Abstract This research motivated by the findings of learning obstacles experienced students in material around square. This is known based on the results of test questions conducted during preliminary study to fourth grade elementary school students. To overcome learning obstacles experienced by students, researchers will design a didactic design. The purpose of this study is to describe the didactic design on the material around square and describe the students' responses the implementation of didactic design. The didactic design can be interpreted learning design that emphasizes the didactic aspect, namely the teacher's teaching method. This study uses method with a Didactical Design Research (DDR) research design consisting of three research stages, namely a prospective analysis of the didactic situation before learning (prospective analysis) in the form of a Hypothetical Didactic Design including ADP (Pedagogical Didactic Analysis), metapedadidactive analysis, and retrospective analysis (retrospective analysis), with data collection techniques used in the form of interviews, observations, and attitude scales. The research subjects were 26 students in grades IV and VI and 1 teacher for grade IV at SDN 1 Sindangrasa. Based on results of study, through application of the didactic design carried out in stages I and II, can help overcome learning obstacles experienced by students in the material around a square. This is shown from the students' responses on the attitude scale, results of the LAS (Student Activity Sheet) work and interviews with teachers. In addition, didactic design is able to create a fun and meaningful learning atmosphere for students. Keywords: learning obstacle, didactical design research, square, meaningful learning, LAS Abstrak Penelitian ini dilatarbelakangi oleh adanya temuan learning obstacle yang dialami siswa pada materi keliling persegi. Hal ini diketahui berdasarkan hasil soal tes yang dilakukan pada saat studi pendahuluan kepada siswa kelas IV Sekolah Dasar. Untuk mengatasi learning obstacle yang dialami siswa, peneliti akan merancang sebuah desain didaktis. Tujuan dari penelitian ini adalah untuk mendeskripsikan desain didaktis pada materi keliling persegi serta memaparkan respon siswa dan guru terhadap implementasi desain didaktis tersebut. Desain didaktis dapat diartikan sebagai desain pembelajaran yang lebih menekankan pada aspek didaktik yakni cara pengajaran guru. Penelitian ini menggunakan metode Didactical Design Research (DDR) yang terdiri dari tiga tahap penelitian, yakni analisis situasi didaktis sebelum pembelajaran (prospective analysis) berupa Desain Didaktis Hipotesis termasuk ADP (Analisis Didaktis Pedagogis), analisis metapedadidaktif, dan analisis retrospektif (retrospective analysis), dengan teknik pengumpulan data yang digunakan berupa wawancara, observasi, dan skala sikap. Subjek penelitian yaitu 26 siswa kelas IV dan VI serta 1 guru kelas IV SDN 1 Sindangrasa. Berdasarkan hasil penelitian, melalui penerapan desain didaktis yang dilakukan pada tahap I dan II dapat membantu mengatasi learning obstacle yang dialami siswa pada materi keliling persegi. Hal ini ditunjukkan dari respon siswa pada skala sikap, hasil pengerjaan LAS (Lembar Aktivitas Siswa) serta wawancara terhadap guru. Selain itu, desain didaktis mampu menciptakan suasana pembelajaran yang menyenangkan dan bermakna bagi siswa. Kata kunci : hambatan belajar, desain didaktis, persegi, pembelajaran bermakna, LAS
Freshwater ecosystems have been playing important role in development and maintenance of human civilization. Present study depicted the planktonic and ichthyofaunal biodiversity of Suleman Mountain Range, Dera Ghazi Khan Region of Pakistan. Water quality was assessed by analyzing physico-chemical parameters and the ichthyofaunal status of the region was assessed by calculating abundance and diversity of fish fauna. The fish health status was estimated by measuring several morphometric characteristics and condition factor. The analysis of TDS, pH, CO2, CO3-2, HCO3-1, TA, TH, Na+1, Ca+2, Mg+2, Cl-1, SO4-2, EC and SAR showed significant site variations while water temperature, light penetration, pH, DO and CO2demonstrated the significant seasonal variations. Out of 119, 83 phytoplankton and 36 zooplankton genera were recorded wherein chlorophyta was the most abundant with (RA= 28.80%) and xanthophyta was the least (RA = 0.87%) while Protozoa was the most occuring with (RA = 11.57%) and cladocera was the least with (RA = 0.80%). Twenty fish species were explored in which Tor macrolepis was the most and Labeo calbasu was least abundant in the region. The family Cyprinidae was found to be most abundant and dominant in Suleman Mountain Range, Dera Ghazi Khan, Region while three fish species endemic to Pakistan namely Barilius pakistanicus, Labeo dyocheilus pakistanicus and Salmophasia punjabensis were also observed from this experimental area. Total length ranged from 7.80-31.0 cm for Tor macrolepis, 8.08-17.20 for Schizothorax plagiostomus, 9.0-20.5 for Labeo diplostomus, 9.30-23.60 cm for Labeo dyocheilus pakistanicus, 8.00-14.30 cm for Cyprinion watsoni, 10.30- 18.90 cm for Ompok pabda and 9.00-14.10 cm were calculated. Similarly, wet body weight ranged from 5.20-301.90 g for Tor macrolepis, 7.05-67.08 g for Schizothorax plagiostomus, 5.50-90.0 g for Labeo diplostomus, 10.20-125.0 g for Labeo dyocheilus pakistanicus, 7.90-30.70 for Cyprinion watsoni, 8.50-57.0 g for Ompok pabda and 8.60-39.30 g for Garra gotyla were recorded. New records of maximum total length for Cyprinion watsoni (14.3 cm), Labeo dyocheilus pakistanicus (22.50 cm), Labeo diplostomus (22.0 cm) and Tor macrolepis (29.0 cm) were obtained. Condition factors of most fishes were optimum except Ompok pabda. In general, most of the water quality parameters of the studied sites were within suitable range for growth of living organism. The diversity indices value indicated moderate planktonic diversity. However, ichthyofaunal diversity of the region was poor. The morphometric characteristics and condition factor values indicated good fish health.