Education is an important aspect of life as a means of forming quality human resources. Quality human resources are characterized by the ability of individuals to manage, use and develop thinking power including creative thinking. Creative thinking skills need to be trained and developed because it is the life skills needed to solve a problem, find and find alternative solutions to problems, and the ability to formulate problems, make guesses and be able to evaluate, and communicate results. Creative thinking has four aspects or indicators: fluency, flexibility, originality and elaboration. One way to exercise creative thinking skills is to use guided inquiry-based learning because through inquiry or discovery learning, students will be trained and accustomed to discovering new concepts or knowledge through a hands-on and mind-on activity process. Students are required to solve problems with intensive guidance from the teacher. Guided inquiry is suitable to be applied in science learning especially in the field of biology, because science lessons are related to the process of discovery involving skills in solving problems, understanding concepts, and their applications.

The purpose of this study is to train students' creative thinking skills through guided inquiry-based learning on pteridophyta material. This type of research is development research that is developing learning devices that aim to obtain a learning device that is feasible to use so that it can train the ability to think creatively. Development of learning devices using 4-D models. The research subjects were class X of Ta’miriyah High School Surabaya. The results showed that creative thinking skills can be trained using guided inquiry-based learning. These results are based on the validity, implementation, and effectiveness of learning devices that have been developed. Validated learning tools include: learning implementation plans, student activity sheets, and creative thinking ability test instruments.

The planned implementation of validated learning has a score of 3.63 with a very valid category while the average percentage of agreement between the two validators is 90.9%. The average results of the validation of the activity sheet consist of three aspects: 1) the content aspect gets a score of 3.87 with a very valid category, 2) the language aspect gets a score of 4 with very valid categories, 3) the presentation aspect gets a score of 3.7 with a very strong category valid, and 4) aspects of learning characteristics with the guided inquiry scored 3.75 with a very valid category with a percentage of agreement 95.4%. Instrument ability shows an average yield of 3.5 from the material aspect with a very valid category, while from the construction aspect it gets a score of 3.6 with a very valid category, and from the aspect of the language it is declared very valid because it scores 3.6 with a percentage of agreement of 88.6%. Whereas coercion is 3.6 with a very good category.

The creative thinking ability assessment sheet in this study was independently developed by researchers with reference to four measures of creative assessment namely fluency, flexibility, originality, and elaboration. The results of the analysis of the assessment of creative thinking skills increased student scores from the average pretest of 41.7 with the less creative category to the posttest average of 65.4 with the category of quite creative, and the value of N-Gain with an average of 0.43 by category is being Based on the results of the analysis of creative thinking skills, the average score in general has increased from 1.50 to 65.4. The conclusion of this study is the application of guided inquiry-based learning tools can train students' creative thinking skills.