IB Biology HL case studies
IB Biology HL · Put your knowledge to work in context.
IB Biology HL is the higher-level biology course within the International Baccalaureate Diploma Programme, a two-year pre-university qualification taught in schools worldwide and recognised by universities for admission and credit. It suits students who want a rigorous, conceptually demanding biology foundation - typically those heading toward medicine, biomedical science, ecology, or biotechnology - and who are willing to combine strong content knowledge with statistical and experimental reasoning. The IB Biology HL case studies are 5 cases and about 4,684 words.
1Two cave fish populations: one species, two, or three?
A biospeleology team surveys two limestone caves 40 km apart in the same karst region. Cave A holds a blind, unpigmented fish population living 300 m from the entrance; Cave B holds a similar-looking blind population.
866 words, about 4 min2Highland and lowland rodents: what a common-garden experiment can and cannot show
Two populations of a single rodent species live at 4,200 m in the Andes and at 50 m on the coast. Pups from both populations were raised for six months in one laboratory at sea level on an identical diet, then measured as adults (body mass 210 g vs 205 g).
888 words, about 4 min3Pike, nutrients and a green lake: reading a factorial enclosure experiment
In a eutrophic shallow lake (total phosphorus 95 µg/L), a team suspends sixteen 1 m³ enclosures, each sealed to the sediment. The design is factorial: pike present or absent, crossed with nutrient addition (N and P) or no addition, with four replicate enclosures per treatment.
877 words, about 4 min4Warfarin resistance: a Hardy–Weinberg result that hides evolution
A population of 400 rodents is sampled from a farm before a warfarin baiting programme begins. Genotyping at the VKORC1 locus gives RR 4, RS 92, SS 304, where R is the resistance allele, S the susceptible allele, and R is dominant for survival on bait.
952 words, about 5 min5The amylase IA: a pH optimum that doesn't match the textbook
A Higher Level student investigates the effect of pH on the rate of starch hydrolysis by amylase. She uses 1.0% starch, 0.5% amylase solution, five pH buffers (3, 4, 5, 6, 7) and a water bath set to 37 °C.
1,101 words, about 6 min