Classification: Sorting it all out

1. Classification: Sorting it all out Pgs. 160 - 165

2. Classifying • Classification is the arrangement of organisms into orderly groups based on their similarities. • For thousands of years, humans have classified different kinds of organisms based on their usefulness. • The Chacabo people of Bolivia know of 360 species and have uses for 305 of them.

3. Why Classify? • Biologists classify organisms into living and extinct. • To understand the millions of different living things it makes sense to classify organisms. • Classifying helps us understand the relationships between different organisms and the traits they have. • To classify organisms, biologists use a system that groups them with similar characteristics. • Biologists use eight levels of classification: domain,kingdom, phylum, class, order, family, genus, and species.

4. Levels of clasification • Domains are the largest group of classification: Archaea, Bacteria, Eukarya • Kingdoms are the second level of classification and are broken down into phyla (phylum). • Phyla are sorted into classes which are sorted into orders. • Orders are sorted into families which are sorted into genera (genus) and then into species.

5. Classification levels for a cat • Domain: Eukarya (has cells with a nucleus) • Kingdom: Animalia (an animal) • Phylum: Chordata (contains a hollow nerve cord) • Class: Mammalia (has backbone and nurses its young) • Order : Carnivora (has teeth for tearing meat) • Family: Felidae (cats) • Genus : Felis (can not roar, but can pur) • Species: domesticus (domesticated)

6. What is the Basis for Classification? • Carolus Linnaeus was a Swedish physician and botanist who founded taxonomy. • Taxonomy is the science of identifying, classifying, and naming living things. • Linnaeus classified living things by shared characteristics. • Scientists later saw that an evolutionary link between animals formed a chain of common ancestors.

7. Modern CLassification • We still classify organisms based on presumed evolutionary relationships. • Species with a recent common ancestor can be classified together. • Bears, lions and cats look nothing alike but have a common mammal ancestor and can be classified together as Mammalia.

8. Branching Diagrams • Close evolutionary relationships between lions and house cats can be shown by a branching diagram. • The characteristics that make the animals different separates them, but the common characteristic keeps them linked.

10. Naming Names • Biologists are able to give organisms scientific names. • A scientific name is always the same for a specific organism no matter how many common names it might have. • Ancient biologists gave animals up to 12 names, but Linnaeus simplified the system with a two-part scientific name. • The first part is the genus and the second is the species. • Example: Indian Elephant (Elephasmaximus)

11. It’s All Greek/Latin to me • Scientific names may be difficult to understand because names are in Latin or Greek. • Tyrannosaurus rex is a combination of Greek and Latin words. • The first word means tyrant lizard, and rex means king. • The first word is always capitalized and the second is not. • A species cannot be named without both words.

12. Why are Scientific Names So Important? • A small black and white animal is pictured.. What is it? • The skunk is called by several different names in English and more in other languages. • For scientists of different countries to discuss the same animal, it is easier to have one official name for it: Mephitis mephitis

13. Dichotomous Keys • A dichotomous keys to aid in identifying unknown organisms. • It consists of several pairs of descriptive statements that have only two alternative responses. • From each pair of statements, a person can choose the appropriate statement to identify an organism.