limbs is a derived character in clade Tetrapoda • All tetrapods have 4 limbs

30. having hair is a derived character for clade Mammalia • all mammals have hair, but having 4 limbs is not a derived character for mammals • If it were only mammals would have this trait

31. 6. Lost Traits a. Sometimes descendents lose their derived character b. Ex: snakes are members of clade Tetrapoda, yet they have no limbs

32. 7. Clades and Traditional Taxonomic Groups a. Some traditional taxonomic groups are also true clades • Ex: class Mammalia is the same as clade Mammalia

33. b. Some traditional groups are not true clades • Ex: Birds and Reptiles are placed into separate classes in the traditional system • Reptilia is not a clade without birds since they share common ancestry • Birds belong to 3 clades: Aves, Dinosauria, and Reptilia

34. C. DNA in Classification 1. Genes as Derived Characters a. The more similar the genes in two organisms are, the more recently they shared a common ancestor b. When doing these comparisons, genes and mutations can be used as derived characters

35. 2. New Techniques Redraw Old Trees a. DNA analysis is making the evolutionary “tree of life” more accurate The tree of life includes all three domains of life. There are so many taxa that the tree has to be drawn in a circle

36. b. Ex: DNA evidence has helped to classify Giant Pandas • Red and Giant Pandas share many traits • DNA analysis shows that red pandas share more recent ancestry with raccoons • Giant Pandas share more recent ancestry with bears Cladogram Construction Link

37. 18.2 Essential Question • How do evolutionary relationships effect how scientists classify organisms? Objectives: • Describe how to make and interpret a cladogram • Explain the use of DNA sequences in classification

38. Do Now Questions (Day 3) 1. What is the goal of evolutionary classification? 2. What is a cladogram? 3. Give an example of a derived character. 4. How are DNA sequences used in classification?

39. 18.3 Essential Question • What are the six kingdoms of life and how are they arranged into the “tree of life”?

40. III. 18.3: Building the Tree of Life A. Changing Ideas about Kingdoms 1. Classification systems will continue to change as long as new evidence is continued to be found. a. Linnaeus’s system had only 2 kingdoms- plants and animals b. Technology and greater understanding of evolutionary relationships has lead to today’s system

41. c. From the late 1800’s until fairly recently, the number of kingdoms had expanded to five d. Today we have 6 kingdoms

42. 2. Three Domains a. Genetic studies have shown that there are two major and distinct groups of bacteria b. Domain- is a larger, more general classification group, just above kingdom c. The 3 Domains • Bacteria • Archaea • Eukarya

43. B. The Tree of Life 1. Domain Bacteria a. Kingdom: Eubacteria b. Basic traits • Single celled • Prokaryotes- no nucleus • Thick cell walls made up of peptidoglycan • Live in many environments • Some are parasites • Some are photosynthetic

44. 2. Domain Archaea a. Kingdom: Archaebacteria b. Basic traits • Single celled prokaryotes • Have unusual cell membranes • Have cell walls made of different material than bacteria • Live in extreme environments

45. 3. Domain Eukarya a. Contains all of the kingdoms of organisms that have nucleated cells b. Kingdom: Protista • Very diverse group, but not a true clade • Most are single celled organisms • Some are multicellular- Ex: brown algae • Some are photosynthetic and others are heterotrophic

46. c. Kingdom: Fungi • Heterotrophic • Most feed on dead organisms- release enzymes that digest food outside of their “body”, the digested food is then absorbed • Have cell walls made of chitin • Most are multicellular, some are single celled • Ex: yeasts, mushrooms

47. d. Kingdom: Plantae • Are autotrophs = photosynthetic- can make their own food • Cell wall made up of cellulose • Most are multicellular • green algae have recently been included within this kingdom • Ex: includes all flowers, ferns, and mosses

48. e. Kingdom: Animalia • Multicellular • Do not have cell walls • Are heterotrophic • Most can move from place to place

49. Careers that use this “stuff” • Zoologist/Taxonomist • Nature Show hosts • Plant/Animal Breeders • Pet Store employees and owners • Wine/Beer makers • Doctors/Pathologists/Veterinarians • Zookeepers • Horticulturists • Landscapers

50. 18.3 Essential Question • What are the six kingdoms of life and how are they arranged into the “tree of life”?