Cell theory

Scientists once thought that life spontaneously occurred from nonliving things. Thanks to experimentation and the invention of the microscope, that is now recognized that life comes from preexisting life and that cell come native preexisting cells.

You are watching: What is the smallest unit of a living organism


Micrographia Cover

English scientist Robert Hooke published Micrographia in 1665. In it, he illustrated the smallest complete parts of one organism, which he called cells.

Photograph by Universal history Archive/Universal Images team via Getty Images


In 1665, Robert Hooke released Micrographia, a book filled v drawings and also descriptions that the organisms he viewed under the recently created microscope. The development of the microscope brought about the discovery of the cell by Hooke. If looking in ~ cork, Hooke observed box-shaped structures, i beg your pardon he called “cells” together they reminded that of the cells, or rooms, in monasteries. This discovery led to the advance of the timeless cell theory.The timeless cell concept was propose by Theodor Schwann in 1839. There are three parts to this theory. The very first part says that all organisms room made the cells. The second part states the cells are the straightforward units of life. These components were based upon a conclusion do by Schwann and also Matthias Schleiden in 1838, ~ comparing their monitorings of plant and also animal cells. The third part, which asserts that cells come native preexisting cells that have multiplied, was defined by Rudolf Virchow in 1858, when he declared omnis cellula e cellula (all cell come native cells).Since the formation of classic cell theory, modern technology has improved, permitting for more detailed observations that have actually led to brand-new discoveries about cells. These findings resulted in the formation of the contemporary cell theory, which has actually three main additions: first, that DNA is passed between cells during cell division; second, the the cell of every organisms in ~ a similar species are mainly the same, both structurally and also chemically; and also finally, that power flow occurs within cells.

See more: Girl Hot Rods And Women - 150 Hot Rods & Hotties Ideas


English scientist Robert Hookepublished Micrographia in 1665. In it, heillustratedthe smallest finish parts of one organism,which he calledcells.