Discovery of the Cell
It is common knowledge that cells are the basis of all living things. This fact was not always known and in fact was not discovered until the 1660s. Scientists by the names of Robert Hooke and Anton Van Leeuwenhoek made the amazing discovery of cells and their parts.
The compound microscope had just been invented and Robert Hooke decided to observe a piece of cork. He noticed that the cork was made of small structures that reminded him of individual rooms. He called these "rooms" cells. Because the cork Hooke was observing was dead, the cells he observed were also nonfunctioning.
Meanwhile, Anton Van Leeuwenhoek decided to observe living things such as blood and saliva under a microscope. He observed tiny parts within these substances. He named these parts "animalcules" because they resembled animals.
The discoveries made by Hooke and Leeuwenhoek are the basis of what is now known as the Cell Theory. The Cell Theory states that all living things are made of cells, cells are the basic unit of life, and cells only come from preexisting cells.