Hasibuan, A.A. and Rangkuti, M.N.S. 2026. The Effect of the Problem Based Learning Model on Students’ Communication Skills and Learning Outcomes in Ecosystem Material. Biocaster : Jurnal Kajian Biologi. 6, 3 (Jul. 2026), 1651–1660. DOI:https://doi.org/10.36312/biocaster.v6i3.1176.