A Mini-Lesson

PRIMATE CLASSIFICATION
2006

Larry Flammer

PDF version of this lesson outline

EVOLUTION

 SYNOPSIS

 CONCEPTS

1. The groups-within-groups hierarchical pattern of Linnaean classification is a result of both extinction and branching from common descent.

2. The outline-hierarchy reflects a basic boxes-within-boxes structure for the classification of organisms.

3. Classification of organisms is based on evolutionary relationships.

4. How primates are categorized, and how they are related.

TEACHING STRATEGY

A VIVID & DRAMATIC INTRODUCTION TO THE CONCEPT:
Otain a collection of cardboard boxes in widely ranging sizes, from extremely large (check shoestores, department stores, appliance stores), all the way down to tiny pillboxes. You can label (In large balck letters) the largest megabox "ANIMAL KINGDOM." Find at least a few somewhat smaller baxes that will all just fit into the Kingdom box. Label these with "PHYLUM: VERTEBRATA" and/or the names of two other phyla. Find at least 3 smaller boxes that will all fit into one of the PHYLUM boxes (I like to use the PHYLUM: ARTHROPODA for this one). And so on, building a nested series of boxes, continuing down: CLASS - ORDER - FAMILY - GENUS - SPECIES, with 2-3 boxes for each level. You could use a bunch of fruit flies in one of the species boxes (make it clear, so you can show the students).

1. The lesson can be used as part of a unit on classification especially in a human-oriented biology course. In this context, this lesson helps to illustrate the nature of a hierarchy, as used in classification.

2. This could also be used at any time primate relationships, primate classification (and the human placement in this context) becomes a matter of interest, and needs clarification.

3. Follow the directions, listing specific primates in their appropriate boxes on the separate worksheet (see the "key" if further clarification is needed). To see the key, send request with your school email address to the WEBMASTER. You can show slides of various primates, taken at zoos, and/or photocopied from Google Images or pictures in books. You can also show videos or films which present at least two or three different primates, preferably a large sampling of primates from different groups. Students could also be asked to search the web or library books for other examples, pictures, etc., and share with the class.

4. Use the "boxes-within-boxes" array as a starting point to draw an evolutionary "tree" backwards in time (on an overhead transparency of the completed boxes works best). See key. This is an excellent way to show students how classification relates to evolution and evolutionary "trees". Likewise, the concept of "common ancestors" occupying the points of divergence can be easily explained.

Another way to show this is with the Macroevolution/Classification Diagram.

5. You might also find it interesting to your students to point out a few of the shared characteristics of some of the groups. For example, all primates typically have finger nails, and grasping hands/feet, while other mammals typically do not; also, primates are unique among mammals in that they can see all colors; monkeys typically have tails, hominoids (apes and people) do not; new-world monkeys (in Central and South America) tend to have long grasping ("prehensile") tails, old-world monkey tails are generally shorter and not prehensile. An alternative to this would be to ask your students to search the web and/or library to find and share the distinguishing features of primates and their sub-categories, and find pictures that show those distinguishing features.

Two excellent lessons on the ENSI site that explore primate classification and evolution further are "Molecular Sequences and Primate Evolution" and "Nuts & Bolts Classification - Arbitrary or Not?" This latter lesson is especially important because it exposes a very common and widely taught myth about classification. It is highly recommended to include in any unit on classification.

6. You might want to develop a series of questions to see if your students truly understand what the diagram tells us. This could be done as part of the worksheet, or as a quiz for assessment. For example, you could ask:
---- a) Which level(s) contain the greatest number of species.
(answer: primates...or mammals, if they look at the outline format);
---- b) Which level(s) contain the least number of species (answer: could be any of the levels not further divided: prosimians, ceboidea, cercopithecoidea, hylobatids, pongids, gorillins, panins or hominins; no way to tell which of these from information given);
---- c) Which three groups are most closely related, or biologically most alike? (answer: gorillins, panins and hominins, the only three shown as subfamilies, the lowest group level shown here, all in the same family: hominidae).

7. If your students seem to need further work on this concept, provide them with an outline hierarchical list of amphibian taxa and examples of each (or use another group for which you have access to their classification taxa). Ask them to make a "boxes-within-boxes" diagram, similar to what was done with the primates, and then (possibly), answer some probing questions (similar to the ones above).

8. NEW TAXONOMY: This classification of primates is based on accumulated studies in genetics and molecular biology all pointing to the need to revise the previous classification scheme (formerly used for this lesson). Students may encounter resources(textbooks, internet, etc.) that still use the earlier classification scheme (where all the apes are placed in a category separate from humans). References to "formerly..." reflect that older taxonomy. Students should be made aware of the older system, but encouraged to use the most recent system (detailed in this lesson). CLICK HERE FOR DETAILED DISCUSSION.

 ATTRIBUTION

Some of the ideas in this lesson may have been adapted from earlier, unacknowledged sources without our knowledge. If the reader believes this to be the case, please let us know, and appropriate corrections will be made. Thanks.

1. Original Source: Larry Flammer, 7/95

2. Reviewed / Edited by: Martin Nickels, Craig Nelson, Jean Beard: 12/15/97

3. Edited / Revised for website by L. Flammer 9/98;
Revised again to reflect biological relationships based on recent studies and reports in genetics and molecular biology: March 2006.