Download Key Discoveries

It all started with an
invention….
 The first microscope
 Zacharias Jansen, 1595,
Middleburg, Holland
 It launched great leaps in
Astronomy and Biology.
 Some of the first great
observations with it were
made by…
Robert Hooke (1635-1703)
 Designed microscopes
 Discovered and documented
the first “cells” in 1665
 Named them after the cells in
which a monk sleeps.
Antony van Leeuwenhoek
(1632-1723)
 A tradesman from Holland
who became fascinated with
Hooke’s book
 Discovered bacteria, freeliving protists, blood cells, nematodes, etc.
 Became an expert lens grinder and made over
500 simple microscopes
 Acute eyesight and lens grinding skill let him
build microscopes that were capable of 200X
magnification
Beginnings of Cell
Theory
 1838 Mattias Schleiden stated that all plant
tissues consisted of cells
 1839 Theodore Schwann stated that all animal
tissues consisted of cells
 Each conjectured that there was a nucleus
 1858 Rudolf Virchow combined the two ideas
and added that all cells come from pre-existing
cells, formulating the Cell Theory
Rudolf Virchow
1821-1902
Cell Theory
“every cell originates from
another existing cell like it”
 All living things are composed
of one or more cells
 In organisms, cells are the
basic units of structure and
function.
 All cells are produced only from
existing cells.
Cell Theory



1. All living things are made of cells.
2. Cells are the basic units of
structure and function in living things.
(structure = form; function = purpose)
3. Living cells only come from other
living cells.
Cells
 1. The cell is the basic unit of life
 2. Technology furthered the development
of cell theory because the invention of the
microscope allowed cells to be discovered.
 3. The tiny structures that make up cells
are called organelles which means little
organs.