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Classification

Classification. Intro to Classification systems From two kingdoms to five (or six) Binomial nomenclature and dichotomous keys. Introduction to Classification. What is meant by classification? -To group living things based on similarities. Why classify living things? Scientific reasons….

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Classification

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  1. Classification • Intro to Classification systems • From two kingdoms to five (or six) • Binomial nomenclature and dichotomous keys

  2. Introduction to Classification • What is meant by classification? -To group living things based on similarities. • Why classify living things? • Scientific reasons…. • Medical reasons… • Taxonomy is the science of grouping and naming organisms.

  3. Questions • What was the major difference(s) between how both Aristotle and Linnaeus classified organisms? • What is binomial nomenclature and who devised this system? • Explain how this binomial system works.

  4. Questions Continued 4. Phylogeny is the study of the evolutionary history of organisms. Name the four lines of evidence used to create phylogenetic trees and give a brief description of what each refers to. 5. The modern system includes six classification levels. List the six levels.

  5. Aristotle’s system • ARISTOTLE - • *4th century BC (384 to322 BC)*Greek philosopher • 2000 years ago Aristotle divided living things into either plants or animals . • Animals were divided into groups based on where they lived; land, water, or air.They were also grouped based on whether they were blooded or bloodless. • The plants were divided into groups based on differences in their stems.

  6. Problems with his System • Using Aristotle's 3-group system (land, air water), name 2 animals that would fit each of the 3 groups. • Some possible Answers: a. walking - cat, dog, human, etc.b. flying - bird, bat, butterfly, etc.c. swimming - fish, whale, manatee, etc. • Do you see any possible conflicts here? • What about a duck or an alligator?

  7. Carolus Linnaeus 1707-1778 • He devised a system of grouping organisms into hierarchical categories based on physical characteristics, such as form or structure. • For example, Linnaeus's plant taxonomy was based solely on the number and arrangement of the reproductive organs on a plant. • Overall this proved to be a better system however it had some problems that resulted in many groupings that seemed unnatural.

  8. Binomial Nomenclature Linnaeus devised this system: The genus name is written first (always Capitalized). The species name is written second (never capitalized). Both words are either italicized or underlined. Eg.. Homosapiens or Homo sapiens

  9. Phylogeny The four lines of evidence used to create phylogenetic trees are: • The fossil record • Morphology • Embryological patterns of development • Chromosomes and DNA

  10. The Fossil Record: Anatomical similarities or patterns in relation to time on the evolutionary scale can be invaluable. • Similarly, relationships in the Morphology (morph refers to form) of the creatures we see today allow us to categorize organisms based on these facts.

  11. Embryological patterns of development • The changes that an organism undergoes during its development can leave clues to its evolutionary past.

  12. Chromosomes and DNA • The amount of genetic material that two organisms share relates to how close they are on the phlogenetic tree • Surely you have heard how humans and chimpanzees share 98% of the same DNA.

  13. The major classification levels,from largest group to smallest (several of these have subdivisions) • KingdomPhylumClassOrderFamilyGenusSpecies

  14. Scientific classification Kingdom: Animalia Phylum: Chordata Class: Actinopterygii Order: Gadiformes Family: Gadidae Genus: Gadus Species: Gadus morhua

  15. Idenitifying Marine Organisms • Some things we know by sight: fish, crab • These words are different in other languages: poisson, fisch, pescado, pesce. • Scientists all over the world know that Gadus morhua is Atlantic cod. • There are many types of cod in the Genus Morhua but only one species: • Gadus morhua

  16. Species • A group of organisms that look alike and can interbreed under natural conditions to produce fertile offspring. • When similar species are in close contact, interbreeding can take place for example, dolphin and whale to produce a wolphin. These animals are infertile and can’t have offspring so they are not new species.

  17. Bottlenose Dolphin + False Killer Whale = Wholphin or wolphinTursiops truncatus (mother) + Pseudorca cracrassidens

  18. Classification of Living Things • http://www.eti.uva.nl/Database/WBD.html • http://www.usoe.k12.ut.us/curr/science/sciber00/7th/classify/sciber/history.htm • http://www.ucmp.berkeley.edu/exhibit/phylogeny.html http://www.howe.k12.ok.us/~jimaskew/bclasfy.htm

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