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Living Systems. Chapter Three: Classifying Living Things. 3.1 Types of Living Things 3.2 Dichotomous Keys. 3.2 Dichotomous Keys. A dichotomous key is a tool that helps its user identify natural objects like birds, trees, rocks, fungi, and insects.
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Chapter Three: Classifying Living Things • 3.1 Types of Living Things • 3.2 Dichotomous Keys
3.2 Dichotomous Keys • A dichotomous keyis a tool that helps its user identify natural objects like birds, trees, rocks, fungi, and insects. • Dichotomous means "divided into two parts.”
3.2 What is it? • The ghost plant (Monotropa uniflora) lacks the green pigment chlorophyll, which gives most plants their color. How should we classify this species?
3.2 Dichotomous Keys It is difficult to create a key for the kingdoms because there are so many organisms to consider.
3.2 Dichotomous Keys • A dichotomous key turns questions into paired statements.
3.2 Dichotomous Keys • Most dichotomous keys are designed to identify small groups like trees, butterflies, and song birds. Can you suggest a way to tell these arthropod classes apart?
3.2 Dichotomous Keys • Here is one solution…
Ecology Connection Discovering a New Species • There are still remote regions on Earth, even though it may seem like humans have been everywhere.
Activity Making a Dichotomous Key • Scientists who study the characteristics of organisms and their relationships to other organisms are called taxonomists. • Make a dichotomous key to identify your classmates’ shoes.