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Spontaneous Generation
Aristotle's Theory Aristotle thought there were four elements and that the properties of living organisms were due to the mixture of earth, air, fire and water, each of which is a principle of hot, cold, dry and wet. -
First Mircoscope Invented by Janssen
Janssen Microscope LinkJanssen invented the first basic, compound microscope. Without this invention, people would have never seen cells. -
Discovery of Photosynthesis
Van Helmont's DiscoveryJan Baptist van Helmont carried out an experiment by growing a willow tree in a pot for five years. At the end of this period the tree had increased in mass by about 165 pounds, but the mass of the soil had changed little. Van Helmont believed that water was the source of the extra mass and the plant's source of life. This process was then later known as photosynthesis. -
Hooke's Law
Hooke's LawRobert Hooke wrote Hooke's Law, which is the law of elasticity. Hooke also wrote Micrographia, the first book describing observations made through a microscope. Hooke was the first person to use the word "cell" to describe the basic unit of life. -
Discovery of Bacteria
Anton Van Leeuwenhoek DiscoveryAnton Van Leeuwenhoek was the first to see and describe bacteria. He used his lenses or microscopes to study a variety of things, both living and non-living, -
Oken's Theory of Evolution
Oken's TheoryLorenz Oken believes plants and animals are made up of tiny living `infusoria' which leas to the cell theory. He suggests a form of cell theory in a book called Die Zeugung (The Conviction). Oken states that “all organic beings originate from and consist of vesicles or cells". Oken came up with a new system of animal classification that demonstrated the path of evolution. -
Brown's Dicovery of the Nucleus
Brown's DiscoveriesRobert Brown discovered the nucleus in plant cells and what it looked like. Also he dicovered how the cytoplasm functions and the difference between gymnosperms species and angiosperms species. -
Schleiden's Cell Theory
Schleiden's Cell Theory Matthias Schleiden determined that all plants are made up of cells. He also recognized the importance of the cell nucleus and identified its role in cell division. He discovered all plant tissues are composed of cells and that plants come from a single cell. He stated that the cell is the basic building block of all plant matter. -
Schwann's Cell Theory
Schwann's cell TheoryTheodor Schwann discovered pepsin, the digestive enzyme, and membrane tissues, of animals. He thought yeast were tiny plant-like organisms, and suggested that fermentation was a biological process. He stated that all living things, like plants and animals, are composed of cells in.He believed that new cells form from pre-existing cells. His discoveries and thoughts created the Cell Theory. -
Von Roelliker's Discovery of Sperm and Eggs
Von Roelliker's DiscoveryAlbrecht von Roelliker realized that sperm cells and egg cells are also cells. -
Virchow's Cell Theory
Virchow's Beliefs and DiscoveriesRudolf Virchow believed that disease comes in cells, not in tissues, organs, or entire organisms and that every cell comes from another cell. Virchow’s greatest accomplishment was his observation that a whole organism does not get sick, only certain cells or groups of cells do.He was the first person to recognize leukemia. He also believed that a diseased tissue was caused by a breakdown within the cells and not from an invasion of a different organism. His beliefs created the Cell Theory. -
Pasteur's Germ and Disease Theory
Pasteur's Germ Theory Louis Pasteur worked with the wine growers of France, helping with the fermentation process to develop a way to kill germs. Pasteur then worked in the textile industry finding a cure for a disease affecting silk worms. He also found cures for chicken cholera, anthrax and rabies. Pasteur tried hard to convince surgeons that germs existed and carried diseases, and dirty tools and hands spread germs and therefore disease.
