The Development of the Cell Theory (Timeline) by Ada Archibald

334 BC - Aristotle

aav741407 — 2024-02-07 13:49:00 UTC

Aristotle (384-322 BC) was an Ancient Greek philosopher and polymath. His writings cover a broad range of subjects spanning the natural sciences, philosophy, linguistics, economics, politics, psychology, and the arts. Around this time (334 BC), Aristotle was the first to classify living things into the categories of "plants" and "animals". When it comes to his contribution to the cell theory, Aristotle was one of the earliest recorded scholars to believe in the spontaneous generation (the notion that life can arise from non-living matter).

1668 - Francesco Redi

aav741407 — 2024-02-07 13:50:06 UTC

Francesco Redi (1629-1697) was an Italian physician, naturalist, biologist, and poet. He was the first person to challenge and ultimately disprove the spontaneous generation. In 1668, Redi experimented with rotting meat in jars. The meat in an open container developed maggots, but the meat in the closed container did not. He found that maggots do not appear in meat if no contact with flies.

1748 - Lazzaro Spallanzani

aav741407 — 2024-02-07 13:58:31 UTC

Lazzaro Spallanzani (1729-1799) was an Italian Catholic priest, biologist, and physiologist who made important contributions to the spontaneous generation "debate". In 1748, the same year John Needham "proved" the spontaneous generation, Lazzaro Spallanzani disproved this experiment and theory. Spallanzani conducted a very similar experiment to Needham but boiled his broth longer. Spallanzani had no microbes show up in his sealed broth container.

1748 - John Needham

aav741407 — 2024-02-07 14:02:31 UTC

John Needham (1713-1781) was an English naturalist and Roman Catholic priest. Needham's experiments supported the spontaneous generation. In 1748, Needham conducted his famous experiment, beginning with boiled/sterilized meat broth. The broth was then divided into two containers, one that was sealed and another left unsealed. Within days the broth became cloudy which proved to Needham that life can arise from non-living matter (supporting the spontaneous generation).

1860 - Louis Pasteur

aav741407 — 2024-02-07 14:18:46 UTC

Louis Pasteur (1822-1895) was a French biologist who finally disproved the spontaneous generation. In 1860, Pasteur performed a similar experiment to both John Needham and Lazzaro Spallanzani but used a special type of flask (swan-neck flask) intended to deter contamination (from the outside environment). When the broth was not exposed to air, it remained sterile and free of microorganisms. Pasteur then exposed the broth to air/contaminated the broth and it quickly became cloudy.

1665 - Robert Hooke

aav741407 — 2024-02-07 14:28:50 UTC

Robert Hooke (1635-1703) was an English scientist who published the book "Micrographia" in 1665, which showed observations made under a microscope (notably illustrated cork images from a microscope). Hooke also named/coined the term "cells" (naming them after empty, room-like compartments... aka cells).

1590 - Hans & Zaccharias Janssen

aav741407 — 2024-02-08 01:15:49 UTC

Hans Janssen and Zacharias Janssen were Dutch eyeglass makers, who, in 1590 invented the first-ever compound microscope (an instrument/tool used to view magnified/"blown up" images of small specimens/substances). Their original microscope used two lenses and magnified the substance by ten times (10x).

1666/1667 - Antony van Leeuwenhoek

aav741407 — 2024-02-08 01:20:49 UTC

Antony van Leeuwenhoek (1632-1723) was a Dutch scientist (microbiologist and microscopist), often referred to as the "Father of Microbiology". Leeuwenhoek read Robert Hooke's book "Micrographia" about the microscope/observing things through the microscope. Throughout 1666/1667, Leeuwenhoek designed and used his own microscopes. Leeuwenhoek remained in often correspondence with the Royal Society writing letters in which he detailed/explained his work.

1673/1674 - Antony van Leeuwenhoek

aav741407 — 2024-02-08 01:27:11 UTC

Antony van Leeuwenhoek (1632–1723) is credited to be the creator of the microbial world (the world of organisms that are too small to be seen without using a microscope). Leeuwenhoek called the microorganisms that he found everywhere in vast numbers "very many little animalcules". The animalcules he was referring to can be more specifically referred to as bacteria (microscopic living organisms that have only one cell) and protozoa (similar to bacteria, but bigger with more complex structures).

1683 - Antony van Leeuwenhoek

aav741407 — 2024-02-08 01:50:17 UTC

In 1683, Antony van Leeuwenhoek (1632-1723) discovered bacteria by observing the plaque that he scraped from his teeth under a microscope. He noticed/noted "many very little living animalcules, very prettily a-moving".

1838 - Matthias Schleiden

aav741407 — 2024-02-08 01:58:00 UTC

Matthias Jakob Schleiden (1804-1881) was a German botanist (an expert/student of the scientific study of plants) and co-founder of cell theory, along with Theodor Schwann and Rudolf Virchow. In 1838 Schleiden defined the cell as the basic unit of plant structure, stating "All plants are made of cells".

1839 - Theodor Schwann

aav741407 — 2024-02-08 02:42:10 UTC

Theodor Schwann (1810-1882) was a German physiologist. Schwann's most significant contribution to biology would be his discovery/contribution to the cell theory. In 1839, just one year after Schleiden's claim, Theodor Schwann wrote, "All animals are made of cells".

1845 - Alexander Carl Henrich Braun

aav741407 — 2024-02-08 13:44:14 UTC

Alexander Carl Henrich Braun (1805-1877) was a German botanist (an expert/student of the scientific study of plants). In 1845, Henrich Braun wrote "The cell is the basic unit of life".

1858 - Rudolph Virchow

aav741407 — 2024-02-08 14:43:04 UTC

Rudolph Virchow (1821-1902) was a German physiologist, who, in 1858 made a statement that contributes to today's "cell theory". Virchow states, in short, "All cells come from pre-existing cells". This statement also disagrees with the controversial/incorrect spontaneous generation.