Biology Cells

Cell Biology as a science began within the pro­gressive evolution of the Cell Doctrine.

Briefly summarized, this doctrine states that cells are the fundamental units of both structure and function in all living things; that all forms of life (animal, plant, and microbial) are composed of cells and their secretions; and that cells arise only from preexisting cells, each cell haying a life of its own in addition to its integrated role in multi-cellular organisms.

This statement seems both elementary and obvious s to any student with some background in the biological sciences.

Nevertheless, it took several centuries for this concept to be developed and accepted. The very existence of cells was not even suspected until the sev­enteenth century, because most cells are too small to be discerned with the naked eye, and because instru­ments for significantly magnifying small objects did not exist.

However, with the introduction of the first crude light microscopes, investigators began to exam­ine small organisms, tissues cut from plants or re­moved from animals, and the “animalcules” in pond water. The invention of the microscope and its gradual improvement went hand-in-hand with the develop­ment of the cell doctrine. It finally became apparent that a fundamental similarity existed in the structural organization of all the living things studied.

What follows is a brief description of a few of the historical highlights i-hat culminated in the cell doc­trine. Although a great many individuals made contri­butions of varying significance to the development of this concept, the works of a certain small number of people stand out as milestones.

Printed in 1558 were the results of Conrad Gesner’s (Swiss, 1516-1565) studies on the structure of a group of protists called foraminifera. What is especially sig­nificant about this work is that Gesner’s sketches in­cluded so much detail that they could only have been made if he had used some form of magnifying lens....