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347 BCE
Aristotle describes like with the Scala Naturae
This is a strict, religious hierarchical structure of all matter and life that was believed to have been decreed by God. The chain starts from God and goes downward to angels, then demons, stars, moon, kings, princes, nobles, commoners, wild animals, domesticated animals, trees, other plants, precious stones, precious metals, and other minerals. This was all developed during the Middle Ages. -
Aug 14, 1543
Galen of Pergamon describes the human body
He printed descriptions and illustrations of human dissections and were published in the seminal work De humani corporis fabrica by Andreas Vesalius where Galen's physiological theory was accommodated to these new observation. -
Jun 22, 1546
The Germ Theory of Disease is published
This theory states that some diseases are caused by microorganisms that invade humans and animals and cause disease by their reproduction and growth within their hosts. -
Lamarck develops hypothesis of evolution by means of acquired characteristics
Inheritance of acquired characteristics is a hypothesis that states that physiological changes acquired over time over the life of an organism could be transmitted to its offspring. -
The voyage of the HMS beagle
Being the third volume of The Narrative of the Voyages of H.M. Ships Adventure and Beagle, this one is written by its commander, Darwin, about his journey from Plymouth Sound. This trip lasted almost five years when it was only originally planned to last two. This volume is his scientific field journal about geology, biology and anthropology. -
Gregor Mendel publishes works on inheritance of traits in pea plants
He discovered the fundamental laws of inheritance through his work on pea plants. He discovered that genes come in pair and are inherited as distinct units, one from each parent. -
Louis Pasteur refutes spontaneous generation
Pasteur invented the swan-necked flask to imitate an environment known to not grow microorganisms. In the end, microorganisms grew in the control but not in the experimental, which rejected spontaneous generation. -
Wallace published ideas of evolutionary processes
Although his ideas were previously studied for decades before he came up with the idea, Darwin and Wallace developed a similar theory that nature selects some individuals to be better suited for survival, in the end producing different body parts. -
The origin of species by means of natural selection is published
This is considered to be the foundation of evolutionary biology, it is written by Charles Darwin. It introduces the scientific theory and natural selection -
The Challenger Oceanography Expedition sails around the world
This was a scientific exercise that made many discoveries to lay the foundation of oceanography. The Challenger discovered over 4,000 previously unknown species as well as other historical findings. 19 years after the completion of its journey, findings were still being published into 50 different volumes with other 25,000 pages in length. -
Plasmodium falciparum is described as the causative agent of malaria
PF is a protozoan parasite that causes malaria in humans. It is first transmitted by the female Anopheles mosquito. This is specific species causes the most dangerous form of this disease. -
Hardy and Weinberg independently develop the Hardy-Weinberg equation for determining allele frequencies in populations
This is a mathematical equation describing the distribution and expression of alleles in a population, and it expresses the conditions under which allele frequencies are expected to change. -
T. Hunt Morgan discovers sex-linkage
After looking into a microscope of a male fruit fly, instead of the fruit fly having the normal big, red eyes, it had white eyes. Morgan was curious as to how the traits are inherited and distributed in developing organisms. In his discovery, he found that the white-eye trait followed patterns of sex chromosome inheritance. -
Neils Bohr develops the Bohr model of atom structure
This model depicts the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus. This is a similar structure to the solar system. -
Frederick Griffith describes the process of transformation
This was the first experiment suggesting that bacteria are capable of transferring genetic information through a process known as transformation. -
Theodosius Dobzhansky publishes Genetics and the Origin of Species
This book popularized the work of population genetics to other biologists, and influenced their appreciation for the genetic basis of evolution. He applied the work of Sewall Wright to the study of natural populations, allowing him to address evolutionary problems in a novel way. -
Beadle and Tatum publish the 1 gene-1 enzyme hypothesis
This is the idea that genes act through the production of enzymes that in turn affects a single step in a metabolic pathway. -
Jacques Cousteau develops SCUBA
Known as "the father of scuba diving" he played a huge role in the development in scuba diving while also raising awareness to marine life and to the things that endanger it -
Ernst Mayr develops the Biological Species Concept espousing
This concept explains how that a species consists of populations of organisms that can reproduce with one another and that are reproductively isolated from other populations. -
Avery, MacLeod and McCarty determine that DNA is the molecule that carries the genetic code
Together, they worked with the bacterium that causes pneumonia, Streptococcus pneumoniae. In test tubes, they used detergent to separate out the different components and they destroyed them to identify which one was the transforming principle. -
Barbara McClintock describes transposons
Between the 1940's-50's, she discovered transposition and use it to demonstrate that genes are responsible for turning physical characteristics on and off. -
Miller-Urey experiments published
Chemical experiment that tested the chemical origin of life. This experiment confirmed another hypothesis thought out by Oparin and Haldane "putative conditions on the primitive Earth favored chemical reactions that synthesized more complex organic compounds from simpler inorganic precursors." -
Ensatina described as a ring series
Populations moved south and evolved into different subspecies w/ new colors, patterns, and adaptions to live in different environments -
Rosalind Franklin works with DNA and X-ray crystallography and develops "Image 51"
Image 51 is an xray diffraction image taken by Rosalind Franklin and Raymond Gosling revealing the double helix structure of DNA. -
Hershey-Chase experiments are published
A series of experiments done by Alfred Hershey and Martha Chase that helped to verify that DNA is in fact genetic material. -
Watson and Crick propose the double helix model of DNA structure
According to their findings, DNA replicated itself by separating into individual strands, each of which became the template for a new double helix. -
Meselson and Stahl work with DNA replication
They decided that the best way to tag the parent DNA would be to change one of the atoms in the parent DNA molecule. They decided to use an isotope of nitrogen to distinguish between parent and newly copied DNA. -
Nirenberg cracks the genetic code
The genetic code was cracked when Nirenberg and Matthaei performed their scientific experiment by using nucleic acid homo polymers to translate specific amino acids/ -
Endosymbiosis is described by Lynn Margulis
Although this theory was first articulated in 1910 by Konstantin Mereschkowski, it was later advanced and substantiated with microbiological evidence by Lynn Margulis in 1967. This is an evolutionary theory of the origin of eukaryotic cells from prokaryotic organisms. -
Apollo 11 lands on the moon
First spaceflight that landed humans on the moon. The lunar module was called Eagle and on it was mission commander Neil Armstrong and pilot Buzz Aldrin. -
Theodosius Dobzhansky plublishes "Nothing in science makes sense except in the light of evolution"
The evolutionary biologist wrote this essay critisising anit-evolution creationism and promoting theistic evolution. -
"Lucy" fossil discovered
Discovered by Donald Johanson and a graduate student named Tom Gray while looking for fossils in Ethiopia's Afar Triangle, they came across some remains of an unknown ape-like specie. Later classified as a 3.2 million year old australopithecus afarensis, nicknamed Lucy. -
Deep sea hydrothermal vents and associated life around them are discovered
While exploring the Galapagos Rift along the mid-ocean ridge, scientists noticed a series of temperature spikes in their data. This got them questioning on how deep-ocean temperatures could change so drastically in such a short distance. The cause for this is deep sea hydrothermal vents. Adding to their discovery was a unique ecosystem that existed around the vents, -
The Sanger Technique is developed
This method of DNA sequencing first commercialized by Applied Biosystems based on the selective incorporation of chain-terminating dideoxynucleotides by DNA polymerse during in vitro DNA replication. This method was developed by Frederick Sanger. -
Spliceosomes were discovered and described
The work by Sharp and Roberts labs revealed that genes of higher organisms are "split". A spliceosome is a large and complex molecular machine found in primarily within the splicing speckles of the cell nucleus of eukaryotic cells. -
Kary Mullis develops Polymerase Chain Reaction
One night, while he was driving home with his girlfriend, he had an idea to use a pair of primers to bracket the desired DNA sequence and to copy it using DNA polymerase. This technique would allow rapid amplification of a small strand of DNA and become a standard procedure in molecular biology labs. -
Richard L. Bible is execute
9-year old Jennifer Wilson was riding her bike to her Flagstaff ranch and never arrived. Three weeks later, her naked body was found hidden under a tree, covered in branches with her hands tied behind her back. Blood smeared on a shirt and worn by Bible at his arrest was tested and found to be the blood of Jennifer. -
CRISPr/CAS 9 is identified and described
CRISPr are segments of prokaryotic DNA containing short repetitions of base sequences. The CRISPR/Cas system is a prokaryotic immune system that confers resistance to foreign genetic elements such as those present within plasmids and phages. -
Tommie Lee Andrews is convicted of rape
24-year old Andrews broke into a 27-year old woman's house and raped and stabbed her, he testified that he had never left his house the night the woman was raped. An expert in genetics analysis had testified that the DNA "fingerprint" of Andrews' blood matched that of the rapist's semen. -
Human genome finally sequenced
A T C G were found to be sequenced in the human genome -
"Reproductive isolation as a consequence of adaptive divergence in Drosophila pseudoobscrura" pusblished
This tells us that in the "attempt to learn the process of the development of reproductive isolation, eight populations of Drosophila pseudoobscura were studied." These eight populations were derived from the Bryce Canyon in Utah. These populations were used for this experiment. -
The Innocence Project is founded
This project is a non-profit legal organization that is committed to exonerating wrongly convicted people through the use of DNA testing and to reform the criminal justice system to prevent future injustice. This project was founded by Barry Schneck and Peter Neufeld. -
Dolly the sheep is cloned
Dolly was the first mammal cloned from an adult somatic cell, using the process of nuclear transfer. Cloned by Ian Wilmut and his other colleagues at the Roslin Institute. She had three mothers. One provided the egg; another the DNA, and the third carried the cloned embryo to term. -
Sahelanthropus tchadensis fossil discovered
Sahelanthropus tchadensis are one of the oldest known species. Even though they lived between 6 to 7 million years ago, we are still learning new things about them everyday -
Homo denisova fossil discovered
Scientists announced the discovery of a finger bone fragment of a juvenile female who lived about 41,000 years ago. It was found in Siberia in the remote Denisova Cave in the Altai Mountains. This cave also inhabited Neanderthals and modern human.
