Classification and Taxonomy

1. Classification and Taxonomy Unit 5 Chapter 17

2. What is classification? • the grouping of objects or information based on similarities • This helps biologists understand how organisms are related to each other. • This is useful in agriculture, forestry, biochemistry, and medicine (to name a few fields).

3. Taxonomists study taxonomy • the branch of biology that groups and names organisms based on studies of their different characteristics Click on image to play video.

4. Aristotelian classification Life Plant Animal Herb Shrub Tree Aristotle grouped organisms based on appearance and abilities.

5. Carolus Linnaeus: 1707-1778 • Swedish botanist • Created modern classification system based on physical and structural similarities • Modern taxonomists have altered the Linnaean system to reflect evolutionary relationships.

6. Binomial Nomenclature • two-word naming system to identify organisms (Scientific Naming) • Genus: group of related species • always capitalized • Species: specific characteristics • always lower case • Ex: Homo sapiens When writing the scientific name which is Latin, one must italicize when typing or underline when handwriting. Genus species

7. Common names • Many people refer to organisms by common names rather than scientific names. • Be careful that common names do not always reflect the biology of the organism. • Scientific name: Fragaria ananassa • Common name: strawberry

8. Dichotomous key: system to identify organisms and their scientific names • A key is made up of sets of numbered statements. • Each set deals with a single characteristic of an organism, such as leaf shape or arrangement.

12. How living things are classified • Taxon: a group of organisms (taxa, pl.) • These groups (taxa) can be very broad or very specific. • The taxonomic levels from most broad to most specific: kingdom, phylum, class, order, family, genus, species

13. Taxonomic levels Domain Eukarya Kingdom Animalia Chordata Phylum Class Mammalia Carnivora Order Felidae Family Lynx Genus Species Lynx canadensis Lynx rufus Lynx Bobcat

14. Comparing related animals • Lynx rufus, lynx • Panthera concolor, mountain lion • Lynx canadensis, bobcat • Which two are more related? How do you know? Lynx Bobcat Mountain lion

15. What determines evolutionary relationship? • Anatomy and physiology • Common structures imply a common ancestor. • Breeding and behavior patterns • Geographic distribution • DNA and biochemistry DNA comparisons between these plants show almost no difference.

16. Phylogeny: Studying the evolutionary histories and relationships of organisms • Cladistics: a phylogenic study that assumes probabl groups of organisms diverged and evolved Allosaurus Velociraptor Archaeopteryx Sinornis Theropods Flight feathers; arms as long as legs Feathers with shaft, veins, and barbs 3-toed foot; wishbone Down feathers Light bones

17. Fan model to indicate phylogeny

18. Modern six-kingdom classification • Kingdom Archaebacteria: prokaryotic • Kingdom Eubacteria: prokaryotic • Kingdom Protista: eukaryotic • Kingdom Fungi: eukaryotic • Kingdom Plantae: eukaryotic • Kingdom Animalia: eukaryotic

19. Archaebacteria overview • Prokaryotic (no nucleus) • Most live in extreme environments such as swamps, deep-ocean hydrothermal vents, and seawater evaporating ponds. • Most do not use oxygen to respire.

20. Eubacteria overview • Prokaryotic • very strong cell walls • a less complex genetic makeup than found in archaebacteria or eukaryotes • diverse habitat

21. Kingdom Protista • Kingdom Protista contains diverse species that share some characteristics.

22. Protist overview • lacks complex organ systems • lives in moist environments • diverse metabolism

23. Fungi overview • Decomposes matter by absorbing materials • Multicellular or unicellular

24. Plant overview • Multicellular • Photosynthetic: produce oxygen • Immobile • Cell walls

25. Animal overview • Multicellular • Mostly mobile • Lack cell walls • Diverse habitats