1. Chapter 18
Classification

2. 1. Scientific names to identify species must refer to one and only one species and everyone must use the same name for that species.

3. Canis lupus Anarrhichas lupus
What do the following two organisms have in common?
Can you identify an organism from just the species name?

4. 2. Latin or Greek names are used to name species.

5. 3. Dichotomous Key: is a tool used to help find the scientific name of a species. It is constructed using contrasting characteristics to divide the organisms in the key into smaller and smaller groups; each time a choice is made, a number of organisms are eliminated.

7. 4. Swedish botanist, Carolus Linnaeus, developed the two word naming system, binomial nomenclature, for organisms in 1730.

8. 5. In binomial nomenclature, each species is assigned a two-part scientific name.

9. 6. To properly write a scientific name, capitalize the first letter of the first word, and write second word in all lowercase. You would then underline both words.

10. 7. When typing a scientific name, italicize the two words, capitalize the first letter of the first word; the second word should be all lowercase.

11. 8. The first word of the scientific name of any species is the genus name. A genus is a group of closely related species. Genera is the plural form of the word genus.

12. 9. The second word of the scientific name is the species name.
It refers to the fact that these organisms can interbreed and produce fertile offspring.
The species name may refer to a description of an important trait or the organism’s habitat.

14. 10. In a useful classification system, organisms in a particular group are more similar to one another than they are to organisms in other groups.

15. 11. Systematics is the study of the diversity of life and the evolutionary relationships between organisms.

16. 12. The goal of systematics is to organize living things into groups that have biological meaning.

17. 13. The groups used to organize and classify those living things are called taxa ; taxon (singlular).

18. 14. Taxonomy - branch of biology that identifies, names, and classifies species based on their morphology and behavior

19. 15. The original Linnaean system of classification organized species into taxa that formed a hierarchy or set of ordered ranks.

21. 16. A hierarchy is an arrangement of items in which the items are represented as being "above", "below", or "at the same level as" one another.

22. Silly sentence to remember taxons
Dreamy
King
Phillip
Could
Only
Find
Good
Students

23. 17. Over time, Linnaeus’s original classification system expanded to include seven hierarchical taxa: species, genus, family, order, class, phylum, and kingdom.

24. 18. The two smallest categories are genus and species
18. The two smallest categories are genus and species. A genus will contain several species.

25. 19. A larger category called a family is a group of similar genera that share many similarities. (513)

26. 20. A larger category than a family is called an order (513)
20. A larger category than a family is called an order (513). An order will contain a group of closely related families.

27. 21. The next larger rank is called a class (514)
21. The next larger rank is called a class (514). A class contains a group of closely related orders.

28. 22. Classes are grouped into a phylum (phyla; plural) (514)
22. Classes are grouped into a phylum (phyla; plural) (514). A phylum includes organisms that are different but share important characteristics.

29. 23. The largest and most inclusive of Linnaeus’s taxonomic categories is the kingdom (514)

30. 24. Modern systematists apply Darwin’s ideas to classification and try to look beyond simple similarities and differences to ask questions about evolutionary relationships.

31. There are problems with the Linnaeus system of taxonomy-
Species change over time
Some species have tremendous variation
Doesn’t account for
extinct species
Doesn’t consider
organisms that
reproduce asexually
Some different species can interbreed and produce fertile offspring.

32. 18.2 Modern Evolutionary Classification
1. Phylogeny (516) is the evolutionary history of a species.

33. 2. The goal of phylogenetic systematics, or evolutionary classification, is to group species into larger categories that reflect lines of evolutionary descent, rather than overall similarities and differences.

34. 3. Phylogenetic systematics places organisms into higher taxa whose members are more closely related to one another than they are to members of any other group.

35. The larger a taxon is, the farther back in time all of its members shared a common ancestor.

36. 4. Classifying organisms using evolutionary histories places them into groups called clades.
A clade is a group of species that includes a single common ancestor and all descendants of that ancestor---living and extinct. (516)

37. 5. Clades are different from Linnaean taxa because they must be a monophyletic group (516). A monophyletic group includes a single common ancestor and all of its descendants.

38. 6. A paraphyletic group is a group that includes a common ancestor but excludes one or more groups of descendants. (516)

39. 7. Cladistic analysis compares carefully selected traits to determine the order in which groups of organisms branched off from their common ancestor.

40. 8. A cladogram links groups of organisms by showing how evolutionary lines, or lineages, branched off from common ancestor.

41. 9. A node is a branched point on a cladogram
9. A node is a branched point on a cladogram. It indicates a speciation event, in which one ancestral species splits into two new species.

42. 10. The bottom, or root of a cladogram represents the common ancestor shared by all of the organisms in the cladogram.

43. 11. Cladistic analysis also differs from Linnaean taxonomy because it focuses on derived characters when assigning organisms into clades.

44. 12. A derived character (518) is a trait that arose in the most recent common ancestor of a particular lineage and was passed along to its descendants.

46. 13. In general, the more derived genetic characters two species share, the more recently they shared a common ancestor and the more closely they are related in evolutionary terms.

47. 18.3 Building the Tree of Life
1. The six-kingdom system of classification includes the kingdoms Eubacteria, Archaebacteria, Protista, Fungi, Plantae, and Animalia.

48. 2. A domain (525) is a taxonomic category which is larger and more inclusive than a kingdom. It was established after scientists had discovered more about bacteria over time.

49. 3. The tree of life shows current hypotheses regarding evolutionary relationships among the taxa within the three domains of life.

50. 4. There are three domains: Bacteria, Archaea,
and Eukarya.

51. 5. Members of the Domain Bacteria (525) are unicellular and prokaryotic. Their cell walls contain a substance called peptidoglycan.

52. 6. There is only one kingdom in the Domain Bacteria
6. There is only one kingdom in the Domain Bacteria. That kingdom is called Eubacteria.

53. 7. Domain Archaea (526) consists of unicellular, prokaryotic cells like Domain Bacteria.

54. The difference between the two Domains is that Archaea live in extreme environments like hot springs, brine pools, and black organic mud devoid of oxygen.
Extremophiles

55. Another difference is that their cell walls do not contain peptidoglycan.

56. 8. Archaebacteria is the only kingdom in Domain Archaea.

57. 9. The Domain Eukarya (526) consists of all organisms that have a nucleus. There are four kingdoms in this domain.

58. 10. “Protists” are a kingdom under Linnaean system but they are known as a valid clade when we consider the evolutionary history of these organisms. That is why there are quotations around the word protist.

59. 11. Protists are known as the kingdom that contains organisms that don’t quite fit in any other kingdom. Some are plant like, animal like, and fungi like. Some are unicellular and others are multicellular. Some are autotrophic and others are heterotrophic.

60. 12. The kingdom Fungi are heterotrophic and contain chitin in cell walls. They do not eat their food, instead they excrete digestive enzymes onto their food and then they absorb the food.
Mushrooms are
multicellular and yeasts
are unicellular.

61. 13. Members of the kingdom of Plantae are autotrophic with cell walls that contain cellulose. Plants are also non motile, meaning they can’t move from place to place.

62. 14. Members of the kingdom Animalia are multicellular and heterotrophic. There are no cell walls in animal cells and animals are motile.