Classification Notes (cont.)

• As we move from kingdom to species, organisms within each taxon become more similar to one another.

• Taxon: A group of similar organisms

How do we classify?• By cell structure, food-getting methods

and metabolism, external coverings.• DNA and genetic code is increasingly

more important.• Classification of organisms is not perfect-

some organisms are reclassified when more is learned about them.

• Some have even suggested adding more kingdoms.

Level of Classificatio

n

Human Domestic Cat

Grizzly Bear

Kingdom Animalia Animalia Animalia

Phylum Chordata Chordata Chordata

Class Mammalia Mammalia Mammalia

Order Primates Carnivora Carnivora

Family Hominidae Felidae Ursidae

Genus Homo Felis Ursus

Species sapiens silvestris (domesticus)

arctos

1. At which taxon do you start to see differences?

2. Which two of the three organisms are more related?

3. At what point do the classifications of the cat and grizzly bear diverge?

Binomial Nomenclature (two name naming)

• Every scientific name is made of two words (binomial)

• First word is Genus is capitalized• Second word is Species name and is lowercase• Genus functions as a noun, Species functions as

an adjective.-Genus: noun-Species: adjective

Examples:Genus Homo sapiens species

Genus Felis silvestris species

Genus Ursus arctos species

Be able to look at a scientific name and determine which two organisms are the most closely related.

Of the three choices below, which two are the most closely related?

I. Red hatII. Blue hatIII. Red ball

Answer: the Red hat and the Blue hat. They are closest related because their nouns are the most similar. The adjective only describes the noun.

Now, which of the following three pairs are the most closely related? Why?

I. Mus domesticus Musca domesticaII. Galleus domesticus Mus domesticusIII. Felis concolor Felis rufus

Answer: Pair 3Genus species of a particular

genus

1. Mus domesticus mouse Musca domestica fly2. Galleus domesticus chicken Mus domesticus mouse3. Felis concolor cougar Felis rusus bobcat

Noun AdjectiveIf someone asks you which organisms are most similar, look for ones with the same “noun” as 1st word.