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Classification of Life

Classification of Life. How do we classify organisms into groups? making categories based upon similarities and differences Why ? Natural human desire for order.

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Classification of Life

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  1. Classification of Life How do we classify organisms into groups? making categories based upon similarities and differences Why? Natural human desire for order

  2. Classification goes back to the beginning of time. Dinosaurs classified things. Really, they did! For example, plant-eaters classified things as “What can I eat?” and “What will eat me?” They classified their food – “What can I eat?” and “What can’t I eat?” Early man also classified things much the same way. It didn’t take many members of your hunting party being eaten by a saber tooth tiger to know you wanted to stay away from the saber tooth and its cousins

  3. Taxonomy names and groups organisms according to their characteristics and evolutionary history Is the science of describing, naming and classifying organisms

  4. History of Classification Over 1,750,000 species have been given names. There are 10 million yet to be discovered 99% of all plant and animal species that have ever existed are now extinct, most left no fossil record.

  5. Early System of Classification Aristotle— He divided things into animals, vegetable and minerals. Focusing of the two taxa Plants and animals Animals—classified as: -Land dweller -Water dwellers -Air dwellers Plants—Three categories based on stems: herbs, shrubs and trees

  6. Problems with Early Systems Common names - there are local differences and they can be unclear. Names were polynomial - names used descriptive terms, so some were thirteen or more words long. The term for a honey bee: -Apispubescences, thorace, subgriseo, abdomine fusco, pedibusposticisglabrisuntrinquemargine ciliatis.

  7. Classifying organisms Naturalists replaced Aristotle's classification system because it did not adequately cover all organisms and because his use of common names was problematic Naturalists have invented several systems for categorizing Biodiversity, which is the variety of organisms considered at all levels from populations to ecosystems. .

  8. Carolus LinnaeusThe Linnaean System Hierarchical categories - using morphology. Binomial system - two names There are seven levels of classification:

  9. Levels of Classification 1. Kingdom-largest (six kingdoms)-least specific 2. Phylum 3. Class 4. Order 5. Family 6. Genus 7. Species-smallest-(most specific)

  10. Mnemonic Device: K ___King P ___Phillip C ___Came O ___Over F ___ For G ___Good S ___Soup

  11. How can you remember each level of the classification hierarchy? Katy please come over for ginger snaps. Kids prefer cheese over fried green spinach. King Phillip called out for good soup. King Philip can only farm green spinach. Kenneth, please close our front gate soon. Keep plates clean or family gets sick

  12. There are five Kingdoms • Kingdom Monera Over 10,000 species Members – Bacteria and Cyanobacteria (blue-green algae) • Kingdom Protista Members – Protozoans and unicellular/ multi-cellular algae Kingdom Fungi Over 100,000 species Members – Include mushrooms and mold • Kingdom Plantae Over 250,000 species Members – Make own food through photosynthesis • Kingdom Animalia Members – All members of Animalia are multicellular, and all are heterotrophs (that is, they rely directly or indirectly on other organisms for their nourishment). Most ingest food and digest it in an internal cavity.

  13. Phylum (Division for Plants) – Groups of classes with shared characteristics; members of a phylum share a common structure and organization; Chordate Phylum (animals with backbones). Class – Members share common structure; made up of several Orders; Class Mammalia (have mammary glands).

  14. Order – Share common structure and traits; made up of several Families; Order Primate (flexible hands and feet). Family – Share common characteristics; made up of several Genera; Family Homindae (bipedal – walks on two feet).

  15. Genus – Have common characteristics, structures, and organization; made up of several Species; Genus Homo (large brain). Species – Most basic; members resemble each other; can produce fertile offspring; sapiens (knowing, knowledge, thinking). The scientific name for human beings is Homo sapiens. Homo – Latin for “man.” sapiens – Latin for “wise; to be wise.” Homo sapiens – The Wise Man.

  16. Linnaeus gave species two names. The two names are the genus and species. This is known as binomial nomenclature or the scientific name. All names are given in Latin. This is because Latin does not change. It is a dead language so it does not change to meet a society’s needs All Names are unique for each species. By using a scientific name, you know exactly which species you are talking about.

  17. The scientific name also tells you which species are similar. Which of these three species are similar: Erithacusjohnstoniae Turdusmigratorius Erithacusrubecula

  18. If you selected Erithacus johnstoniae and Erithacus rubecula, you are correct! Erithacus johnstoniae and Erithacus rubecula share the same genus – Erithacus. While different species, these two birds still share some common characteristics

  19. How do we go about classifying things? Living things are classified based on “observable properties!” (“Observable properties” are things you can see) Examples of observable properties: Living, once living, non-living External structure – hard or soft Patterns – geometric shapes, symmetry, etc.

  20. Rules you need to follow when classifying Know what is being classified. Make many observations about the things being classified. Classify things based on your observations. Group the most similar things together. When grouping living things, place the most similar organisms in the same species. The largest, or most general, group of living things is the kingdom.

  21. How do we classify? • Structural (anatomy and physiology) • Biochemical (enzymes, proteins, DNA) • Cytological (cell structure) • Embryological (development) • Behavioral (patterns of actions) • Fossil (common ancestor)

  22. Major Taxonomic Groups • Six Kingdoms • Archebacteria – oldest life form • Eubacteria - most living bacteria • Fungi – molds, yeasts, mushrooms • Plantae - plants • Animalia - animals • Protista – single celled organisms (eukaryotic) S4

  23. Dichotomous Key • Tool used by biologists to identify an unknown organism • Series of paired statements of anatomical description that leads to an identification. S5

  24. Next …. How to understand what others have classified • Is this all there is to classification? Of course not! Now you know how to classify, you want to go out and use that information to identify things. • Have you ever seen a bird and wondered what type of bird it was? Classification gives you an important tool to use. This tool is called a classification key (also called a dichotomous key).

  25. The classification key is a set of “yes-or-no” questions that help you identify what you are looking at. Let’s look at an example: • You have money in a pile. You have some brown and silver coins as well as some paper money. You want to identify what you have. The classification key you might use may look something like this: • 1 A. Is it made of metal? Go to 2 • 1 B. Is it made of paper? Go to 5

  26. What bird am I ?

  27. Bird W is Geospiza • Bird X is Platyspiza • Bird Y is Certhidea • Bird Z is Camarhynchus

  28. Key for Vertebrate Identification • 1. a) animal has a spine…………………..go to 2 b) animal has no spine………..…invertebrate 2. a) animal has no gills and fins……..…. go to 3 b) animal has gills and fins…………….. Fish 3. a) animal has no scales…………..........go to 4 b) animal has scales………………..….reptile 4. a) animal has feathers …………………..bird b) animal has no feathers ……………..go to 5 5. a) animal has hair…………………….mammal b) animal has no hair………………..amphibian What am I ???

  29. Modern System of Classification Six kingdom system • Archaebacteria: unicellular prokaryotes, • harsh environments. • Eubacteria: common form of bacteria, • circular chromosomes, most are aerobic. • Protista: eukaryotesm mostly unicelluar, no • complex tissues or systems.

  30. Fungi: heterotrophic eukaryotes, unicellular and multicellular, absorb nutrients, 100,000 species. • Plantae: Eukaryotes, multicellular, most are autotrophic—photosynthesis, 350,000 species. • Animalia: Eukaryotes, multicellular, heterotrophic, most have symmetrical bodies

  31. Three Domain System based on rRNA • Domain Archaea– archaebacteria • Domain Bacteria—eubacteria • Domain Eukarya—protists, fungi, plants and animals

  32. What we will do • These notes are your study guide for the quiz on 3/24. • Will practice grouping objects and animals • Will learn to write a dichotomous key • Will use a dichotomous key to identify organisms

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