<p>The research is aimed to improve higher order thinking skills students at class X IPA of SMA through the implementation of discovery learning model on the ecosystem subject. This research was a classroom action research which consists of two cycles. Each cycle contains four phases which were planning, acting, observing and reflecting. The subjects were students at class X IPA of SMA totaling 32 students. The data collecting techniques of this research were using test method obtained through essay test, and nontest method obtained through observation, interview, and documentation. The primary data is advanced higher order thinking skill of students with Bloom revised taxonomy to analyzing, evaluating, and creating measured using essays in accordance researchers any material indicators of ecosystem. The Data validate of this research were triangulation method. Analysis of data using qualitative descriptive analysis technique. The Target of research is to increase the higher order thinking skill’s students ≥25. The increase in higher order thinking skills results by the increasing student achievement of the average score of aspects of higher order thinking skills students were: 1)aspect analyzing of 52.66 with the moderate criteria of being at base line be 66.98 with the moderate criteria of being in the cycle I, then the the cycle II into 80,52 with a high criteria, 2)evaluating aspects of 45.83 with low criteria on base line be 64.17 with the moderate criteria of being in the cycle I, then on the cycle II into 73.96 with moderate criteria, and 3)creating aspects of 50,31 with the moderate criteria of being at base line be 68,49 with the moderate criteria of being in the cycle I, then on the cycle II into 76,35 with high criteria. Implication of discovery learning can increase the high order thinking skills students in base line, Cycle I and Cycle II. The score of test each aspect of higher order thinking skill aspect were: 1)analyzing increased by 27,86, 2)evaluating an increase of 28,13 from, and 3)creating increased by 26,04. This conclusion was implementation of discovery learning could improveas much as ≥25 of high order thinking skills students at class X IPA of SMA.</p><p> </p><p>Keywords : higher order thingking skill, discovery learning</p>

This research aims to analyze the understanding of students’ concepts in 9th grade junior high school on genetic material. Mastery of concepts is one of the important aims in the process of learning biology. In this research, it is used case study method with the research design pretest only one group design. The number of samples is 50 9th grade students consisting of 35 female students and 15 male students. The average of sample is 14--15 years old. The research instruments consist of 15 multiple choice questions on genetic material. The results show that the understanding of the concept of most of the students is about -0.19 logit. There are differences in mastering the concept of understanding between male and female students at certain concepts. It is used the Rasch model that can explain well the profile of students' conceptual understanding using output table 3.1 summary statistics: reliability person and separation person. Response patterns are known from person fit and scalogram table, as well as output table 30. Item: dif, between/within is applied to detect question bias both genders. The results of profile in understanding the concept of biology learning on genetic concepts require further researches to be able to improve the learning process so as to elevate the understanding of genetic concepts for 9th grade junior high school students