Taxonomy

1. Taxonomy The science of classifying living organisms

2. History • During the 1700’s naturalists were bringing many examples of new species back to Britain • Scientists needed a way to keep all the organisms straight • Carolus Linnaeus came up with a classification system that we use today

3. History continued… • Linnaeus’ system originally had two kingdoms: • Plantae and Animalia • New kingdoms have been added as we learn new information • Now there are 6 kingdoms

4. The Seven Levels • Organisms are sorted into seven levels of classification: • Kingdom (the broadest, many type of organisms) • Phylum • Class • Order • Family • Genus • Species (the narrowest, one type of organism) King Philip came over for great spaghetti

5. The Seven Levels • Organisms are first put into kingdoms based on their similar characteristics • They are then further sorted through the seven levels • As you move DOWN the levels, the organisms in each level share more and more characteristics • The more levels two organisms share in common, the MORE related they are

6. The Seven Levels for a Mountain Lion

7. How do scientists classify organisms? • Scientists put organisms into groups based on SIMILAR CHARACTERISTICS • Always look for what characteristics organisms have in common • Scientists first began using physical evidence to classify organisms. • Now they also use fossil and DNA evidence

8. Classifying Organisms • Physical Evidence • Scientists examine: • Skeletal Structure • Homogolous structures: Bones that are similar • Common behaviors • Similar appearance • Habitats • And more…

9. Classifying Organisms • Fossil Evidence • Scientists examine fossils to determine what organisms have common ancestors • Organisms with a recent common ancestor are more closely related than those with a very old common ancestor

10. Classifying Organisms • Genetic Evidence • Scientists have more recently started examining similarities in DNA and proteins • The more similar the DNA sequence, the more closely related are two organisms • Upon using genetic evidence, scientists found some previous classifications were incorrect

11. Classifying Organisms • DNA is the best evidence when classifying organisms • As scientists learn more about an organism, it’s classification may change

12. Scientific Names • Carolus Linnaeus came up with a system for assigning two name scientific names to an organism • His system is known as binomial nomenclature • Each organisms scientific name consists of it’s Genus name followed by it’s Species name

13. Scientific Names • When looking to identify commonly related organisms, use their first name • For example: Felis concolor (Pumas) are more closely related to Felis domesticous (house cats) than they are to Pinus concolor (white pine trees)

14. Scientific Names • Scientific names are used so that scientists from different countries can communicate easily about various types of organisms • Some organisms have more than one common name (ex. Mountain lion, puma, cougar) or different common names in different languages

15. Identifying Organisms • Scientists often need to identify organisms, so they know if it is a previously identified species • They use tools called a Dichotomous Key • Dichotomous Keys compare two traits in a step-by-step fashion to help one identify an organism

16. A Dichotomous Key 1. Has green colored body ......go to 2 Has purple colored body ..... go to 4 2. Has 4 legs .....go to 3 Has 8 legs .......... Deerus octagis 3. Has a tail ........ Deerus pestis Does not have a tail ..... Deerus magnus 4. Has a pointy hump ...... Deerus humpis Does not have a pointy hump.....go to 5 5. Has ears .........Deerus purplinis Does not have ears ...…go to 6 Identify Organism D