In a response to lower test scores in science and mathematics in Australia, the Western Australian Institute of Technology conducted a study to identify high quality science and mathematics teachers in Western Australian schools. This paper describes the teaching practices of one male and one female teacher of biology from two different schools. It identifies those teaching practices which may be considered exemplary and worthy of attention and analysis by other teachers and teacher educators. The study addresses specific aspects of: (1) the intended curriculum; (2) the implemented curriculum; (3) the perceived curriculum; and (4) the achieved curriculum, in terms of the teaching of biology at the high school level. The major focus of these case studies is on the implemented curriculum, particularly with regard to the teachers' classroom organization and management, handling of students from different ability levels, student motivation, and the nature of the academic work. While both teachers were identified as being exemplary, there were differences found in their instructional approaches which tended to be attributed to the personality and teaching philosophy of each teacher. (TW)