M EET THE S CIENTISTS :
D EVELOPING THE C ELL T HEORY
W HAT

IS A CELL ?
The cell is the basic unit of structure
and function in living organisms,
including plants and animals.
A LL LIVING THINGS ARE
MADE OF CELLS
Plants
Animals
TOOL USED TO VIEW
CELLS

The microscope is used to
magnify extremely small objects.
T IMELINE - 1590

Hans and Zacharias Janssen (1590)

Dutch lens grinders

Father and son

Produced first compound microscope
(two lenses)
T IMELINE - 1665

Robert Hooke (1665)

English scientist

Looked at a thin slice of cork through a
compound microscope and observed tiny,
hollow room-like structures

He called them cells, but he only saw the
outer cell walls because the cork cells
were not alive.
T IMELINE - 1680

Anton van Leeuwenhook (1680)

Dutch amateur scientist

Looked at blood, rain water, and
scrapings from teeth through a
simple microscope.

He called the structures he saw
“animalcules”.
T IMELINE - 1838

Matthias Schleiden (1838)

German botanist

Viewed plant structures under a
microscope and discovered that they
were made of cells
T IMELINE - 1839

Theodor Schwann (1839)

German zoologist

Viewed animal tissue taken from
animal organs under a microscope
and discovered the tissue
was made of cells
T IMELINE - 1855

Rudolph Virchow (1855)

German physician

Stated that living cells come only from
other living cells (This is a part of cell
theory.)