1. Introduction to Taxonomy

2. Why Classify? To study the diversity of life, biologists use a classification system to name organisms and group them in a logical manner. Copyright Pearson Prentice Hall

3. Why Classify? In the discipline of taxonomy, scientists classify organisms and assign each organism a universally accepted name. Copyright Pearson Prentice Hall

4. Assigning Scientific Names Common names of organisms vary, so scientists assign one name for each species. Always in Latin. Genus species Copyright Pearson Prentice Hall Homo sapiens

5. Assigning Scientific Names Carolus Linneaus developed a naming system called binomial nomenclature. In binomial nomenclature, each species is assigned a two-part scientific name. The scientific name is italicized. Copyright Pearson Prentice Hall Canis familiaris Felis catus

6. Linnaeus's System of Classification Linnaeus's seven levels of classification are—from smallest to largest—  species  genus  family  order  class  phylum  kingdom King Philip Came Over For Good Spagetti Copyright Pearson Prentice Hall

7. Linnaeus's System of Classification Each level is called a taxon, or taxonomic category. Species and genus are the two smallest categories. Copyright Pearson Prentice Hall Grizzly bear Black bear

8. Species  Remember that a species is a group of organisms that can mate and reproduce fertile offspring  Not a clear cut definition

9. Genus and Species  The genus name comes first and begins with a capital letter.  Ex. Felis (it can be abbreviated as F.  The species names comes second and begins with a lower case letter.  Ex. domesticus *Both the genus and species names are usually italicized and often underlined. Ex. Felis domesticus

10. Linnaeus's System of Classification Genera that share many characteristics are grouped in a larger category, the family. Copyright Pearson Prentice Hall Grizzly bear Black bear Giant panda

11. Linnaeus's System of Classification An order is a broad category composed of similar families. Copyright Pearson Prentice Hall Red fox Grizzly bear Black bear Giant panda

12. Linnaeus's System of Classification The next larger category, the class, is composed of similar orders. Copyright Pearson Prentice Hall Abert squirrel Class Mammalia Black bear Giant panda Grizzly bear Red fox

13. Linnaeus's System of Classification Several different classes make up a phylum. Copyright Pearson Prentice Hall PHYLUM Chordata Black bear Giant panda Grizzly bear Red fox Abert squirrel Coral snake

14. Linnaeus's System of Classification The kingdom is the largest and most inclusive of Linnaeus's taxonomic categories. Copyright Pearson Prentice Hall KINGDOM Animalia Black bear Giant panda Grizzly bear Red fox Sea star Abert squirrel Coral snake

15. Linnaeus's System of Classification Copyright Pearson Prentice Hall Red fox Grizzly bear Black bear Giant panda Sea star Coral snake Abert squirrel

16. Common Names  Most people use common names for organisms  This causes problems  13 lined ground squirrels are often called gophers

17. Scientific Names  Scientific names solve the naming problem  Latin is used for most scientific names.

18. Classification of a human  Kingdom = Animalia  Phylum = Chordata  Class = Mammalia  Order = Primate  Family = Hominid  Genus = Homo  Species = sapien

19. Binomial Nomenclature All organisms are given a genus and a species name. This way all people can use the same name to identify organisms

20. How do we classify organisms today?  Not so much on physical similarities (can be based too much on opinions).  Scientific evidence is a better way to do this.

21. Evidence for Classification  Chromosome Structure  Biochemical Similarities  Embryology  DNA Sequencing  Reproduction

22. Similarities in DNA and RNA The genes of many organisms show important similarities at the molecular level. Similarities in DNA can be used to help determine classification and evolutionary relationships. Copyright Pearson Prentice Hall

23. The Tree of Life Evolves Systems of classification adapt to new discoveries. Linnaeus classified organisms into two kingdoms— animals and plants. Copyright Pearson Prentice Hall

24. The Tree of Life Evolves Five Kingdoms Scientists realized there were enough differences among organisms to make 5 kingdoms:  Monera  Protista  Fungi  Plantae  Animalia Copyright Pearson Prentice Hall

25. The Tree of Life Evolves Six Kingdoms Recently, biologists recognized that Monera were composed of two distinct groups: Eubacteria and Archaebacteria. Copyright Pearson Prentice Hall

26. The Tree of Life Evolves The six-kingdom system of classification includes:  Eubacteria  Archaebacteria  Protista  Fungi  Plantae  Animalia Copyright Pearson Prentice Hall

27. The Three-Domain System Molecular analyses have given rise to a new taxonomic category that is now recognized by many scientists. The domain is a more inclusive category than any other — larger than a kingdom. Copyright Pearson Prentice Hall

28. The Three-Domain System The three domains are:  Eukarya, which is composed of protists, fungi, plants, and animals.  Bacteria, which corresponds to the kingdom Eubacteria.  Archaea, which corresponds to the kingdom Archaebacteria. Copyright Pearson Prentice Hall

29. Domain Bacteria Members of the domain Bacteria are unicellular prokaryotes. Their cells have thick, rigid cell walls that surround a cell membrane. Their cell walls contain peptidoglycan. Copyright Pearson Prentice Hall

30. Domain Archaea Members of the domain Archaea are unicellular prokaryotes. Many live in extreme environments. Their cell walls lack peptidoglycan, and their cell membranes contain unusual lipids not found in any other organism. Copyright Pearson Prentice Hall

31. Domain Eukarya The domain Eukarya consists of organisms that have a nucleus. This domain is organized into four kingdoms:  Protista  Fungi  Plantae  Animalia Copyright Pearson Prentice Hall

32. Domain Eukarya Protista The kingdom Protista is composed of eukaryotic organisms that cannot be classified as animals, plants, or fungi. Its members display the greatest variety. They can be unicellular or multicellular; photosynthetic or heterotrophic; and can share characteristics with plants, fungi, or animals. Copyright Pearson Prentice Hall

33. Domain Eukarya Fungi Members of the kingdom Fungi are heterotrophs. Most fungi feed on dead or decaying organic matter by secreting digestive enzymes into it and absorbing small food molecules into their bodies. They can be either multicellular (mushrooms) or unicellular (yeasts). Copyright Pearson Prentice Hall

34. Domain Eukarya Plantae Members of the kingdom Plantae are multicellular, photosynthetic autotrophs. Plants are nonmotile—they cannot move from place to place. Plants have cell walls that contain cellulose. Copyright Pearson Prentice Hall

35. Domain Eukarya Animalia Members of the kingdom Animalia are multicellular and heterotrophic. The cells of animals do not have cell walls. There is great diversity within the animal kingdom, and many species exist in nearly every part of the planet. Copyright Pearson Prentice Hall