AP BIOLOGY

Detailed explanation-1: -It states that all the living beings whether plants or animals are composed of cells that are from pre-existing cells. However, they failed to explain how new cells are formed. Rudolf Virchow(1885) modified the cell theory and concluded that new cells develop from the division of pre-existing cells.

Detailed explanation-2: -Rudolf Virchow modified the cell theory and gave the concept of ‘Omnis cellule e cellulae’-which means new cells develop by the division of the pre-existing cells. This is called the theory of cell lineage or common ancestry.

Detailed explanation-3: -According to the final theory, all living organisms are composed of cell & cell products. And, all cells arise from pre-existing cells. Rudolf Virchow modified the cell theory by Schleiden and Schwann because it did not tell about how cells were formed.

Detailed explanation-4: -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. Their theory accepted the first two tenets of modern cell theory (see next section, below).

Detailed explanation-5: -The third part, which asserts that cells come from preexisting cells that have multiplied, was described by Rudolf Virchow in 1858, when he stated omnis cellula e cellula (all cells come from cells).