August Weismann was a German evolutionary biologist. His main contribution was the germ plasm theory, according to which (in a multicellular organism) inheritance only takes place by means of the germ cells
Rudolf Virchow was also a public health activist, social reformer, politician, and anthropologist. He explain using cell theory, the effects of disease in the organs and tissues of the body. Virchow’s greatest accomplishment was his observation that a whole organism does not get sick—only certain cells or groups of cells
Theodor Schwann was a German physiologist.His many contributions to biology include the development of cell theory, the discovery of Schwann cells in the peripheral nervous system, the discovery and study of pepsin, the discovery of the organic nature of yeast, and the invention of the term metabolism. in 1837 he had viewed and stated that new plant cells formed from the nuclei of old plant cells) in 1837, the conversation turned on the nuclei of plants and animal cells.
Antony van Leeuwenhoek was an unlikely scientist. He was known as the "father of microbiology. A tradesman of Delft, Holland, he came from a family of tradesmen, had no fortune, received no higher education or university degrees. Leeuwenhoek is known to have made over 500 "microscopes," of which fewer than ten have survived to the present day. Anton Leeuwenhoek discovered blood cells and microscopic animals such as nematodes and rotifers.
Van Leeuwenhoek's main discoveries are:
the infusoria (protists in modern zoological classification), in 1674
the bacteria, (e.g. large Selenomonads from the human mouth), in 1676
the spermatozoa in 1677. Van Leeuwenhoek had troubles with Dutch theologists about his practice.
the banded pattern of muscular fibers, in 1682.
Robert Hooke is one of the most neglected natural philosophers of all time.The inventor of, amongst other things, the iris diaphragm in cameras, the universal joint used in motor vehicles, the balance wheel in a watch, the originator of the word 'cell' in biology, he was Surveyor of the City of London after the Great Fire of 1666, architect, experimenter, and also worked in astronomy.While his research and findings were often overshadowed by those of his rival Sir Isaac Newton, he was one of the most important scientists of the 17th century. In 1665, the English physicist Robert Hooke looked at a sliver of cork through a microscope lens and noticed some "pores" or "cells" in it. Robert Hooke believed the cells had served as containers for the "noble juices" or "fibrous threads" of the once-living cork tree. He thought these cells existed only in plants, since he and his scientific contemporaries had observed the structures only in plant material.Robert Hooke, the English father of microscopy, re-confirmed Antony van Leeuwenhoek's discoveries of the existence of tiny living organisms found under the microscope in a drop of water
Hans and Zacharias Janssen were the inventors of the first optical telescope and the single lens optical compound microscope. Both Hans and Zacharias were dutch spectacle-makers in middle-burg, Netherlands. Around 1590, Hans and Zacharias Janssen created the first compound microscope. This microscope was capable of taking a closer look at different objects
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