Biology 1001A or 1201A and 1002B or 1202B or the former Biology 1222, 1223;
Chemistry 1100A/B and 1200B or the former Chemistry 1020, 1050;
Plus 1.0 additional course from: Calculus 1000A/B or 1100A/B and one of Applied Mathematics 1201A/B or the former Calculus 1201A/B, Calculus 1301A/B or 1501A/B, Mathematics 1600A/B or the former Linear Algebra 1600A/B, Statistical Sciences 1024A/B; or Mathematics 1225A/B and 1229A/B. This requirement must be completed by the end of second year.

5.0 courses: Earth Sciences 2200A/B, 2201A/B, 2206A/B, 2220A/B, 2230A/B, 2250Y, 2260A/B, 3314A/B, 3340A/B, 3341A/B.
1.0 course from: Earth Sciences 4431A/B, 4440A/B, 4462A/B.
0.5 course: Chemistry 2210A/B.
0.5 course from: Biology 2244A/B, or the former Statistical Sciences
2122A/B.
0.5 course: Biology 2485B.
0.5 course from: Geography 2153A/B, 2154F/G.
1.0 course: Environmental Science 3300F/G, 3350F/G.
0.5 course from: Biology 2217B, 2290F/G, 2404A, 2483A, 2484A, 3220Z, 3421F, 3435F/G, 3445F, 3446B, 4405F/G, Pharmacology 3560A/B, 4630A.
0.5 course from: Political Science 2137, 2235E, Philosophy 2033A/B, all Geography courses at the 2000 level or above, Biology 4243G.
0.5 additional course from: Earth Sciences 2240F/G or 2241A/B, 3320A/B, 3369A/B, 3370A/B, 4431A/B, 4440A/B, 4444A/B, 4462A/B, the former Chemical and Biochemical Engineering 3363A/B, Civil and Environmental Engineering 4405A/B.