-
384 BCE
Aristotle
He made the theory that developing organisms go through a series of stages before acquiring their final form. He was the first to theorize that each germ came from another and realized that each gene has a definite parent and a similar offspring. -
Zacharias Janssen
He invented the first compound microscope that allowed scientists to cite and observe cells. He also discovered the idea that all living things are made of cells. -
Jan Baptist van Helmont
He came up with the theory of spontaneous generation which was living things just randomly appeared like magic. -
Robert Hooke
He was the first person to observe cells and actually came up with the name. This led to greater understanding of cells and life. -
Anton van Leeuwenhoek
He is known as "the father of microbiology" and one of the first microbiologists. He made over 500 microscopes. He was observing water closely when he was surprised to see tiny organisms, which was the first bacteria observed by man. -
Lorenz Oken
"All living things originate and consist of cells"
He developed a new system of animal classification based on evolution. Lorenz believed in both the ideas that all living organisms have cells and cells are formed by pre-existing cells. -
Robert Brown
He observed plant cells and discovered/named the nucleus. He stressed its importance in reproduction and recognized its significance as an essential organelle. -
Matthias Schleiden
He observed plants on a microscopic level and realized all plant tissues are composed of cells. Discovered that embryonic plants arise from single cells, cells are the building blocks of plant matter, and that all plants grew through the production of new cells. -
Theodor Schwann
He examined the cellular structure in animal cartilage and determined that cells are the basic unit of life. He also ended controversy that plants and animals were fundamentally different. -
Albrecht von Roelliker
He discovered through the help of powerful microscopes, that the sperm and egg were composed of cells and that humans are formed of cells from beginning to end. -
Rudolf Virchow
He discovered the idea that every cell stems form another cell. Rudolf was the first to demonstrate that the cell theory applies to both normal and diseased cells. He added to the cell theory and strengthened the theory that cells exist from pre-existing cells. -
Louis Pasteur
He proved the cell theory by showing that spontaneous generation does not exist and all cells are formed by pre-existing cells.
