William of Occam decided that a hypothesis was most probable to be true if it was based on the least amount of assumptions possible, was simple, and consisted with data.
Microscopist Anthony van Leeuwenhoek made this discovery, adding a whole new dimension to biology.
in 1758, Carolus Linnaeus first developed the specific, accurate system of binomial nomenclature to describe animals.
William Smith made the connection between different geological strata and fossils specific to them. He formed a method to approximating the age of fossils.
R. Dutrochet (1824), H. von Mohl (1831), and M.J. Schleiden and T. Schwann (1839) helped form the idea that all tissues in both plants and animals were made up of cells (similar units).
F. Wohler was the first to artificially synthesize an organic compound: urea.
W. Hofmeister formed the first concept of chromosomes in pollen cells.
Charles Darwin published a paper emphasizing how natural selection was a crucial part of evolution.
T. Schjelderup-Ebbe observed the complex hierarchies in birds.
Crick, Francis H.C., James D. Watson, and Maurice H.F. Wilkins first hypothesized the helix structure of DNA strands.