Dichotomous Key Exploration
This worksheet helps 7th-grade students understand and apply dichotomous keys for classifying organisms based on their characteristics.
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Dichotomous Key Exploration
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Read each question carefully and follow the instructions to complete the worksheet. This worksheet will help you understand how to use and create dichotomous keys to identify different organisms.
What is a Dichotomous Key?
A dichotomous key is a tool that allows the user to determine the identity of items in the natural world, such as trees, wildflowers, mammals, reptiles, rocks, and fish. Keys consist of a series of choices that lead the user to the correct name of a given item.
1. What is the primary purpose of a dichotomous key?
To describe an organism's habitat
To identify an unknown organism
To explain an organism's evolutionary history
To classify organisms by their size
2. Each step in a dichotomous key presents two contrasting statements, often called a .
3. By making a choice at each step, you are led to the next step or the of the organism.
4. Explain why it is important for the two statements in each step of a dichotomous key to be contrasting.
5. A dichotomous key can only be used to identify plants.
True
False
6. Use the following simple dichotomous key to identify the unknown organisms (A, B, C, D).
Dichotomous Key:
1a. Has wings .................................................................... Go to 2
1b. Does not have wings ................................................... Go to 3
2a. Has antennae ............................................................. Butterfly
2b. Does not have antennae ............................................. Bird
3a. Has more than 4 legs ................................................ Spider
3b. Has 4 legs ................................................................... Dog
Organism A: Has wings and antennae.
Identification:
Organism B: Has 4 legs and no wings.
Identification:
Organism C: Has wings but no antennae.
Identification:
Organism D: Has more than 4 legs and no wings.
Identification: