KUNCI DETERMINASI ATAU KUNCI DIKOTOM

Introduction

This tutorial provides a comprehensive guide on the concept of determination keys or dichotomous keys, specifically designed for 7th-grade science students. Understanding this topic is essential for identifying and classifying plants and organisms in biology. By the end of this guide, you will learn how to use a dichotomous key effectively and apply it to specific examples such as corn, soybeans, and eggplants.

Step 1: Understanding Dichotomous Keys

• Definition: A dichotomous key is a tool that allows users to identify organisms by answering a series of questions that lead to the correct name of the item.
• Structure: It usually consists of paired statements or questions that describe the characteristics of the organisms.
• Purpose: The main goal is to help classify and identify unknown species based on observable traits.

Practical Tips

• Familiarize yourself with common characteristics such as leaf shape, flower color, and growth habits before using the key.
• Make sure to handle specimens gently to observe their features without damaging them.

Step 2: Creating a Dichotomous Key

• Identify Characteristics: List the observable traits of the organisms you want to classify. For example:
  • Leaf shape (broad, narrow)
  • Flower color (yellow, purple)
• Formulate Questions: Create pairs of statements based on the characteristics. For example:
  • 1A: Leaves are broad → Go to 2
  • 1B: Leaves are narrow → Go to 3
• Continue with Further Questions: Keep branching out until you reach specific identifiers for each plant.

Example

For corn, soybeans, and eggplants, the first few questions might look like this:

1. Does the plant have broad leaves?
   • Yes: Corn
   • No: Go to 2
2. Does the plant have purple flowers?
   • Yes: Eggplant
   • No: Soybean

Step 3: Applying the Dichotomous Key

• Use the Key: Once your key is created, you can use it to identify any of the plants.
• Follow the Steps: Read the statements carefully and follow the path based on your observations.
• Document Your Findings: Write down the name of the plant along with its classification using the key.

Common Pitfalls to Avoid

• Skipping questions or not observing the characteristics closely can lead to incorrect identification.
• Ensure clarity in your questions; ambiguous statements can confuse users.

Conclusion

In conclusion, mastering the use of dichotomous keys is a valuable skill in biology, enabling you to classify and identify various organisms effectively. By following the steps outlined in this guide, you can create your own dichotomous key and apply it to identify plants like corn, soybeans, and eggplants. Practice by answering the provided question regarding these plants in the comments, and enhance your understanding of this essential scientific tool. Happy studying!