Lead Up to the Proposal of the Cell Theory

Improvements to the Compound Microscope:For a lens to be effective, it needs to do two things Give an enlarged view of the object Make the detail appear clear, giving a precise (not fuzzy) outline to the part of the object being viewed Ability to enlarge an image is termed classificationAbility to show fine detail, distinguishing two very close objects as separate images is termed resolution During the 17th the hand held tube designed by the Janssens was mounted onto a stand The design we know today began to take shape Robert Hooke Robert Hooke produced the first recorded publication to describe observations of living tissue using a microscope Coined the term 'Cell' Hooke's findings were respected, but not universally accepted by scientists at the time Hooke's compound microscope was progressive for its time Microscope used a fine adjustment knob to move the tube holding the lenses up and down Microscope also has a light source to illuminate the specimen Robert Brown Discovered the cell nucleus Had no idea at the time of the importance of the nucleus or its function in cells Travelled to Australia in 1801 and identified many genera of Australian plants Microscopes as Valid Scientific Instruments Added benefit of powerful light sources Precise focusing screws Observations made were accepted as valid scientific evidence Shortly after this time the cell theory was proposed Significance of Technological Advances Without technological advances the development of the cell theory would not have happened The main areas of advancement have been in the invention and further development in the design of the microscope Microscope enabled us to see cells, opening doors for the development of the cell theory The staining of cells (specimen preparation) enabled the division of the nucleus in cell division to be observed Technological advances go hand in hand with the development of the cell theory Evidence to Support the Cell Theory Robert Hooke's observation of cork cells, and Leeuwenhoek's observation of many types of unicellular cells proving that living things are made up of cells Flemming's observation of cell division - mitosis - proved that cells come from pre-existing cells