CLASSIFYING ORGANISMS

1. CLASSIFYING ORGANISMS The science of taxonomy Chapter 6, page 90

2. TAXA • Greek word that means categories or groups . • The singular form of the term is taxon . • Taxonomy is the science that deals with the classification or grouping of living things.

3. Sorting is a natural process.

4. Schools are examples of taxa...

5. The purpose of classification systems: • A classification system brings order to the many parts of a band and it organizes the students and staff in a school. • A classification system for organisms brings order to a wide range of different plants and animals.

6. The first classification system • Greek philosopher, Aristotle, is credited with developing a system for sorting plants and animals in 400 BC. • His system consisted of two kingdoms; the plant and animal kingdoms. • Plants were grouped according to their stemstructure and size. The 3 subgroups were herbs, shrubs and trees. • Animals were placed in 3 subgroups according to their habitat; water,air,and land.

7. tulip fish robin maple snake grass rose bush dolphin Frog duck seals beaver bacteria amoeba mosquito larva virus Using Aristotle’s system where would you place the following organisms?

8. Gradually Aristotle’s system showed weaknesses. Can you identify any? • It was not specific enough. Where an animal lived was too general. • More organisms were being discovered that would not fit into these simple groups. • The microscope discovered many organisms that would not fit into Aristotle’s classification system. • NOTE: despite its weaknesses this first classification system was used for about 2,000 years. • Who improved on this old system?

9. Modern Taxonomy • 1600’s • John Ray: he introduced a term called species. • John Ray stated that a species was a group of organisms that 1. Were similar in structure and 2. Were able to mate and pass the traits to their offspring.

10. Founder of modern taxonomy • Carolus Linnaeus (also in the 1600’s) • Linnaeus also used structural similarities as the basis for his taxanomic system. • Linnaeus introduced the idea of starting with a large group or kingdom and subdividing the kingdom into subgroups. • This allowed for more organisms to be sorted more precisely.

11. 7 Taxa / Groups 1. KINGDOM 2. PHYLUM 3. CLASS 4. ORDER 5. FAMILY 6. GENUS 7. species Example: human 1. Animalia 2. Chordata 3. Mammalia 4. Primates 5. Hominidae 6 Homo 7 sapiens Today’s taxonomy still uses Linnaeus’ system

12. Two scientific names for each organism • Linnaeus developed a classification system that used twoGreek words for the name of each organism. • This two-word naming process is often referred to as binomial nomenclature. • These Greek names are used around the world which prevents confusion caused by the various languages. • Using these scientific Greek names also prevents confusion when people begin to identify organisms by their common name. • Example: A puma, cougar and mountain lion are all the same animal. Its scientific name world-wide is Felisconcolor.

13. More about scientific naming • The two taxa used in the scientific name are the Genus and the species. These are the last 2 taxa in the main group of 7 which begins with Kingdom. • There are rules to be applied when you write a scientific name. • 1. The genus is given first and it must be capitalized and underlined. (or in italics) • 2. The species name is second. It must begin with a lower case letter and it also must be underlined.(italics) • Example: Homosapiens or Homo sapiens

14. CATS 1. Wildcat 2. Cougar 3. Housecat The genus is called Felis Felissylvestris Felisconcolor Felisdomesticus or Felis domesticus Other examples of scientific names:

15. Taxa Taxonomy Greek/Latin Aristotle John Ray Carolus Linnaeus Species Kingdom Phylum Class Order Family Genus Binomial Nomenclature Review of the key terms

16. Plato Aristotle (384-322 BC)

17. Homework • Page 103 Question #5,6 • Page 104 Question # 17,22