Biology 1222 or 1223;
Chemistry 1050 or the former Chemistry 1020 or 023;
plus 1.0 additional course, with no mark in these principal courses below 60%.

Additional requirements (which may be counted towards the 3.0 principal courses):
1.0 courses from: Calculus 1000A/B or 1100A/B and one of Calculus 1201A/B, 1301A/B, 1501A/B, Linear Algebra 1600A/B, Statistical Sciences 1024A/B; or Mathematics 1225A/B and 1229A/B or the former Mathematics 030. 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.
0.5 course from: Earth Sciences 4431A/B, 4440A/B, 4462A/B.
0.5 course: Chemistry 2210A/B or the former Chemistry 226a/b.
0.5 course from: Biology 2244A/B, 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, the former 327b, 402a, Pharmacology and Toxicology 3560A/B, 4630A, the former 460a/b, the former Microbiology and Immunology 450b.
0.5 course from: Political Science 2137, 2235E, Philosophy 2033A/B, all Geography courses at the 2000 level or above, Biology 4243G.
1.0 course from: Earth Sciences 4490E, or Environmental Science 4970F/G and 4971F/G, with a mark of at least 70%.

Note: If Political Science 2137 or 2235E is chosen the module will consist of 11.0 courses