Student Exploration: Dichotomous Keys
Vocabulary: dichotomous key, genus, organism, scientific name, species, and traits
Prior Knowledge Question (Do this BEFORE using the Gizmo.)
Jerome is walking through a park when he sees the spider shown at left. How could Jerome find out what type of spider it is?
In the field, scientists often have to identify an unfamiliar organism (living thing). A reliable way to identify organisms is to use a dichotomous key. A dichotomous key is a series of paired statements or questions that lead to the identification of an organism.
The Dichotomous Keys Gizmo™ allows you to use five different dichotomous keys to identify a variety of organisms. To begin, make sure California Albatrosses and Organism A are selected.
Read the two statements at lower right. Which of the two statements most closely matches the characteristics of the bird pictured?
Select that statement and click Next. Continue until you have correctly identified the albatross. If you change your mind about a choice, you can click the Back button. If you incorrectly identify the albatross, you can click the Start Over button and try again.
What is the name of the albatross?
The scientific name is shown in italics. Scientific names have two parts: the genusname and the species name. What is the scientific name of this albatross?
Use a dichotomous key
Get the Gizmo ready:
Make sure the California Albatrosseskeyis selected.
Select Organism B.
Introduction: As you saw on the previous page, a dichotomous key can help you identify an organism using its characteristics, or traits. The keys in this Gizmo use only physical traits, such as feather color, to identify organisms. In some cases, behavioral traits are used in dichotomous keys. For example, some frog species can be identified by their croaks.