Classification

1. Classification

2. Why do we classify things? Finding Order in Diversity • Classification provides scientists and students a way to sort and group organisms for easier study. • Taxonomy – branch of biology that deals with the classification and naming of living things • There are millions of organisms on the earth! (approximately 1.5 million have been already named) Classification

3. Classifying and Naming Organisms Grouping organisms based on comparing characteristics makes it easer to study the diversity of live. Binomial Nomenclature – 2 word system of identifying each kind of organism; avoids confusion A. Carolus Linnaeus – founder of modern taxonomy; used structural similarities as a basis for his classification system Classification

4. Classification Carolus Linnaeus Why do biologists consider Linnaeus’s system an improvement over earlier systems?

5. Classification

6. Classification

7. Classifying and Naming Organisms Binomial Nomenclature (cont.) B. Scientific Name – both names together i. 1st name – genus (always capitalized) ii. 2nd name – identifies species within the genus (lower case) iii. Name is written in italics or underlined Classification

8. Linnaeus’s Classification System – hierarchical system from most inclusive to least inclusive are: Classification

9. This illustration shows how a grizzly bear, Ursusarctos, is grouped within each taxonomic category. Classification

10. Go to Fig. 18-4 What do the scientific names of the polar and grizzly bears tell you about their similarity to each other? Classification

11. Linnaeus’s system was limited because similarities and differences were mainly visible What was invented that helped to change the way scientists classify organisms? Modern Evolutionary Classification

12. Evolutionary classification based on Darwin’s Theory of Evolution – Decent with Modification Species gradually change, or evolve, over time from pre-existing species Modern Evolutionary Classification

13. Classifying species based on easily observed adult traits can pose problems. Which of these organisms seem most alike? Modern Evolutionary Classification

14. Cladograms – a diagram that shows evolutionary relationships among organisms based on shared derived characters (Fig. 18-7) Modern Evolutionary Classification

15. Structural – ex. Skeletal structure, leaf anatomy Ways is which taxonomists classify

16. Structural – ex. Skeletal structure, leaf anatomy Ways is which taxonomists classify

17. Behavioral – similar behaviors may indicate a close relationship – Fig. 18-8 American and African vultures look very much alike and were once classified together. American vultures have a peculiar behavior: When they get overheated, they urinate on their legs to cool down. The stork is the only other bird known to behave this way. Ways is which taxonomists classify

18. Biochemical – information about DNA, RNA & proteins can be used to help determine relationships and can be used to estimate how long different species have been separated Ways is which taxonomists classify African Vulture American Vulture Wood Stork

19. Cytological – cellular structure – ex. Prokaryotic vs. eukaryotic, plant cell vs. animal cell Ways is which taxonomists classify

20. Embryological – early stages of development may show shared characteristics that are absent at the adult stages (Fig. 15-17 pg. 385) Ways is which taxonomists classify

21. Fossil Formation – establish relationships between modern-day species & those that lived years ago Ways is which taxonomists classify