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What's in a Name?

Grade Level




These two activities introduce students to scientific taxonomy and using, as well as creating, dichotomous keys. The first activity models the dichotomous key by having the students determine the identity of polar species of the Order Pinnipedia. The second activity brings a bit of the background in how scientific naming is done and leads the students into creating penguin Families based on physical characteristics. The students create the Family names using provided Latin and Greek root words as "building blocks" toward names that describe the family members.

Taxonomy and using a dichotomous key to classify organisms are two concepts that students need to understand in Biology. When asked to use scientific names, though, students are often intimidated since many names are long and strange sounding. Penguins are a favorite topic of students. There are only 18 species in the entire world, making them a manageable number to use. There is only one Family in the Order Sphenisciformes although there are 6 genera and there are at least three distinct body types. By using Latin and Greek root words to describe each new Family they create, students can see how scientific names usually relate to the animals being named. By creating a dichotomous key, the students can more readily understand how they work.

Grade Level/Discipline
Middle School through High School

Using the high interest generated by polar animal species

  • To use a dichotomous key to identify animal species
  • To create a dichotomous key
  • To create scientific Family names using the same word roots as used by taxonomists
National Standards

Teacher Preparation for Activity
Pre-activity set-up
Copy Student Masters. Penguin pictures may be copied onto tag board for easier manipulation when grouping.

Student Masters on Pinnipedia Pandemonium; Classy Penguins; Latin and Greek word roots; Pinnipedia pictures; Penguin pictures and descriptions

Time Frame
One class period

Teaching Sequence
Engagement and Exploration (Student Inquiry Activity)
Students use a dichotomous key to determine the species of polar Pinnipedia. Students should cut out and arrange the various pinnepeds by Family once the identities have been established.

Explanation (Discussing)
Discuss with students what characteristics they felt scientists used to group the pinnipeds in this manner. Determine the meanings of the Family names by looking the Parts of the names up in the word root chart. Discuss with students the history of taxonomy as developed by Carolus Linnaeus and the rules established for scientific names. Model designing a dichotomous key by using common objects such as pens and pencils.

Elaboration (Polar Applications)
Students create at least three Families for the 18 species of penguins. Family names should be developed by using Latin and Greek root words. Students then develop a dichotomous key to identify the Families and individual penguin species.

Exchange (Students Draw Conclusions)
Students share the characteristics used to determine different families and come to consensus on how many families there should be and proper names for these families based on characteristics and root words.

Evaluation (Assessing Student Performance)
Dichotomous key product should be graded on completeness, proper flow, and logical characteristics used for identification of families and species. Names should be evaluated on logical use of root words based upon physical characteritics.

Besse Dawson
Pearland High School
3775 S. Main Street
Pearland, Texas 77581



Student Reproducible Masters


Scientists use dichotomous keys to help them determine the exact species of an organism. Dichotomous means two choices. Either the organism fits into one choice or the other given. You move to the step number given. As you move down through the choice steps, eventually your organism should be described and named.

The following pictures of the Order Pinnipedia (seals, walruses, sea lions, etc.) are described in the key. Not every organism on the dichotomous key is pictured.

In this exercise, only the common name is given.


  1. What characteristics were used in the key to describe the pinnipeds?
  2. Use the Greek and Latin root names to determine what "pinni" in pinniped means.
  3. To what do you think "ped" refers?
  4. What part of the animal do you think distinguishes it (makes it different from) other types of animals, such as a dolphin?
  5. What parts of the anima}s were the hardest to figure out? In other words, what sections of the key did not work as well for you? Is there a way the key could have described that part better? How?
Dichotomous Key for Polar Pinnipeds

1. A. Long tusks - large - up to 1,215 kg Family Odobenidae Walrus
B. No long teeth extending beyond mouth Go to 2
2. A. Head with small ear flaps. Able to walk with hind flippers. Family Otariidae Go to 3
B. Head with small holes only at eardrum Family Phocidae Go to 9
3. A. Rounded noses, short front flippers, rough fur Go to 4
B. Pointed noses, long front flippers & thick fur Go to 5
4. A. Sleek, agile high forehead California sea lion
B. Stocky, low forehead Northern sea lion
5. A. Back and sides gray to brownish w/ high forehead Go to 6
B. Very short snout Go to 7
6. A. Head withcrest Subantarctic fur seal
B. Head without crest Antarctic fur seal
7. A. Black with reddish belly Northern fur seal
B. Back only or entire body gray Go to 8
8. A. Fairly evenly gray all over Juan Fernandez Fur Seal
B. Gray back and gingery belly South American Fur Seal
9. A. Heavily built, male w/large nose capable of ballooning Go to 10
B. No large nose pouches Go to ll
10. A. Large body grayish brown all over- no markings So. Elephant seal
B. Body mottled with dark brown or black markings Hooded seal
10. A. Body with large, more defined markings Go to 12
B. Body with spots, mottled or no markings Go to 13
12. A. Creamy body with dark head and circular dark patch on back Harp seal
B. Dark body with buffy rings around neck and flippers Ribbon seal
13. A. Large heavily bodied Go to 14
B. Small to medium bodied - may have chin stripes Go to 16
14. A. Heavy lower jaw - dark back with spotted side and belly Leopard seal
B. Long snout but small lower jaw Go to 15
15. A. Body patterned with little to heavy patches and lines Gray Seal
B. Body Grayish brown- large, long and smooth whiskers Bearded Seal
16. A. Mottled patterns on body Go to l7
B. Body coloration with little or no mottled areas Go to 18
17. A. Barrel shaped body - mouth line up-turned - patches on sides and belly Weddell Seal
B. Highly variable patterns - mottled spots on back and belly Harbor Seal
18. A. Slim body - elongated snout w/tip tilt up - creamy color Crabeater Seal
B. Plump w/ small head - dark back and silver belly - stripes on chin Ross Seal

Classy Penguins

The man who established how scientific names should be created was Carolus Linnaeus. He chose to use Latin roots of words in naming organisms. He even "Latinized" his own name which was onginally Carl Von Linne' Linnaeus used common traits of organisms to group them. Some of the rules Linnaeus established were that:
  1. Organisms should show genetic relationships to each other through the genus name.
  2. The species name, made up of the genus and the trivial names, was to further descnbe the organism.
  3. Only the genus Is capitalized
  4. The entire scientific name should be italicized or underlined
At present, there is only one Family to which all the penguins belong. Some scientists believe that the penguins should have at least three Families or subfamilies to accommodate the differences between the penguins.

How should the world's penguins be classified?

Penguin illustrations, list of Latin and Greek roots of words


  1. Carefully observe the illustration of all the penguins.
  2. Note any repetition of traits such as body size, feather pattems, beak shapes, or color.
  3. Common traits can be used to create a dichotomous key to identify penguins. Your task is to create three or more Families for the penguins based upon their physical characteristics. You will also name those Families by using Latin and/or Greek word roots so that each name reflects the characteristics of the penguin Family.
  4. Use the following format to create a key that anyone could use to identify and classify the penguins. The numbers must lead the user from one step to the next. One cannot skip down to a step without a "Go to" command.

    1a. Has trait "X" Family Cephalchromis** Go to 2
    1b. Has trait "Y" Family Lithoject** Go to 5
    2a. Has trait"Z" Family Minipeds** Goto 14
    2b. Has beak of another color Go to 3
    3a. Has black beak Penguini negris*
    3b. Has other colored beak Go to 4
    4a. Has purple beak Penguini lavendatis*
    4b. Has spotted beak Penguini punctatis*
    5a. Has . ( Now begin describing all the traits that separate the different "Y" trait penguins. I just guessed at 2a's "Go to 14" You would actuaily use whatever number came after you finished keying all the "Y" trait penguins )

    * Made up names. You will use the correct scientific names from the list your teacher has.

    ** Made up names - You will make up your own. HlNT:Use the word roots to create Family or Subfamily names.

Compare your classification key to those of others around you. Dld you plck out the same charactenstics as the others? If not, what were the tralts you picked out versus the others?

How do scientists decide to what Family an animal belongs?

What problems can this method cause in classifying animals?

What method for classifying are scientists now using? Do you think this will be more accurate? Why or why not?

We look forward to hearing from you! Please review this activity.

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