Classification of Living Things

1. Classification of Living Things Chapter 18

2. Why Classify • Classification is used to name organisms and group them in a logical manner • Biologists have classified and named over 1.5 million species • Estimate that 2 million- 100 million have yet to be discovered

3. Taxonomy • A branch of biology where scientists classify organisms and assign each a universally accepted name

4. Taxonomy • A good classification system puts organisms in groups with other organisms that are similar • Originally based on physical characteristics • Physical traits are shared amongst unrelated organisms • Convergent evolution • Shark vs. dolphin • Bird vs. bat

5. Common Names • Organism were originally referred to by common names • Names that are unique to a small group of people • With out discussion; draw what comes to mind when you hear the word: cat

6. Use of common names • Common names can be misleading • Given based on physical characteristics and what the organism reminds usof jellyFISH Sea CUCUMBER seaHORSE

7. Use of common names • Common names vary among languages and even regions in the same country • Mountain lion • Puma • Cougar • Panther

8. Use of common names • Different species sometimes share a common name • What is a buzzard??? United Kingdom (England)- Hawk United States- Vulture

9. Removing Confusion • First Naming system • scientists used detailed physical descriptions • Names were long and hard to remember • Carolus Linnaeus (mid 18th century) • Developed a two word naming system called Binomial nomenclature • shows ancestral relation

10. Binomial Nomenclature • scientific names are used to avoid confusion • Universally accepted Cathartes aura Buteojamaicensis

11. Taxonomic Nomenclature • Hierarchical system (consists of levels) • Each level is a taxon Kingdom Phylum Class Order Family Genus Species Kids Prefer Candy Over Fried Green Spinach

12. Kingdom- Animalia Phylum- Chordata Class- Mammalia Order- Carnivora Family- Felidae Genus- Panthera Species- leo

13. Binomial Nomenclature Rules to follow • Always written in italics (or underlined) • First word is capitalized (genus name) • Second word is lowercased (species name)

14. Binomial Nomenclature • Genus a group of closely related species Ursus

15. Binomial Nomenclature • Species a group of similar organisms that can breed and produce fertile offspring UrsusUrsusUrsus arctosmaritimusamericanis

17. Modern Evolutionary Classification 18.2

18. Modern Evolutionary classification • Taxonomic groups are invented by scientist to group organisms with similar characteristics

19. Which Similarities are most important • Taxonomists try to group organisms according to biologically important characteristics • Linnaeus grouped species based on visible similarities (Dolphin example: Fish vs. Mammal) Barnacle crab limpet

20. Evolutionary Classification Limpet and barnacle larvae are very different. • Barnacles have jointed limbs, Limpets DON’T ! • Barnacles have a segmented body, Limpets DON’T ! • Barnacles have an exoskeleton that molts, Limpets DON’T !

21. Evolutionary Classification Crab and barnacle larvae are very similar • Barnacles have jointed limbs, So do CRABS ! • Barnacles have a segmented body, So do CRABS ! • Barnacles have an exoskeleton that molts, So do CRABS !

22. Evolutionary Classification • Organisms are grouped together based on evolutionary decent not just physical traits (WHY??) • The higher the level of the taxon, the further back in time is the common ancestor

23. Lion • Kingdom: Animalia • Phylum: Chordata • Class: Mammalia • Order: Carnivora • Family: Felidae • Genus: Panthera • Species: leo Tiger • Kingdom: Animalia • Phylum: Chordata • Class: Mammalia • Order: Carnivora • Family: Felidae • Genus: Panthera • Species: tigris

24. Lion • Kingdom: Animalia • Phylum: Chordata • Class: Mammalia • Order: Carnivora • Family: Felidae • Genus: Panthera • Species: leo Grey Wolf • Kingdom: Animalia • Phylum: Chordata • Class: Mammalia • Order: Carnivora • Family: Canidae • Genus: Canis • Species: C. lupus

25. Cladistic analysis • Cladogram: a diagram used to show evolutionary relationships • A way of classifying organisms using only new evolutionary characteristics • Derived characteristics- These characteristics appear in later organisms but not earlier ones

26. Molecular Clock • Used to compare DNA of organisms • The more similar the DNA the more recently the organisms branched off from one another • Neutral Mutations- are not affected by natural selection • Accumulate in the DNA over time (at the same rate in all species)

27. Cladogram • Help us to understand how one lineage branched from another in the course of evolution. (family tree)

28. 1. ______ Wings2. ______ 6 Legs3. ______ Segmented Body4. ______ Double set of wings 5. ______ Jumping Legs6. ______ Crushing mouthparts7. ______ Legs8. ______ Curly Antennae

29. Answer 1. ___F___ Wings2. ___C___ 6 Legs3. ___A___ Segmented Body4. ___G___ Double set of wings5. ___E___ Jumping Legs6. ___D___ Crushing mouthparts7. ___B___ Legs8. ___H___ Curly Antennae

30. Kingdoms and Domains The tree of Live “Evolves”

31. Changes in the classification system • New biological understanding lead to a more accurate classification system • Genes show important similarities at the molecular level • Linnaeu’s didn’t know about DNA • DNA from organisms can be sequenced and compared to show evolutionary relationships.

32. Molecular Clocks • DNA comparisons can be used to estimate how long 2 species have been evolving independently. • Mutations in the genes accumulate at different rates • The more similar mutations 2 species have the closer related they are

33. Effect on Classification • Scientist used to believe there were just 2 groups of living things: plants and animals • 2 kingdom system doesn’t adequately represent diversity of life • 6 kingdom system: • Eubacteria • Archaebacteria • Protista • Fungi • Plantae • Animalia

34. Eubacteria • Prokaryote • Unicellular • Autotroph or Heterotroph • Cell wall with peptidoglycan (extra outer layer) • Ecologically diverse (Common Bacteria) • Free-living soil organisms • Parasites • Photosynthetic • Anaerobic • aerobic

35. Archaebacteria • Prokaryote • Unicellular • Autotroph or Heterotroph • Cell wall without peptidoglycan layer • Live in the most extreme environments (first living organisms) • Volcanic hot springs • Brine pools • Black organic mud (NO oxygen)

36. Protista • Eukaryote • Most are unicellular • Autotroph or Heterotroph • Cell walls of cellulose • Some have chloroplasts • Made up of organisms that cannot be classified elsewhere

37. Fungi • Eukaryote • Most are Multicellular (some unicellular) • Heterotrophs • Feed on dead or decaying matter • Secrete digestive enzymes to break down food • Cell wall of chitin

38. Plantae • Eukaryote • Multicellular • Autotroph • Carry out photosynthesis • Chloroplasts • Cell wall of cellulose • Non-motile (cannot move from place to place)

39. Animalia • Eukaryote • Multicellular • Heterotroph • No cell wall • Most can move (at least at some point in there life cycle) • Very diverse group • Species that exist in almost every part of the planet

40. 3 Domain System • Molecular clock analysis allows scientists to group organisms according to how long they have been evolving independently • The domain is a more inclusive category than any other • 3 Domains: Bacteria, Archaea, and Eukarya

41. Domain/ Kingdom Relationship