Ancient theories[ edit ] Aristotle's model of transmission of movements from parents to child, and of form from the father. The model is not fully symmetric. Hippocrates' theory possibly based on the teachings of Anaxagoras was similar to Darwin's later ideas on pangenesisinvolving heredity material that collects from throughout the body.
Cell Theory and Cell Structure Photo by: These simple and powerful statements form the basis of the cell theory, first formulated by a group of European biologists in the mids. So fundamental are these ideas to biology that it is easy to forget they were not always thought to be true.
Hooke first described cells in Early Observations The invention of the microscope allowed the first view of cells. English physicist and microscopist Robert Hooke — first described cells in He made thin slices of cork and likened the boxy partitions he observed to the cells small rooms in a monastery.
The open spaces Hooke observed were empty, but he and others suggested these spaces might be used for fluid transport in living plants.
He did not propose, and gave no indication that he believed, that these structures represented the basic unit of living organisms. Marcello Malpighi —and Hooke's colleague, Nehemiah Grew —made detailed studies of plant cells and established the presence of cellular structures throughout the plant body.
Grew likened the cellular spaces to the gas bubbles in rising bread and suggested they may have formed through a similar process. The presence of cells in animal tissue was demonstrated later than in plants because the thin sections needed for viewing under the microscope are more difficult to prepare for animal tissues.
The prevalent view of Hooke's contemporaries was that animals were composed of several types of fibers, the various properties of which accounted for the differences among tissues. At the time, virtually all biologists were convinced that organisms were composed of some type of fundamental unit, and it was these "atomistic" preconceptions that drove them to look for such units.
While improvements in microscopy made their observations better, it was the underlying belief that there was some fundamental substructure that made the microscope the instrument of choice in the study of life.
In the Dutch microscopist Antony van Leeuwenhoek — published his observations of single-cell organisms, or "little animalcules" as he called them. It is likely that Leeuwenhoek was the first person to observe a red blood cell and a sperm cell.
Leeuwenhoek made numerous and detailed observations on his microorganisms, but more than one hundred years passed before a connection was made between the obviously cellular structure of these creatures and the existence of cells in animals or plants. The Development of the Cell Theory In Frenchman Henri Milne-Edwards suggested that the basic structure of all animal tissues was an array of "globules," though his insistence on uniform size for these globules puts into question the accuracy of his observations.
Henri Dutrochet — made the connection between plant cells and animal cells explicit, and he proposed that the cell was not just a structural but also a physiological unit: Raspail was the first to state one of the two major tenets of cell theory: Omnis cellula e cellula, which means "Every cell is derived from another cell.
Raspail was also the founder of cell biochemistry, making experiments on the chemical composition of the cell and their response to changing chemical environments. In Barthelemy Dumortier — of France described "binary fission" cell division in plants.
He observed the formation of a mid-line partition between the original cell and the new cell, which, Dumortier noted, "seems to us to provide a perfectly clear explanation of the origin and development of cells, which has hitherto remained unexplained" Harrisp.
The discovery of cell division is usually attributed to Hugo von Mohl —but Dumortier proceeded him in this regard.
Von Mohl did coin the word "protoplasm" for the material contained in the cell. The first unequivocal description of the cell nucleus was made by a Czech, Franz Bauer, in and was given its name in by Robert Brown — of Scotland, who is best remembered for discovering the random "Brownian" motion of molecules.
The first accurate description of the nucleolus was made in In the history of DNA, the Eugenics movement is a notably dark chapter, which highlights the lack of understanding regarding the new discovery at the time.
The term 'eugenics' was first used around to refer to the "science" of heredity and good breeding. Cope looked for, and thought he found, patterns of linear progression in the fossil record. Inheritance of acquired characteristics was part of Haeckel's recapitulation theory of evolution, which held that the embryological development of an organism repeats its evolutionary history.
The most influential early theories of heredity were that of Hippocrates and Aristotle. Hippocrates' theory (possibly based on the teachings of Anaxagoras) was similar to Darwin's later ideas on pangenesis, involving heredity material that collects from throughout the body.
Evolution Theory Timeline Timeline Description: Evolution, which is the change of characteristics of different populations over time, is the theory used to explain the massive diversity experienced on Earth.
These changes occur with small mutations in genes, which are then passed onto offspring. The history of genetics dates from the classical era with contributions by Hippocrates, Aristotle and plombier-nemours.com biology began with the work of the Augustinian friar Gregor Johann Mendel.
His work on pea plants, published in ,what is now Mendelian plombier-nemours.com theories of heredity suggest in the centuries before and for several . Jan 19, · This strange theory has a relatively normal name, but rest assured, the concept is far from it. Hans Hörbiger (pictured above), an Austrian engineer and inventor received a vision in which told him that ice was the substance of all basic substances and had created the ice moons, ice planets, and a “global ether”.