Anton Van Leeuwenhoek, known as the father of microbiology, was the first to observe bacteria in 1676. He used one of the first compound microscopes and found what he called "cavorting beasties" in pond water.
Anton van Leeuwenhoek also used microscope technology to study the process of reproduction. He was the first to observe both sperm and eggs of several species. While Anton van Leeuwenhoek was the first to observe live single celled organisms, called microorganisms, he was not the first to observe cells. Robert Hooke first viewed cells by looking at slices of cork under a compound microscope in 1663. He saw repeating structures with the appearance of prison cells and as a result named the structures "cells".