Robert Hooke was an English scientist who is best known for his work in microscopy. In 1665, Hooke published Micrographia, a book that described his observations made with a compound microscope. One of the most important discoveries he made using this tool was the cell.
Hooke’s observations of cork led him to conclude that all living things are composed of cells. He also observed that cells have walls and pores, and that the walls are made up of cellulose fibers. This led him to conclude that plants are made up of cells, which were previously thought to be just one part of plants (the leaves).
Hooke’s work with the compound microscope also allowed him to make important discoveries in the fields of plant physiology and geology. His observations made with this tool helped him develop theories about fossils being formed by natural processes rather than being created by God as evidence of creationism. He also developed ideas about how earthquakes could occur due to shifting tectonic plates below ground level; these ideas would later be proven correct by others who studied earthquakes more closely than he did at this time period before his death in 1703 at age 67