* ?? – Jan Baptist van Helmont performed his famous tree plant experiment in which he shows that the substance of a plant derives from water, a forerunner of the discovery of photosynthesis.
* 1628 – William Harvey published An Anatomical Exercise on the Motion of the Heart and Blood in Animals
* 1651 – William Harvey concluded that all animals, including mammals, develop from eggs, and spontaneous generation of any animal from mud or excrement was an impossibility.
* 1665 – Robert Hooke saw cells in cork using a microscope.
* In 1661, 1664 and 1665, the blood cells were discerned by Marcello Malpighi. In 1678, the red blood corpuscles was described by Jan Swammerdam of Amsterdam, a Dutch naturalist and physician. The first complete account of the red cells was made by Anthony van Leeuwenhoek of Delft in the last quarter of the 17th century.
* 1668 – Francesco Redi disproved spontaneous generation by showing that fly maggots only appear on pieces of meat in jars if the jars are open to the air. Jars covered with cheesecloth contained no flies.
* 1672 – Marcello Malpighi published the first description of chick development, including the formation of muscle somites, circulation, and nervous system.
* 1676 – Anton van Leeuwenhoek observed protozoa and calls them animalcules.
* 1677 – Anton van Leeuwenhoek observed spermatozoa.
* 1683 – Anton van Leeuwenhoek observed bacteria.  Leeuwenhoek's discoveries renew the question of spontaneous generation in microorganisms.