The bilingual education has just started in Brazils public schools. This paper is a didactic sequence of biology bilingual lessons about ecologic relationships. This didactic sequence was applied in the first year of a bilingual education in the only public English and Portuguese bilingual high school in Brazil. The aim of this work is to develop and apply a didactic sequence capable of developing the scientific literacy through the bilingual education associated with Problem Based Learning. This didactic sequence was applied in a class of 30 students. It was divided in three lessons. In the first lesson the students were divided in groups and received a graphic of a predator pray interaction. They also received a text in English with information about ecologic relationships which also asked what was the relationship between the animals presented in the graphic above. The students analyzed the graphic then raised hypothesis of what could be happening. In the second lesson the students searched online to verify if theirs hypothesis were correct and to find answers for the question proposed. In the third lesson the groups got together and discussed about their results and wrote a final document with the answers for the problem proposed. The tools used to acquire information about the didactic sequence were: researcher’s diary, survey, interview and documents developed by the students. Only one group could explain the problem with the initial hypothesis. During the second lesson almost all the groups figured the answer, which was widely discussed during the third lesson. The ecological relationships were deeply studied by the students to achieve the final answer. This methodology was successful for developing the scientific literacy with most of the students and also concluded that the quality of learning is directly associated with the challenges created by the problem.