For those teachers using a case studies approach to inquiry-based learning, the Hemoglobin Case Study for Advanced Science is now available as a means to explore proteins, respiration and mutations. This case study uses a specific allosteric protein to teach students about the evolution of oxygen in the atmosphere and the globin genes that helped organisms survive the changes in the Earth’s atmosphere. Alternate forms of hemoglobin in fetal blood, organisms living in hypoxic environments, and in people with sickle cell anemia are used to teach the basics of genetics, evolution, heterozygous advantage and biochemistry. This case study covers the cardiovascular and respiratory systems through comparative anatomy of phyla and reviews the use of oxygen from ventilation through cell respiration. Skills such as electrophoresis, pedigree analysis, genetic engineering and student-designed experimentation will be taught in the 25 activities contained in this case study. Click on the “samples” or “table of contents” links on the Hemoglobin Case Study page to learn more.