Biology 2483A Quiz: Evolution.docx

• School: Western University
• Department: Biology
• Course: Biology 2483A
• Professor: Lisa Henry

Document Summary

All variation we see is driven by processes such as natural selection. Trophy hunting & inadvertent evolution: a case study. Bighorn sheep populations have been reduced by 90% by hunting, habitat loss, and introduction of cattle. Hunting is now restricted; permits for a large trophy ram cost over ,000: trophy hunting removes the largest and strongest males the ones that would sire many healthy offspring. In one population, 10% of males were removed by hunting each year, the average size of males and their horns decreased over 30 years of study. Removing major contributors to mating in population, selection. This is also being observed in other species: Rock shrimp are all born male, and become females when they are large enough to carry eggs. Commercial harvesting takes the largest individuals, which are all females. Genes for switching sex at a smaller size became more common, resulting in more females, but smaller females lay fewer eggs.