Charles Darwin–12 February 1809 – 19 April 1882– was an English naturalist and arguably the founder of modern biology. Under immense pressure from his family to pursue a career in medecine, Charles fled upon the HMS Beagle on a five year voyage around the world. Originally interested in geology, Charles Darwin was primarily focused on how the landscape of Earth had evolved, not necessarily the species that inhabited it. On his famous expedition to the Galapagos islands far off the coast of Ecuador, Charles Darwin was struck by ostensible patterns not in the landscape, but in the animals on the islands. He noticed extremely similar variations or certain animals, especially finches, and hypothesized that such differences in in outwardly similar species had to be due to a form of common ancestry. His work coalesced into a theory that over thousands of generations, animals that are more properly suited to their environments have a better chance of reproducing and delivering their traits to their offspring. Over these generations, Darwin argued, favorable traits will be preserved in place of unfavorable ones. This viewpoint differed with other evolutionary theorists who believed in the Lamarckian theory that traits acquired in the lifetime of an animal are passed down to their offspring. The classic fallacy was that an animal that grew large and muscular would mass that size straight to its offspring. In his work, On The Origin of Species, Darwin solidified a theory in which change was gradual and dependent on genetics which remained unchanged over the course of an animals life, regardless of how its physique changed over time. This principal of natural selection producing gradual change provides the basis for the existence of all biological functions and the development of life on earth. It is often said that nothing in Biology makes sense unless put into the context of evolution and natural selection. These two terms are the be all and end all of the genetics that are responsible for the human race
Prior to the scientific advances made in the nineteenth century, all thought about the structure matter was purely speculative. Atomic theory came with the acceptance of elements as the pure substances that composed matter. At first, anyone’s guess was as good as another’s as to how elements themselves were composed. Some basic assumptions were made by John Dalton, an English chemist who died in 1844, as to the existence of atoms as the basic unit of all matter. From there, more assumptions were made that elements themselves must be neutrally charged. Such a basic hypothesis was proved in laboratories when pure substances were measured as exhibiting no charge and not showing attraction to certain magnets. In 1856 a British Chemist named J.J. Thomson discovered the presence of negatively charged parts of atoms when he hypothesized that there were actually smaller particles in existence that were responsible for the composition of atoms. He discovered electrons by submitting atoms to magnetic waves, and testing to see if there was any interaction via a paddel that would spin if the magnetic field was disrupted by a negative charge. When he was met with a positive result, it was concluded that electrons existed within atoms, and that there must be an equivalent group of positively charged subatomic particles to maintain elemental neutrality. This discovery laid the foundation for the formal discovery of protons, and neutrons, as well as the nucleus centered theory of atoms
While precursors to the Periodic Table existed prior to its official creation by Dmitri Mendeleev in 1869, the Russian Chemist is credited with its discovery. The Periodic Table was on one hand the culmination of centuries of research in rudimentary chemistry and alchemy, and on the other hand, the birth of modern science as the world knows it. The Periodic table was a breakthrough because of the predictive powers that it provided scientists with as the twentieth century approached. With the Second Industrial Revolution that thrived upon petroleum and engineering of chemicals, the Periodic Table organized known chemistry in a way that allowed scientists to group elements by common properties and predict the existence of other elements based off of reoccurring trends. The trends that were uncovered with the categorizing of elements based off of mass and proton number provided an unlimited amount of new research to be conducted in order to explain the trends which were on the one hand conspicuous to chemists, but on the other hand mysterious in their origins. Mendeleev organized elements based on their mass– a system which was later revised, though not subject to revolutionary change.