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Classification:

Classification:. Georgia Performance Standards: SB3. Students will derive the relationship between single-celled and multi-celled organisms and the increasing complexity of systems.

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Classification:

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  1. Classification: Georgia Performance Standards: SB3. Students will derive the relationship between single-celled and multi-celled organisms and the increasing complexity of systems. b. Compare how structures and function vary between the six kingdoms (archaebacteria,eubacteria, protists, fungi, plants, and animals). c. Examine the evolutionary basis of modern classification systems. d. Compare and contrast viruses with living organisms. SB5. Students will evaluate the role of natural selection in the development of the theory of evolution. e. Recognize the role of evolution to biological resistance (pesticide and antibiotic resistance).

  2. Essential Questions: • How does the evidence of evolution contribute to modern classification systems? • Why classify? • On what criteria do Taxonomists base their classification of organisms? • Are viruses alive? • What is the role of evolution in antibiotic and pesticide resistance?

  3. Classification of Living Things

  4. Why Classify? • To study the diversity of life, biologists use a classification system to name organisms and group them in a logical manner. • In taxonomy, scientists classify organisms and assign each organism a universally accepted name.

  5. Why do scientists classify? • Biologists classify living organisms to answer questions such as: • How many known species are there? • What are the defining characteristics of each species? • What are the relationships between these species?

  6. Aristotle • Aristotle • Greek philosopher and teacher more than 2000 years ago • The first person to group or classify organisms (300 B.C.)

  7. Aristotle ANIMALS: PLANTS: Based on size of stem Based on where they lived

  8. Limitations of Early Classification 1. Not all organisms fit into Aristotle’s 2 groups (plants or animals) Ex: Bacteria Fungi Images from: http://www.leighday.co.uk/upload/public/docImages/6/Listeria%20bacteria.jpg http://danny.oz.au/travel/iceland/p/3571-fungi.jpg

  9. Limitations of Early Classification Ex: A jelly fish isn’t a fish, but a seahorse is! 2. Common names can be misleading Sea cucumber sounds like a plant but… it’s an animal! Image from: http://www.alaska.net/~scubaguy/images/seacucumber.jpg

  10. Limitations of Early Classification 3. Common names vary from place to place Ex: puma, catamount, mountain lion, cougar are all names for same animal Image from: http://www4.d25.k12.id.us/ihil/images/Cougar.jpg

  11. Limitations of Early Classification 4. Same organisms have different names in different countries. Chipmunk Streifenhornchen (German) Tamia (Italian) Ardilla listada (Spanish) Image from: http://www.entm.purdue.edu/wildlife/chipmunk_pictures.htm

  12. Limitations of Early Classification • Early Solution: • Description of Organism Using Latin Names RED OAK Quercus foliis obtuse-sinuatis setaceo-mucronatis “oak with leaves with deep blunt lobes bearing hairlike bristles”

  13. Limitations of Early Classification • Problem with Latin Name descriptions? • Names too long and difficult to remember • Names don’t illustrate evolutionary relationships

  14. Carolus Linneaus (1707-1778) Devised a new classification system based on morphology (Organism’s form and structure) “Father” of taxonomy and binomial nomenclature

  15. Carolus Linnaeus • Linnaeus’s Classification System • Organisms grouped in a hierarchy of seven different levels • Each organism has a two part scientific name • Binomial Nomenclature

  16. Early Efforts at Naming Organisms • The first attempts at standard scientific names often described the physical characteristics of a species in great detail. • Results in long names • Difficult to standardize the names of organisms • Different scientists described different characteristics.

  17. Binomial Nomenclature • Carolus Linnaeus developed a two-word naming system called binomial nomenclature. • In binomial nomenclature, each species is assigned a two-part scientific name. • First word is the genus • Second word is the species

  18. Binomial Nomenclature • Binomial Nomenclature: Two name naming system • Italicized or Underlined • 1st Name = Genus • Capitalized • 2nd Name = Species Identifier • Lower case

  19. Binomial Nomenclature Vampire batDesmodus rotundus Image from: http://212.84.179.117/i/Vampire%20Bat.jpg Eastern chipmunk Tamiasstriatus Image from: http://www.entm.purdue.edu/wildlife/chipmunk_pictures.htm

  20. Binomial Nomenclature Humans Homo sapiens Homosapiens Image from: http://www.earlylearning.ubc.ca/images/photo_baby.jpg

  21. A group or level of organization is called a taxonomic category, or taxon King Phillip Came Over From Genoa Spain The are 7 taxonomic categories. (from smallest to largest) species genus family order class Phylum kingdom. Linnaeus's System of Classification

  22. The 7 taxonomic categories • Species - a group of organisms that breed with one another and produce fertile offspring. • Genus - a group of closely related species. • Family- genera that share many characteristics. • Order - is a broad taxonomic category composed of similar families. • Class- is composed of similar orders. • Phylum- several different classes that share important characteristics. • Kingdom - largest taxonomic group, consisting of closely related phyla

  23. Kingdom • Phylum • Class • Order • Family • Genus • Species Kids Prefer Cheese Over Fried Green Spinach

  24. Kingdom • Phylum • Class • Order • Family • Genus Species Animalia Chordata Mammalia Carnivora Felidae Panthera leo http://www.vetmed.wisc.edu/dms/fapm/personnel/tom_b/2004-lion.jpg

  25. Classification Pop Quiz: 1. How are living things organized for study? 2. Describe the system for naming species that Linnaeus developed. 3. What are the seven taxonomic categories of Linnaeus’s classification system from largest to smallest? 4. Why do scientists avoid using common names when discussing organisms? 5. Based on their names, you know that the baboons Papioannubis and Papio cynocephalus do NOT belong to the same a. Class b. family c. Genus d. species

  26. Modern Taxonomy Organizes living things in the context of evolution

  27. Modern Evolutionary Classification  • Organisms are grouped into categories that represent lines of evolutionary descent, not just physical similarities • This strategy of grouping organisms together based on their evolutionary history is called evolutionary classification. • Modern classification systems are based upon biochemical and genetic evidence that indicates evolutionary relationships

  28. Modern Taxonomy: Evolutionary Relationships • Determined through the use of: • Morphology • Fossil Record • Embryology • Chromosomes • Macromolecules Evolutionary relationships can be illustrated on a phylogenetic tree

  29. 1. FOSSIL RECORD We can trace some changes over time through the fossil record. Evolutionary history = PHYLOGENY

  30. 2. MORPHOLOGY Shape and Function Image from: http://www.angelfire.com/ab7/evolution12/evolutionclues.html

  31. Morphology • Homologous Characteristics: • Same embryological origin (may have similar structure and function) • Example: Bat Wing and Human Arm Homologous characteristics suggest a recent common ancestor

  32. Morphology Bat wing and human arm develop from same embryonic structures HOMOLOGOUS STRUCTURES

  33. Morphology • Analogous Characteristics: • May have similar structure and function, but different embryological origin • Example: Bird Wing and Butterfly Wing Analogous characteristics evolved separately. Organisms not necessarily closely related.

  34. ANALOGOUSSTRUCTURES Bird wing and butterfly wing have evolved with similar function BUT different structure inside. http://uk.dk.com/static/cs/uk/11/clipart/bird/image_bird003.html Insects and birds NOT closely related! http://www.naturenorth.com/butterfly/images/05a%20tiger%20wing.jpg

  35. I don’t get it! • Analogous characters the same function but different underlying construction. • Homologous characters different functions, but show an anatomical similarity inherited from a common ancestor. **Important for cladograms!**

  36. 3. Embryology Animals whose embryos develop in a similar pattern may be related Image from: http://calspace.ucsd.edu/virtualmuseum/litu/03_3.shtml

  37. Even differences show relatedness amnion /am·ni·on/ (am´ne-on) bag of waters; the extraembryonic membrane of birds, reptiles, and mammals, which lines the chorion and contains the fetus and the amniotic fluid http://www.southtexascollege.edu/nilsson/4_gb_lecturenotes_f/4_gb_24_cla_ani_ve_spr2003.html

  38. 4. Chromosomes Similar karyotypes suggest closer relationships. Human: http://www.nationmaster.com/wikimir/images/upload.wikimedia.org/wikipedia/en/thumb/1/18/300px-Human_karyogram.png Chimpanzee: Middle School Life Science , published by Kendall/Hunt.

  39. Human- 46 chromosomes Chimpanzee- 48 chromosomes Even differences show relatedness Chimpanzees have 2 smaller chromosome pairs we don’t have Humans have 1 larger chromosome pair (#2) they don’t have. Human: http://www.nationmaster.com/wikimir/images/upload.wikimedia.org/wikipedia/en/thumb/1/18/300px-Human_karyogram.png Chimpanzee: Middle School Life Science , published by Kendall/Hunt.

  40. 5. Macromolecules • Comparison of macromolecules such as Proteins and DNA • Organisms with similar sequences are (thought to be) more closely related.

  41. Macromolecules

  42. Molecular Clocks Comparisons of DNA can also be used to mark the passage of evolutionary time. A model known as a molecular clock uses DNA comparisons to estimate the length of time that two species have been evolving independently. Comparison reveal how dissimilar the genes are. Degree of dissimilarity is an indication of how long ago the two species shared a common ancestor. Modern Evolutionary Classification

  43. Phylogenetic Classification • Phylogeny: the evolutionary history of a species. • Phylogenetic classification is a classification system that shows the evolutionary history of a species. • Cladistics: It is assumed that a group of organisms diverged and evolved from a common ancestral group. • Derived traits: Characteristics of the original group that are retained.

  44. Classification Using Cladograms • Cladistic analysis identifies and considers only the characteristics that arise as lineages evolve over time. • Characteristics that appear in recent parts of a lineage but not in its older members are called derived characters. • Derived characters can be used to construct a cladogram, a diagram that shows the evolutionary relationships among a group of organisms.

  45. Traditional Classification Versus Cladogram Section 18-2 Appendages Conical Shells Crustaceans Gastropod Crab Crab Limpet Limpet Barnacle Barnacle Molted exoskeleton Segmentation Tiny free-swimming larva TRADITIONAL CLASSIFICATION CLADOGRAM Go to Section:

  46. Cladistics • Shows evolutionary relationships based on “shared derived characteristics” • Cladistic relationships illustrated through the use of a Cladogram Phylogeny: Evolutionary History

  47. Cladogram: a branching diagram using cladistics. • Image taken from:http://evolution.berkeley.edu/evolibrary/article//evo_03

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