In the 1670–1680s, Antonie van Leeuwenhoek, a Dutch scientist, made major contributions to the field of microscopy which revolutionized the understanding of biology.

Using microscopes of his own design, equipped with powerful lenses that could magnify objects up to 300 times, van Leeuwenhoek became the first person to observe and describe microorganisms, which he referred to as “animalcules.” His discoveries included bacteria, protozoa, and sperm cells, all of which had never been seen before. Van Leeuwenhoek meticulously documented his findings and shared them with the Royal Society of London, leading to a widespread recognition of his work.

Van Leeuwenhoek's pioneering observations opened up a new world of microscope life and laid the foundation for the field of microbiology, fundamentally changing how scientists understood the complexity of living organisms.