chapter 9 classification the greek philosopher aristotle began classifying organisms more than 2000...

Chapter 9 ClassificationChapter 9 Classification

• The Greek Philosopher Aristotle began classifying organisms more than 2000 years ago

• In the 1600’s, English scientist, John Ray, established the species as the basic unit of classification.

• Our modern system of classification was introduced by Swedish scientist Carolus Linnaeus. He published a book on plant classification in 1753 and a book on animal classification in 1758.

Chapter 9 IntroductionChapter 9 Introduction

• According to Linnaeus– Organisms were classified according to their structure– Plants and animals were arranged into genus and

species, and the categories of class and order were introduced.

– Species were given distinctive two-word names. Linnaeus’ system is still in use today, although with many changes

– Carolus Linnaeus is the Latin translation of the Swedish scientist’s given name, Carl Von Linne

Vocabulary for Section 1Vocabulary for Section 1

• Classification• Kingdom• Phylum• Class• Order• Family• Genus• Species• Taxonomy• Dichotomous Key

Section 1 ContinuedSection 1 Continued

• Please use your text and define the following vocabulary words. Use graphic organizer 9-1 to write your definitions.

• Classification

• Kingdom

• Phylum

• Class

• Order

Chapter 9 Section 1Chapter 9 Section 1

• Classification is about Sorting it all out.• Classification stems from a need to organize

things around us.• It may be nice to know what plants you can eat

and which are poisonous. You may want to know which animals you can eat and which will eat you.

• Classification is the arrangement of organisms into orderly groups based on their similarities.


• Why Classify• There are millions of different living things in our

world.• Making sense of the sheer numbers and

diversity of living things required classification.• Classification makes it easier for biologist to find

answers to many important questions, such as;• How many know species are there?• What are the characteristics of each?• What are the relationships between species?

Section 1 continuedSection 1 continued

• 7 Levels of classification used by biologist

• Kids Prefer Cheese Over Fried Green Spinach

• King Philip Came Over For Grape Soda

• Kingdom, Phylum, Class, Order, Family, Genus, Species.

• Can you name the 7 levels of classification?


• What is the basis for Classification?• Taxonomy: The science of identifying,

classifying, and naming living things.• Initially, taxonomy attempted to classify

organisms only by their shared characteristics.• Later scientist began to realize that evolutionary

changes form a line of descent from a common ancestor. Taxonomy changed to include these new ideas about evolutionary relationships.


• Modern Classification.• Taxonomists today classify organisms based on

presumed evolutionary relationships.• Species with a recent common ancestor can be

classified together.• See figure 4 in the text.• Because of their common ancestor, an ancient

mammal, all four animals are based in the same class…Mammalia


• The bear, lion and house cat, are more closely related to each other than to the platypus. They are all mammals, but only the platypus lays eggs.

• Brown bears, lions and house cats, share a different common ancestor, an ancient carnivore. Thus, they are classified in the same order, Carnivora.


• You can take it even further and compare the lion and the house cat. See page 203 of text.

• Next session we will discuss Naming names and Dichotomous Keys.


• Take time now to fill out the next five vocabulary words on graphic organizer 9-1.

• Family

• Genus

• Species

• Taxonomy

• Dichotomous Key


• Naming Names• By classifying organisms biologists are also able to give

them specific names.• A scientific name for an organism is always the same no

matter how many common names it may have.• The scientific name for the Indian Elephant is a two word

Latin name, Elephas maximus. All scientist know that Elephas maximus is the Indian elephant, and no other species uses this Latin two word name.

• Elephas in this case is the Genus, and maximus is the species.


• Why are scientific names so important?

• Anyone care to hypothesize?

• Does our discussion bring back any previous knowledge?

• Remember the Scientific Method and why certain standards are used, all through the scientific community.


• Dichotomous Keys• Defined it is an aid in identifying unknown

organisms• The dichotomous key consist of several

pairs of descriptive statements that have only two alternative responses.

• By working through the statements the taxonomist can eventually identify the organism.

Section 1 Review ExerciseSection 1 Review Exercise

• 1. Why do scientist use the scientific names for organisms?

• 2. Explain the two parts of a scientific name?• 3. List the seven levels of classification?• 4. Describe how a dichotomous key helps to

identify unknown organisms.• 5. Study the figure on the bottom of page 207.

Which plant is the closest relative of the hibiscus? Which plant is most distantly related to the hibiscus? Which plants have seeds?

chapter 9 classification the greek philosopher aristotle began classifying organisms more than 2000...

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