Evolution and Characteristics of Classification Systems

1. Classification Characteristics of and usefulness of classification systems

2. Evolution has created great diversity of life More than 2.5 million different kinds of organisms have been identified. It is estimated that as many as 20 million more may be discovered.

3. Features of a good classification system: 1. Needs to use universally accepted names for organisms 2. Doesn’t use common names--they can be misleading and confusing. • Mountain lion, cougar, puma, panther-same animal • Starfish, jellyfish, seahorse, groundhog

4. Organisms should be placed in groups that have meaning (share important traits) The science of naming is called taxonomy

5. Early Classification Systems: Aristotle-grouped animals by how they moved (fly, swim, walk). Even though it had obvious problems, his system was used for nearly 2000 years.

6. 18th century scientists began to use Latin but names were long (20 words or more), some organisms were given more than one name. • For example, the English translation of the scientific name of a tree might be “Oak with deeply divided leaves that have no hairs on their undersides and no teeth around their edges.”

7. Carl Linnaeus He was a Swedish Botanist; he developed the system for giving things two names. His method is called binomial nomenclature.

8. Each organism gets a first and last name. -the first name is the genus. It is a small group of very similar organisms. -the second name is the species. It is all the same organism Definition of a species: John Ray defined a species as organisms that can interbreed and have fertile offspring.

9. Examples: All dogs are the same species because they can interbreed and have fertile offspring. Horses and donkeys are not the same species because their offspring, a mule, is sterile.

10. Example: Acer rubrum-redmaple Acer palmatum-palmmaple

11. Example: Felis leo Felis tigris

12. How to write a scientific name: • The genus name is always capitalized, species is always small. It must then be underlined or italicized to be set apart. • Names are in Latin so the meanings won’t change with use.

13. Examples: Ursus arctos horribilus “horrible artic bear” for the grizzly bear

14. Ursus maritimus Polar bear Ursus americanus Black bear

15. Some are named for a location: • Microtus pennsylvanicus • Sphiggurus mexicanus

16. Some are named for people: Beyonce: Scaptia beyonceae

17. Barack Obama: Caloplaca obamae

18. 7 Categories: • Kingdom • Phylum • Class • Order • Family • Genus • Species

19. A way to remember: Kathy Kings Puts Play Cheese Chess On On Fresh Fine Garden Grain Salad Sand

20. Examples: • Human • animalia • chordata • mammalia • primate • homididae • Homo • sapien • Housecat • animalia • chordata • mammalia • carnivora • felididae • Felis • domesticus

21. Categories go from general to specific • Animal • Chordata • Mammalia • Carnivora • Ursidae • Ursus • artic horribilus

22. Modern Classification methods: Scientists often disagree on how to classify. The following are often looked at: 1. homologous structures 2. embryos 3. fossils 4. biochemicals a. DNA b. RNA c. proteins-Cytochrome c (found in all living things)

23. Kingdoms: • Linnaeus started with 2 kingdoms: plants and animals. • It became clear that not everything fit into those 2 kingdoms so more were added.

24. There are now 6 kingdoms: 1. Eubacteria--the most common bacteria. “eu” means “true”. All are prokaryotic.

25. 2. Archaebacteria--have different cell walls, lipids and ribosomes. All are prokaryotic.

26. 3. Protista—all are eukaryotic cells with a nucleus and other organelles. Some are plant-like and some are animal-like.

27. 4. Fungi--eukaryotic, plant-like but have different cell walls from plants, and they do not make their own food like plants.

28. 5. Plantae—all are multicellular, have cell walls made of cellulose, and are autotrophic

29. 6. Animalia—all are multicellular, have no cell walls, and are heterotrophic.