– 1839: Theodor Schwann and Matthias Jakob Schleiden elucidate the principle that plants and animals are made of cells, concluding that cells are a common unit of structure and development, and thus founding the cell theory.Click to see full answer. Similarly, you may ask, which scientist said all plants are made up of cells? Theodor Schwann Beside above, how did scientists discover that all living things are made of cells? All living things or organisms are made of cells. New cells are created by old cells dividing into two. Credit for developing cell theory is usually given to three scientists: Theodor Schwann, Matthias Jakob Schleiden, and Rudolf Virchow. In 1839, Schwann and Schleiden suggested that cells were the basic unit of life. Also know, who discovered that plants were made of cells? Robert Hooke Which scientist concluded that all living things are made of cells? Matthias Schleiden
