The Cell Theory

In 1590, the first microscope was made by Zacharias Janssen, a Dutchman. He was the first to use two magnifying glasses to make one larger image- a COMPOUND microscope.

In the mid 1600’s, Anton Van Leeuwenhoek (another Dutch guy) made a microscope that could magnify 270 times.

He was the first person to see microscopic life Van Leeuwenhoek looked at pond water, and called the things he saw “wee beasties”. He was the first person to see microscopic life This is a picture of Van Leeuwenhoek’s microscope.

Cells were discovered in 1665 by Robert Hooke (an Englishman) Cells were discovered in 1665 by Robert Hooke (an Englishman). He sliced a cork and looked at it under a microscope.

This is the actual 300 year old drawing that Hooke made of the cork. Hooke called the little empty boxes he saw “cells”, because they reminded him of prison cells. This is the actual 300 year old drawing that Hooke made of the cork.

Much later, in 1838, Matthias Schleiden (Germany) studied plants under a microscope. Schleiden concluded that all plants are made of cells.

A year later, Theodor Schwann (Germany) concluded that all animals are made up of cells.

15 years after, another German, Rudolf Virchow said that new cells do not form on their own, but come from other cells.

This was a ground breaking theory This was a ground breaking theory. After all, most people still believed in spontaneous generation.

The ideas of Schleiden, Schwann, and Virchow were combined into the Cell Theory: 1. All organisms are made up of one or more cells 2. Cells are the building blocks of all organisms (“the legos of life”) 3. All cells come from cells that already exist