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Explore the historical development of the cell theory, from the Middle Ages to groundbreaking experiments in the 19th century by scientists like Robert Hooke, Antony van Leeuwenhoek, Louis Pasteur, and more. Discover the four parts of the cell theory and the contributions of key figures in biology.
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Development of the Cell Theory Biology 11
History • Middle ages - magnifying lenses • 1590 – first compound microscope • Required to view microscopic organisms • 1665 – Hooke discovered cells
Spontaneous Generation • Living organisms could suddenly arise from non-living materials • Believed until 19th century • Maggots on rotting meat • Frogs & salamanders appear in mud • Mushrooms on logs • Mice from a dirty shirt & wheat
Four Parts of the Cell Theory • All living organisms are composed of one or more cells. • Cells are the basic units of structure and function in all organisms. • All cells are derived from pre-existing cells. • In a multicellular organism, the activity of the entire organism depends on the total activity of its independent cells.
Asking Questions • 500 BC • Ancient Greece supports scholars • Ask questions about life & nature • Seek answers through observations & thought • Not experiments
Aristotle • Greek philosopher • 384 – 322 BC • 334 BC • Classified all living things • Plant or animal • Believed in spontaneous generation
Roger Bacon • English philosopher • 1214 – 1294 • 1268 • First wrote about eyeglasses
Magnifying Images • 1590 • Dutch eyeglass makers • Hans & Zaccharias Janssen • Invented first compound microscope • Used two lenses • Magnified 10x
King Charles II • English monarch • 1602 • Founded “Royal Society of London for the Promotion of Natural Knowledge” • Shared & debated knowledge • Used books, letters, meetings
Robert Hooke • English scientist • 1635 – 1703 • 1665 • Published book – Micrographia • Illustrated cork images from microscope • Coined term “cells” • Empty room-like compartments
Antony van Leeuwenhoek • Dutch scientist • 1632 – 1723 • 1666/1667 • Read Hooke’s book • Designed microscopes • Six times more magnifying power
Francesco Redi • Italian scientist • 1629 – 1697 • 1668 • Experiments disproved spontaneous generation • Maggots do not appear in meat if no contact with flies
van Leeuwenhoek (… again!) • Wrote letters to Royal Society • 1673/1674 • Described “animalcules” in water • Bacteria & protozoa • Hooke later confirmed findings
… van Leeuwenhoek (… again!) • 1683 • Examined plaque from teeth • “Many very little living animalcules, very prettily a-moving” • Discovered bacteria
John Needham • English naturalist & priest • 1713 – 1781 • 1748 • Experiments supported spontaneous generation
Lazzaro Spallanzani • Italian biologist • 1729 – 1799 • 1748 • Experiments disproved Needham & spontaneous generation • Boiled broth longer
1770’s • Microscope mechanical advancements • Sturdier & easier to use • Not as advanced or clear as van Leeuwenhoek’s
Jane Haldiman • English science writer • 1809 • Developed textbooks about science • Used terms “cell”, “cellular system”, “cell tissue”
Robert Brown • Scottish botanist • 1773 – 1858 • 1831 • All cells contain a nucleus
Matthias Jacob Schleiden • German botanist • 1804 – 1881 • 1838 • Wrote “All plants are made of cells”
Theodor Schwann • German physiologist • 1810 – 1882 • 1839 • Wrote “All animals are made of cells”
Alexander Carl Henrich Braun • German botanist • 1805 – 1877 • 1845 • Wrote “The cell is the basic unit of life”
Jugo von Mohl • German biologist • 1805 – 1872 • 1846/1847 • Described protoplasm (cytoplasm) and cell membrane
William Henry Perkin • English chemistry student • 1838 – 1907 • 1856 • Developed a purple dye • Used to stain slide specimens
Rudolph Virchow • German physiologist • 1821 – 1902 • 1858 • Stated (in short) … “All cells come from pre-existing cells” • Disagree with spontaneous generation
Louis Pasteur • French biologist • 1822 – 1895 • 1860 • Finally disproved spontaneous generation • Living organisms DO NOT come from non-living matter • Prize from Paris Academy of Sciences
Schleiden Plants are made up of cells Schwann Animals are made up of cells Virchow All cells come from other cells Indirect Credit: Hooke Discovery of cells van Leeuwenhoek Microscope improvements Cell Theory Scientists