Cell Theory
Cell Theory
• Cell theory states:
1. All living organisms are
composed of cells. They may be
unicellular or multicellular.
Unicellular = single cell
organisms
Multicellular = organisms made
up of more than one cell
http://www.infovisual.info/02/003_en.ht
ml
Cell Theory
2. The cell is the basic unit of structure and
function.
3. All cells come from previously existing cells.
Exceptions: ____________________________
Cell Theory Timeline
• 1665 - Robert Hooke of England looks
through a microscope at a sliver of cork.
• He notices what he calls cells.
• He is the first person to use the word cell
to describe microscopic structures.
http://images.tutorvista.com/content/cell-unitlife/scientist-robert-hooke.jpeg
Cell Theory Timeline
• 1674 - Anton Van
Leeuwenhoek, of Holland,
used microscopes to view
many things including
pond organisms, bacteria
and blood cells. He made
careful sketches of what
he observed.
http://fiskims.edublogs.org/files/2009/09/Leeuwenhoek.JPG
Listed number 1
on the Science
Channel’s 100
Greatest
Discoveries
Cell Theory Timeline
• 1831 - Robert Brown discovers the nucleus of
the cell. He stresses its importance in
fertilization.
http://science.discovery.com/convergenc
e/100discoveries/big100/biology.html
http://www.xtimeline.com/__UserPic_Large/108226/evt110424021800176.jpg
Listed number 2
on the Science
Channel’s 100
Greatest
Discoveries
Cell Theory Timeline
• 1839 - Matthias Schleiden and Theodor
Schwann create cell theory. The theory states
that all living things are made up of one or
more cells. Schleiden publishes his cell theory
applying it to plants, while Schwann publishes
his applied to animals.
Cell Theory Timeline
• 1855 - Rudolf Virchow writes
and publishes his aphorism
omnis cellula e cellula, which
means every cell stems from
another cell. He theorizes
that all forms of disease
come from changes in
normal cells.
http://www.pathguy.com/virchow5.jpg