Unit 17a Scientific classification

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Unit 17a Scientific classification

  1. 1. KEY CONCEPT Organisms can be classified based on physical similarities.<br />
  2. 2. Linnaeus developed the scientific naming system still used today.<br />Taxonomy is the science of naming and classifying organisms. <br />White oak:Quercus alba<br /><ul><li>A taxon is a group of organisms in a classification system.</li></li></ul><li>Binomial nomenclature is a two-part scientific naming system.<br /><ul><li>uses Latin words. Why?
  3. 3. scientific names always written in italics. Why?
  4. 4. two parts are the genus name and species descriptor. Why?</li></li></ul><li><ul><li>A genus includes one or more physically similar species.
  5. 5. Species in the same genus are thought to be closely related.
  6. 6. Genus name is always capitalized.
  7. 7. A species descriptor is the second part of a scientific name.
  8. 8. always lowercase
  9. 9. always follows genusname; never written alone</li></ul>Tyto alba<br />
  10. 10. <ul><li>Scientific names help scientists to communicate. How?
  11. 11. Some species have very similar common names.
  12. 12. Some species have many common names.</li></li></ul><li>Linnaeus’ classification system has seven levels.<br />Each level is included in the level above it.<br /><ul><li>Levels get increasingly specific from kingdom to species.</li></li></ul><li>Ah yes, it’s time for another mnemonic device!<br />How will you remember the order of classification groups? K-P-C-O-F-G-S<br />Kingdom<br />Phylum<br />Class<br />Order<br />Family<br />Genus<br />Species<br />
  13. 13. The Linnaean classification system has limitations.<br />Linnaeus taxonomy doesn’t account for molecular evidence. Why?<br />The technology didn’t exist during Linneaus’ time.<br />Linnaean system based only on physical similarities.<br />
  14. 14. <ul><li>Physical similarities are not always the result of close relationships.
  15. 15. Genetic similarities more accurately show evolutionary relationships.</li></li></ul><li>KEY CONCEPT Modern classification is based on evolutionary relationships.<br />
  16. 16. Cladistics is classification based on common ancestry.<br />Phylogeny shows the evolutionary history for a group of species.<br />evidence from living species, fossil record, and molecular data<br />shown with branching tree diagrams using a method called Cladistics.<br />
  17. 17. Cladistics is a common method to make evolutionary trees.<br /><ul><li>species placed in order that they descended from common ancestor</li></li></ul><li><ul><li>A cladogram is an evolutionary tree made using cladistics.
  18. 18. A clade is a group of species that shares a common ancestor.
  19. 19. Each species in a clade shares some traits with the ancestor.
  20. 20. Each species in a clade has traits that have changed.</li></li></ul><li>Tetrapoda clade<br />1<br />Amniota clade<br />2<br />Reptilia clade<br />3<br />Diapsida clade<br />4<br />Archosauria clade<br />5<br />FEATHERS & TOOTHLESS BEAKS.<br />SKULL OPENINGS IN FRONT OF THE EYE & IN THE JAW<br />OPENING IN THE SIDE OF THE SKULL<br />SKULL OPENINGS BEHIND THE EYE<br />EMBRYO PROTECTED BY AMNIOTIC FLUID<br />FOUR LIMBS WITH DIGITS<br />DERIVED CHARACTER<br /><ul><li>Derived characters are traits shared in different degrees by clade members.
  21. 21. more closely related species share more derived characters
  22. 22. Derived characters are represented on cladograms as hash marks
  23. 23. Oldest relatives are at the bottom of the cladogram.</li></li></ul><li>CLADE<br />Tetrapoda clade<br />1<br />Amniota clade<br />2<br />Reptilia clade<br />3<br />Diapsida clade<br />4<br />Archosauria clade<br />5<br />NODE<br />FOUR LIMBS WITH DIGITS<br />DERIVED CHARACTER<br /><ul><li>Nodes represent the most recent common ancestor of a clade.
  24. 24. Clades can be identified by snipping a branch under a node. In this example, the different clades are distinguished by different colors.</li></ul>FEATHERS AND TOOTHLESS BEAKS.<br />SKULL OPENINGS IN FRONT OF THE EYE AND IN THE JAW<br />OPENING IN THE SIDE OF THE SKULL<br />SKULL OPENINGS BEHIND THE EYE<br />EMBRYO PROTECTED BY AMNIOTIC FLUID<br />
  25. 25. Molecular evidence reveals species’ relatedness. What would you expect to see when comparing the DNA of two closely related species? <br />Molecular data may confirm classification based on physical similarities.<br />Molecular data may lead scientists to propose a new classification. <br /><ul><li>DNA is usually given the last word by scientists. </li></li></ul><li>If two organisms are in the same phylum, what other taxon do they have in common? <br />A. class <br />B. kingdom <br />C. family <br />D. genus <br />
  26. 26. If two organisms are in the same phylum, what other taxon do they have in common? <br />A. class <br />B. kingdom <br />C. family <br />D. genus <br />Correct Answer = B<br />What is a species? <br />A. a group of organisms that live in the same habitat <br />B. a group of organisms that have similar structures <br />C. a group of organisms that compete for the same food source <br />D. a group of organisms that can breed and produce offspring that can reproduce <br />
  27. 27. If two organisms are in the same phylum, what other taxon do they have in common? <br />A. class <br />B. kingdom <br />C. family <br />D. genus <br />Correct Answer = B<br />What is a species? <br />A. a group of organisms that live in the same habitat <br />B. a group of organisms that have similar structures <br />C. a group of organisms that compete for the same food source <br />D. a group of organisms that can breed and produce offspring that can reproduce <br />Correct Answer = D<br />
  28. 28. Review<br />Taxonomy is the science of naming and classifying organisms<br />Binomial nomenclature is a two-part scientific naming system<br />The classification groups from largest to smallest = kingdom, phylum, class, order, family, genus, species<br />Cladistics is classification based on common ancestry<br />Molecular evidence reveals species’ relatedness<br />DNA is usually given the last word by scientists<br />

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