Classification of Life

1. Classification of Life

2. I. Grouping Organisms • taxonomy - the field of biology that identifies and classifies organisms • taxonomists analyze shared characteristics to determine evolutionary relationships

3. What do you call this organism?

4. I. Grouping Organisms • biological classification systems group the most closely related organisms together

5. Carl Linneaus • Classification used today - developed by Carl Linneaus (mid 1700’s) • Linneaus’ system originally included five levels of classification ; modern scientists have added two more

6. Classification System 1. Kingdom - (most general) 2. Phyla (singular: phylum) 3. Class 4. Order 5. Family 6. Genus 7. Species (most specific)

9. Species • Members of the same species can interbreed and produce fertile offspring

11. II. The Kingdoms • A. Archebacteria - extremists (prokaryotic) • B. Eubacteria - generalists (prokaryotic) • bacteria are difficult to classify, evolutionary relationships unclear, don’t fossilize well

12. C. Protista • unicellular/mulitcellular • eukaryotic • cells not specialized • autotrophs/ heterotrophs • ex. amoeba, algae, kelp

13. D. Fungi Yeast Mildew • eukaryotic • multicellular • have cell walls • heterotrophs - release digestive enzymes onto a food source and absorb nutrients • - ex. molds, mildews, yeast Club Fungi

14. E. Plantae • eukaryotic • multicellular • have cell walls • autotrophs (most)

15. F. Animalia • eukaryotic • no cell walls • heterotrophs • ex. sponges, insects, tigers

16. III. Naming Organisms • crawdad, crayfish, rock lobster all different names for the same species • clear communication among scientists around the world requires an international system for naming organisms

17. III. Naming Organisms • Binomial nomenclature: two names Bi= two, nomial= name Nomenclature= naming system • organisms scientific name consists of the genus name and the species name.

18. III. Naming Organisms • crayfish: Cambarus bartoni • genus name is capitalized, species name lower case • name should be italicized or underlined

19. Genus Ursus contains five other kinds of bears. • Ursusarctos • Ursusmaritimus • Ailuropodamelanoleuca

20. IV. Evolutionary Relationships • Phylogenetic treeshows the evolutionary relationships among organisms • more distant ancestors appear at the base • more recent relatives make up the branches

22. V. Ways to Classify • 1) Structure • 2) Fossil Record • 3) Biochemical Analysis (DNA sequencing, comparison of proteins) Despite the methods of classification, it it still often difficultto classify organisms

23. V. Ways to Classify • Taxonomy constantly changesas new information is discovered and theories are refined.

24. VI. Identifying Organisms • Dichotomous key is a tool used for identifying organisms (aka biological key) *A dichotomous key lists specific observable traits. • What does observable mean?

25. VI. Identifying Organisms • For each trait, the key consists of two contrasting options. • By picking the option that matches the organisms features, you can identify organisms • Dichotomous keys are often found in field guides

26. Dichotomous Key 1a …Has feathers go to 2 1b … no feathers go to 3 2a swims… duck 2b does not swim…hen 3a has legs … lizard 3b no legs … snake OR

27. VII. Uses of Classification • Taxonomists estimate that there are 1.5- 12 million different species on Earth today • The variety in living things is called biodiversity Bio = life, diversity = different kinds

28. VII. Uses of Classification • Thousands of researchers study many different species. Their work can reveal unknown facts about a species. • Example: A species of chameleon small enough to easily perch on a match head has been discovered on a tiny island off Madagascar. The discovery of Brookesiamicra, a species that grows to only just over a half-inch (16 millimeters) from nose to bottom.

29. VII. Uses of Classification • Also an unknown fungi was discovered. This fungi produces the drug cyclosporin which is used to prevent the rejection of transplanted organs