Classification of Organisms

1. Classification of Organisms HW:

2. Taxonomy • The assignment of a distinctive name to each of the groups in a classification system.

3. Animal Systematics • What is systematics? • The study of the kinds and diversity of organisms and the evolutionary relationships among them.

4. Three schools of Systematics • 1. Evolutionary Systematics: Grouping based on evolutionary relationships. Homologous and analogous relationships are both important. • 2. Cladistics: Grouping also based on evolutionary relationships. Only homologous relationships are important. • 3. Numerical Systematics: Grouping based on math models and the number/proportion of characteristics per animal.

5. Classification System (Modern) • Seven levels of classification (taxa) (Domain) • 1.Kingdom • 2.Phylum • 3.Class • 4.Order • 5.Family • 6.Genus • 7.Species

6. Classification System (Modern) • Taxa begin with the largest, broadest groups to the smaller, more specific groups.

7. 5 Kingdoms (recently updated to 6) 1. Monera (a. Eubacteria; b.Archaebacteria)  2.Protista  3.Fungi  4.Plantae  5.Animalia

8. Binomial Nomenclature – Universal Naming system • A scientific name of an organism contains two parts. The first name is the genus name and the second name is the species name. • Here are some simple rules in writing a scientific name: • 1.The first letter of the Genus name must be capitalized. • 2.The first letter of the species name is not capitalized. • 3.Both names must be underlined or italicized.

9. Evolutionary Relationships • Homologous features: characteristics/structures that have a similar origin but different function. • Ex.

10. Evolutionary Relationships • Analogous features: characteristics/structures that have different origins but the same function. • Ex.

11. Common Classification Terms • Key: a structural map of taxa. Used to place an animal into the correct group by successfully eliminating choices.

12. Common Classification Terms • Symmetry: the layout of an animal’s body • 1.Asymmetrical: no noticeable pattern or shape, irregular • 2.Radially symmetrical: circular or tubular pattern. Cut halves look similar. 3. Bilaterally symmetrical: Left side a mirror image of the right side down a longitudinal plane.

13. Common Classification Terms • Body Cavities CP 66 • 1.Acoelomate – no body cavity • 2.Pseudocoelomate – (false body cavity) an unlined body cavity 3. True coelomate - a body cavity lined with peritoneum.

14. Common Classification Terms • Digestive systems • 1.Two-way digestive system: only has one opening (mouth) for food to enter and wastes to exit. • 2.One-way digestive system: have two openings (mouth, anus) for food to enter and wastes to exit.

15. Common Classification Terms • Circulatory systems • 1.Open system: has blood vessels that are not interconnected. Blood empties into cavities or sinuses. • 2.Closed system: has blood vessels that are interconnected in which blood continuously flows.

16. Common Classification Terms • Skeleton • 1. Hydrostatic pressure – body fluids support body • 2.Exoskeleton – skeleton covering body tissue. • 3.Endoskeleton – body tissue covers the skeleton.

17. Common Classification Terms • Movement • 1.Sessile: attached to one place; rarely move • 2.Free floating: able to move but lack control of direction • 3.Mobile: able to control movements.