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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 - PowerPoint PPT Presentation
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Development of the Cell Theory
Biology 11
History
Middle ages - magnifying lenses
1590 – first compound microscopeRequired 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 meatFrogs & salamanders appear in mudMushrooms on logsMice from a dirty shirt & wheat
Four Parts of the Cell Theory
1. All living organisms are composed of one or more cells.
2. Cells are the basic units of structure and function in all organisms.
3. All cells are derived from pre-existing cells.
4. In a multicellular organism, the activity of the entire organism depends on the total activity of its independent cells.
Asking Questions
500 BCAncient Greece supports scholars
Ask questions about life & natureSeek answers through observations & thought
Not experiments
Aristotle
Greek philosopher 384 – 322 BC
334 BCClassified all living things
Plant or animal
Believed in spontaneous generation
Roger Bacon
English philosopher1214 – 1294
1268First wrote about eyeglasses
Magnifying Images
1590Dutch eyeglass makers
Hans & Zaccharias Janssen
Invented first compound microscopeUsed two lensesMagnified 10x
King Charles II
English monarch
1602Founded “Royal Society of London for the Promotion of Natural Knowledge”Shared & debated knowledge
Used books, letters, meetings
Robert Hooke
English scientist1635 – 1703
1665Published book – Micrographia
Illustrated cork images from microscope
Coined term “cells”Empty room-like compartments
Antony van Leeuwenhoek
Dutch scientist1632 – 1723
1666/1667Read Hooke’s bookDesigned microscopes
Six times more magnifying power
Francesco Redi
Italian scientist1629 – 1697
1668Experiments disproved spontaneous generation
Maggots do not appear in meat if no contact with flies
Redi’s Experiment
van Leeuwenhoek (… again!)
Wrote letters to Royal Society
1673/1674 Described “animalcules” in water
Bacteria & protozoa
Hooke later confirmed findings
… van Leeuwenhoek (… again!)
1683Examined plaque from teeth
“Many very little living animalcules, very prettily a-moving”Discovered bacteria
John Needham
English naturalist & priest1713 – 1781
1748Experiments supported spontaneous generation
John Needham’s Experiment
Lazzaro Spallanzani
Italian biologist1729 – 1799
1748Experiments 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
1809Developed textbooks about scienceUsed terms “cell”, “cellular system”, “cell tissue”
Robert Brown
Scottish botanist1773 – 1858
1831All cells contain a nucleus
Matthias Jacob Schleiden
German botanist1804 – 1881
1838Wrote “All plants are made of cells”
Theodor Schwann
German physiologist
1810 – 1882
1839Wrote “All animals are made of cells”
Alexander Carl Henrich Braun
German botanist1805 – 1877
1845Wrote “The cell is the basic unit of life”
Jugo von Mohl
German biologist1805 – 1872
1846/1847Described protoplasm (cytoplasm) and cell membrane
William Henry Perkin
English chemistry student1838 – 1907
1856Developed a purple dye
Used to stain slide specimens
Rudolph Virchow
German physiologist1821 – 1902
1858Stated (in short) … “All cells come from pre-existing cells”
Disagree with spontaneous generation
Louis Pasteur
French biologist1822 – 1895
1860Finally disproved spontaneous generation
Living organisms DO NOT come from non-living matterPrize from Paris Academy of Sciences
Louis Pasteur’s Experiment
Cell Theory Scientists
1. SchleidenPlants are made up of cells
2. SchwannAnimals are made up of cells
3. VirchowAll cells come from other cells
Indirect Credit:Hooke
Discovery of cells
van Leeuwenhoek
Microscope improvements