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318 BCE
Aristotle Describes Life with the Scala Naturae
Aristotle's ideas were based off of the Scala Naturae, "natural ladder", in which the entire world could be arranged in a single continuum. During the medieval period this became incorporated into the idea of the Great Chain of Being. -
162 BCE
Galen of Pergamon Describes the Human Body
Galen had great expertise in anatomy, surgery, and pharmacology and therapeutic methods. Galen was forced to dissect animals and treat wounded gladiators to learn more about human anatomy. -
Jun 2, 1546
The Germ Theory of Disease is Published
The germ theory of disease states that many diseases are caused by microorganisms. These small organisms invade humans, animals, and other living hosts. -
Lamarck Develops Hypothesis of Evolution by Means of Acquired Characteristics
Lamarckism is the idea that an organism can pass on characteristics that it has developed over the course of its lifetime to its off spring. However, this has been discarded since there is no chance that characteristics can be passed down through off spring. Traits, however can be passed down to off spring. -
The Voyage of the HMS Beagle
Darwin set sail on a ship called the HMS Beagle in 1831. He was the naturalist on the voyage. It was Darwin's job to observe and collect specimens of plants, animals, rocks, and fossils wherever the expedition went. -
Alfred Russel Wallace Published Ideas of Evolutionary Processes
Wallace discovered the concept of evolution by natural selection. On his first expedition Wallace realized that geographical barriers often marked species boundaries. On his second journey, he got a fever, had hallucinations, and said the theory of evolution by natural selection came to him. -
Louis Pasteur Refuses Spontaneous Generation
Pasteur invented the swan like necked flask to initiate an environment known to not grow microorganisms. In the end, microorganisms grew in the control but not in the experiment, which rejected spontaneous generation. -
The Origin of Species by Means of Natural Selection is Published
On the Origin of Species is a work of scientific literature by Charles Darwin which is considered to be the foundation of evolutionary biology. Darwin's book introduced the scientific theory that populations evolve over the course of generations through a process called natural selection. -
Gregor Mendel Publishes Works on Inheritance of Traits on Pea Plants
Trough Mendel's work on pea plants, he discovered the fundamental laws of inheritance. Mendel tracked the segregation of parental genes and their appearance in the off spring as dominant and recessive traits. -
The Challenger Oceanography Expedition Sails Around the World
Was a scientific exercise that made many discoveries to lay the foundation of oceanography. The expedition was named after the mother ship, HMS Challenger. -
Plasmodium Falciparum is Described as the Causative Agent of Malaria
Plasmodium Falciparum is a unicellular protozoan parasite of humans, and the deadliest of plasmodium that cause malaria. -
Hardy and Weinburg Independently Develop the Hardy-Weinburg Equation for Determining Allele Frequencies in Population
It is a mathematical equation which describes the distribution and expression of alleles in a population. It also expresses the conditions under which allele frequencies are expected to change. -
T. Hunt Morgan Discovers Sex-Linkage
Sex linkage is the phenotype expression of an allele that is dependent on the gender of the individual and is directly tied to the sex chromosome. -
Neil Bohr Develops the Bohr Model of Atom Structure
The model depicts an atom as a small, positively charge nucleus surrounded by electrons that travel in circular orbits around the nucleus. -
Frederick Griffith Describes the Process of Transformation
Griffith used two strains of Pneumococcus, a bacteria that infects mice. In his experiment, he noticed that bacteria were capable of transferring genetic information through a process called transformation. -
Theodosius Dobzhansky Publishes Genetics and the Origin of Species
Dobzhansky's book popularized the work of population genetics to other biologists, and influenced their appreciation for the genetic basis of evolution -
Beadle and Tatum Publish the 1 gene- 1 Enzyme Hypothesis
The theory stated that each gene directly produces a single enzyme. This in turn consequently affects an individual step in a metabolic pathway. -
Jacques Cousteau Develops Scuba
Cousteau and Gagnan co-invented a demand valve system that would supply divers with compressed air when they breathed in. They named it the Aqua-Lung. -
Avery, MacLeod, and McCarty Determine that DNA is the Molecule that Carries the Genetic Code
The Avery-MacLeod-McCarty experiment was an experimental demonstration, that DNA is the substance that causes bacterial information. -
Barbara McClintock Describes Transposons
McClintock discovered that genes could move from place to place on a chromosome when she experimented with breeding maize plants. -
The First Atomic Bomb is used in War
During World War II, an american B 29 bomber, dropped the worlds first deployed bomb over the Japanese city Hiroshima. -
Miler-Urey Experiments Published
Miller and Urey conducted an experiment claimed that several organic compounds could be formed spontaneously by simulating the conditions of the Earth's early atmosphere. -
Ensatina Described as a Ring Species
The Ensatina salamander has been widely cited as one of the two best examples of ring species in existence. A ring species is two populations, which do not interbreed, are living in the same region as a population that can interbreed. -
Rosalind Franklin Works with DNA and X-ray Crystallography and Develops "Image 51"
Image 5 was the nickname that was given to an x-ray diffraction image of DNA. -
Hershey-Chase Experiments are Published
Alfred Hershey and Martha Chase concluded a series of experiments to prove that DNA has the genetic material. Viruses were grown in one of two isotopic mediums. Viruses grown in radioactive sulfur had radioactive proteins. Viruses grown in radioactive phosphorus had radioactive DNA. It was demonstrated that DNA does have genetic material because the DNA transferred into the bacteria. -
Watson and Crick Propose the Double Helix model of DNA Structure
The discovery in 1953 of the double helix by Watson and Crick marked a milestone in the history of science and gave rise to modern molecular biology. -
Meselson and Stahl Work with DNA Replication
The Meselson-Stahl experiment was an experiment which supported the hypothesis that DNA replication was semi-conservative. -
Nirenberg Cracks the Genetic Code
Discovered the first "triplet" which was a sequence of three bases of DNA that codes for one of the 20 amino acids that serve as the building blocks of proteins. -
Endosymbiosis is Described by Lynn Magulis
The endosymbiotic theory, is an evolutionary theory of the origin of eukaryotic cells from prokaryotic organisms. -
Apollo 11 Landed on the Moon
The first manned aircraft landed on the moon. The first steps made by man were set by Neil Armstrong and Buzz Aldrin. They also returned the first specimens of the moon to earth. -
Theodosius Dobzhansky Publishes "Nothing in Science Makes Sense Except in the Light of Evolution"
The essay criticized anti-evolution creationism and exposing theistic evolution and offered arguments for evolution. -
Australopithicus Afarensis Nicknamed "Lucy" Fossil Discovered
"Lucy", a new species, is represented by several hundred fossils from east Africa. Lucy was one of the most important fossils ever discovered. The fossils were found in Ethiopia. -
The Sanger Technique is Developed
A method of DNA sequencing based on the selective incorporation of chain- terminating dideoxynucleotides by DNA plymerse during invitro DNA replication. -
Deep Sea Hydrotheramal Vents and Associated Life Around Them are Discovered
Hydrothermal vents are caused by a fissure in our planets surface from which geothermal heated water flows. They are commonly found near active volcano sites, ocean basins, and hot springs. -
Spliceosomes were Discovered and Described
Spliceosomes assemble on RNA polymerse II transcripts from which they excise RNA sequences call introns and splice together the flanking sequences called exons. -
Kary Mullis Develops Polymerase Chain Reaction
The polymerase chain reaction is a technique that allowed scientist to make millions of copies of a scarce sample of DNA and it revolutionized in biology. -
CRISPs/CAS 9 is Identified and Described
CRISPs/CAS 9 is a unique technology that enables geneticists and medical researchers to edit parts of the genome. -
Tommie Lee Andrews is Convicted of Rape
Serial rapist who became the first american to ever be convicted in a case that used DNA as evidence. -
Human Genome is Fully Sequenced
The human genome project was completed in April 14, 2003. They took blood samples from volunteers so they could analyze it. The blood samples came from a variety of people. By the end of the project they had like a manual of the entire genome system. -
"Reproductive Isolation as a Consequence of Adaptive Divergence in Drosophila Pseudoobscrura"
There were eight D. pseudoobsrura populations that were derived from a single population. Four starch-reared populations were designated Ist-IVth. The maltose-reared populations were designated Ima-IVma. The experiments were to see if the two populations could have induced ethological isolation. -
The Innocence Project is Founded
Non-profit legal organization that is committed to exonerating wrongly convicted people through use of DNA testing, and to reforming the criminal justice system to prevent future injustice. -
Dolly the Sheep is Cloned
The first mammal to have successfully been cloned from an adult cell. -
Sahelanthropus Tchadensis Fossil Discovered
Claimed as one of the most significant discoveries in human evolution. The fossil represents the oldest known human ancestor after the split from the chimpanzees. The remains are dated back 6-7 million years old. -
Homo Denisova Fossil Discovered
DNA was extracted from all four Denisovan fossils and determined that the species came from different individuals. Two dating back many years more than the other two indicating that the Denisovan people were around for a long time. -
Richard L Bible is Executed
Bible was found guilty when DNA evidence of blood smeared on his shirt matched the blood of the victim.