Classification

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Important Vocabulary

1. Taxonomy: science of classification

2. Binomial nomenclature: two name naming system

3. Prokaryotic: cells without nucleus

4. Eukaryotic: cells with a nucleus

5. Autotroph: organism capable capturing energy from sunlight or chemicals & produces its own food

6. Heterotroph: organism that obtains its energy from food it consumes

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Why organisms are given scientific names--

a. Common names are misleading

b. To study the diversity of life

Slide # 3 Finding Order in Diversity

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jellyfish silverfish star fish

None of these animals are fish!

Some organisms have several common names

Slide # 4

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This cat is commonly known as:

•Florida panther

•Mountain lion

•Puma

•Cougar

Scientific name: Felis concolor

Scientific name means “coat of one color”

Why Scientists Assign Scientific Names to Organisms

Slide # 5 Aristotle: The First to Classify

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Aristotle grouped jellyfish & clown fish together because they lived in the water. However, these organisms are not closely related.

Grouped organisms together that were not related.

System remained unchanged for almost 2,000 years.

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Linnaeus: The Father of Modern Taxonomy

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Carolus Linnaeus

1732: Carolus Linnaeus developed system of classification – binomial nomenclature

a. Two name naming system Genus and species Genus: noun species: adjective Genus capitalized species not capitalized Both names are italicized or

underlined EX: Gray wolf: Canis lupus

Slide # 7

Family

Species

Kingdom

Phylum

Class

Order

Genus

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Linnaeus’s System is Hierarchical

Most Inclusive

Least Inclusive

1. Which of the following contains all of the others?

a. Family c. Class

b. Species d. Order

2. Based on their names, you know that the baboons Papio annubis and Papio cynocephalus do not belong to the same:

a. Family c. Order

b. Genus d. Species

Grizzly bear Black bear Giant panda

Red fox Abert squirrel

Coral snake

Sea star

KINGDOM Animalia

PHYLUM Chordata

CLASS Mammalia

ORDER Carnivora

FAMILY Ursidae

GENUS Ursus

SPECIES Ursus arctos

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Hierarchical Ordering of Classification

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As we move from the kingdom level to the species level, more and more members are excluded – species is least inclusive!

Cladograms verses Phylogenetic Trees

Cladogram: shows where novel characteristics originate that separate one

group from the rest. •“Y” shaped diagram

Phylogenetic tree: shows the paths taken by populations of organisms through many generations and over long periods of time. -- branching

jawless•

••Jawed fish & cartilage

Bony fish; paired fins

Phylogenetic Trees

1. Practice reading a phylogenetic tree

3. The striped skunk most closely related to: ______________________ European otter

4. Cats and wolves are classified in the same ______________ Order

5. Wolves and dogs are classified in the same ________________ Genus

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Using Molecular Data to Classify

1. How closely related one species is to another can be measured by comparing their genes and gene products. (proteins)

2. The more closely related two species are, the more similar their DNA base sequences for a gene (protein).

3. Can compare nucleotide sequence (for a gene) or the amino acid sequence (for a protein)

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Example of Using Molecular Data

The table shows a comparison of some amino acids found in cytochrome c. The two organisms in the table that are most closely related are —

A Q and T C Q and R

B R and S D Q and S Answer: Q & R

Comparing Q & T: 10% difference

Comparing Q & S: 6% difference

Comparing Q & R: 3% difference

Comparing R & S: 9% difference

Comparing R & T: 13% difference

Comparing S & T: 4% difference

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Using a Taxonomic Key

1. Also called a dichotomous key

2. Consists of a series of paired descriptions

3. Begin with the first pair of descriptions; decide which is most appropriate

4. Continue until all the pairs have been exhausted, or until you identify the specimen

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Example of a Taxonomic Key

Worm 1 belongs to which category?A. Acanthocephala C. LumbricusB. Ascaris D. Nais

Answer:

Lumbricus

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