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330 BCE
Aristotle describes life with Scala Naturae
Aristotle stated that “scala naturae”, or natural scale, was meant to represent the hierarchical classification of various forms of life. The idea is that the natural world could be arranged in one continuum. This led to the idea of the Great Chain of Being. -
160 BCE
Galen of Pergamon describes the human body
Galen was a Greek physician, surgeon, and philosopher in the Roman Empire. He accomplished many things in the medical field. Galen influenced the development of anatomy, physiology, pathology, pharmacology, and neurology, as well as philosophy. -
Lamarck developed hypothesis of evolution by means of acquired characteristics
The theory of the inheritance of acquired characteristics states that changes that organisms go through to adapt can be inherited by the offspring. According to Lamarck the characteristics of changes happen beceause of use and disuse of characteristics, environmental influences, disease, and mutilation. -
The Voyage of the HMS Beagle
Charles Darwin was invited on the HMS Beagle to be the ship's naturalist for a trip around the world. they traveled the coast of South America, He made many careful observations on animals, plants, and geology, and collected thousands of specimens. https://www.amnh.org/exhibitions/darwin/a-trip-around-the-world/ -
Alfred Russel Wallace published ideas of evolutionary processes
Wallace was one of the leading evolutionary thinkers of the 19th century and contributed to the development of evolutionary theory, he was a co-discoverer of natural selection. Darwin and Wallace had similar ideas on evolution. https://www.npr.org/2013/04/30/177781424/he-helped-discover-evolution-and-then-became-extinct -
The Origin of species by means of Natural Selection is published
Darwin was the son of a successful English doctor, he had a great interest in botany and natural sciences. Darwin created a reputation as a field researcher and scientific writer by traveling South America for five years as a botanist on the HMS Beagle. His book was the base for modern botany, cellular biology, and genetics. https://www.history.com/this-day-in-history/origin-of-species-is-published -
The Germ Theory of Disease is published
The Germ Theory states that certain diseases are caused by the invasion of the body by microorganisms. Louis Pasteur stated this theory in the 1860s and then Robert Koch provided the scientific proof for germ theory. -
Louis Pasteur refutes spontaneous generation
Louis Pasteur designed an experiment to test whether sterile nutrient broth could spontaneously generate microbial life. He set up two experiments, Pasteur added nutrient broth to flasks, he then bent the necks of the flasks into S shapes, and then boiled the broth to kill any existing microbes. -
Gregor Mendel publishes works on inheritance of traits in pea plants
Through his work on pea plants, Mendel is responsible for the fundamental laws of inheritance. He found that genes come in pairs and are inherited as distinct units, one coming from each parent. He tracked the segregation of parental genes and their appearance in the offspring as dominant or recessive traits. He discovered a mathematical way of predicting inheritance from one offspring to the next. -
The Challenger Oceanography Expedition sails around the world
the Challenger expedition went from 1872 to 1876. This was the reason for many discoveries from oceanography. It was described as “the greatest advance in the knowledge of our planet" since the celebrated discoveries of the fifteenth and sixteenth centuries. They traveled nearly 70,000 nautical miles. -
Hardy and Weinberg independently develop the Hardy-Weinberg equation for determining allele frequencies in populations
Godfrey Hardy was an English mathematician, and Wilhelm Weinberg was a German physician. The Hardy-Weinberg equilibrium is a mathematical equation describing the distribution and expression of alleles in a population. Mathematically, since p + q 1 , (p + q) 2 must also equal 1 -
T. Hunt Morgan discovers sex-linkage
Through many research and observation in flies, Morgan Concluded that the white eye trait followed patterns of sex chromosome inheritance. His experiment confirmed the chromosome theory. Morgan was the first to definitively link the inheritance of a specific trait with a particular chromosome. https://www.nature.com/scitable/topicpage/thomas-hunt-morgan-and-sex-linkage-452 -
Neils Bohr develops the Bohr model of atom structure
The Bohr model shows the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbit around. The model demonstrates how electrons can have stable orbits around the nucleus. -
Frederick Griffith describes the process of transformation
In this experiment conducted by Frederick Griffith, he combined heat-killed S with live R and injected the combination into mice. The mice did not survive. The dead mice tissues were found to contain live bacteria with smooth coats like S. This bacteria was subsequently able to kill other mice, he concluded that something in the heat-killed S bacteria “transformed.” www.mun.ca/biology.org -
Theodosius Dobzhansky publishes Genetics and the Origin of Species
Biologist Theodosius Dobzhansky uses the theories of mutation, natural selection, and speciation to explain habits of populations and the resulting effects on their genetic behavior. His book also teaches evolution as a process over time that accounts for the diversity of all life. -
Beadle and Tatum publish the 1 gene-1 enzyme hypothesis
This hypothesis was proposed by George Wells Beadle, it is that each gene directly produces a single enzyme. Beadle proved this by showing that one gene in a fruit fly controlled a specific chemical reaction in the fruit fly. This experiment leads researchers to characterize genes as chemical molecules. https://embryo.asu.edu/pages/george-w-beadles-one-gene-one-enzyme-hypothesis -
Jacques Cousteau develops SCUBA
Jacques Cousteau teamed up with Emile Gagnan in 1942, an engineer who worked for Air Liquide. By 1943, they had designed and tested a scuba allowing dives longer than an hour at significant depths. They called it the Aqua-Lung; it was the first efficient scuba set. -
Avery, MacLoed and McCarty determine that DNA is the molecule that carries the genetic code
The Avery–MacLeod–McCarty experiment was reported in 1944 by Oswald Avery, Colin MacLeod, and Maclyn McCarty, they concluded that DNA is the substance that causes bacterial transformation. Nucleic acids carry the genetic code that determines the order of amino acids in proteins. -
The first atomic bomb is used in war
Two atomic bombs were dropped on Japan during World War II, The code name of the uranium-based bomb was "Little Boy."
192,020 people were killed in Hiroshima. https://www.cnn.com/2013/08/06/world/asia/btn-atomic-bombs/index.html -
Ensatina described as a ring species
Robert Stebbins find that these salamanders evolved into multiple subspecies with adaptations for living in different environments. This populayion migrated south for better weather conditions.
ps://evolution.berkeley.edu/evolibrary/article/0_0_0/devitt_02 -
Rosalind Franklin works with DNA and X-Ray crystallography and develops “Image 51”
On May 1952, this image became a data source that led to the development of the DNA model and confirmed the prior double helical structure of DNA, which were presented by Raymond Gosling. https://en.wikipedia.org/wiki/Photo_51 -
Hershy-Chase experiments are published
The Hershey-Chase experiment became known as the "blender experiment, this experiment was the reason DNA was the genetic material. The scientists separated the protein coating from the nuclei of bacteriophages, the viruses that infect bacteria. -
Miller-Urey experiments published
This experiment is the classic experiment on the origin of life. Stanley Miller and Harold Urey were attempting to figure out what environments or conditions were necessary to allow life to begin. http://www.juliantrubin.com/bigten/miller_urey_experiment.html -
Watson and Crick propose the double helix model of DNA structure
James Dewey Watson and Francis Harry Compton Crick were scientists studying the structure of DNA. They found that the structure of DNA was a double-helix polymer or a spiral of two DNA strands. Each contained a chain of monomer nucleotides. http://www.bbc.co.uk/history/historic_figures/watson_and_crick.shtml -
Meselson and Stahl work with DNA replication
The Meselson–Stahl experiment is an experiment by Matthew Meselson and Franklin Stahl in 1958 which supported Watson and Crick's hypothesis that DNA replication was semiconservative. -
Nirenberg cracks the genetic code
Marshall Nirenberg focused on how DNA directs protein synthesis and the role of RNA. He used a synthetic messenger RNA (mRNA) strand that contained only uracils (U), yielded a protein that contained only phenylalanines. -
Endosymbiosis is described by Lynn Margulis
Dr. Margulis researched eukaryotic cells, she reviewed all the data on prokaryotes, eukaryotes, and organelles. She concluded that the similarities between prokaryotes and organelles could best be explained by endosymbiosis -
Apollo 11 lands on the moon
Apollo 11 was the first manned mission to land on the moon. Commander Neil Armstrong and pilot Buzz Aldrin landed were the two men in Apollo 11. As Armstrong said "That's one small step for man, one giant leap for mankind,"The spacecraft was launched from Cape Kennedy at 13:32:00 UT on July 16, 1969. https://airandspace.si.edu/explore-and-learn/topics/apollo/apollo-program/landing-missions/apollo11.cfm -
Barbara McClintock describes transposons
Thanks to the accomplishments in molecular biology l the discovery of transposons in other organisms was able to happen. Transposons constitute more than 65% of our genomes and approximately 85% of the maize genome -
Theodosius Dobzhansky publishes “Nothing in Science Makes Sense Except in the Light of Evolution.”
A Ukrainian-American geneticist and evolutionist whose work had a major influence on 20th-century research on genetics and evolutionary theory, wrote this essay in 1973. He criticized anti-evolution creationism and espousing theistic evolution. -
Australopithecus afarensis nicknamed "Lucy" fossil discovered
This is one of the best-known early human species, However; they had both ape and human characteristics. This species had a flat nose, a strongly projecting lower jaw like an ape. They also had long, strong arms with curved fingers to climb trees. This species had small canine teeth like early humans and stood on two legs. https://australianmuseum.net.au/australopithecus-afarensis -
Spliceosomes were discovered and described
Only eukaryotes have spliceosomes they selectively cut out irrelevant introns from the initial primary transcript. Every human cell contains about 100,000 spliceosomes, which are responsible for removing over 200,000 different intron sequences -
The Sanger Technique is developed
Frederick Sanger developed the “rapid DNA sequencing” technique also known as the Sanger method. It helps determine the order of bases in a strand of DNA https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4727787/. -
Deep sea hydrothermal vents and associated life around them are discovered
scientists exploring the Galápagos Rift along the mid-ocean ridge in the eastern Pacific observed temperature spikes in their data. The scientists had discovered deep-sea hydrothermal vents. They also came across unique ecosystems, hundreds of new species that existed around the vents -
Kary Mullis develops Polymerase Chain Reaction
Mullis was a Nobel Prize-winning American biochemist, author, and lecturer. During his seven years at a Corporation in Emeryville, California he researched oligonucleotide synthesis and invented the polymerase chain reaction. A method of amplifying DNA, PCR multiplies a single, microscopic strand of the genetic material billions of times within hours. -
Tommie Lee Andrews is convicted of rape
Tommie Lee Andrews was the first American ever to be convicted in a case that utilized DNA evidence.An expert in genetics analysis had testified that the DNA fingerprint of Tommy Lee Andrews' blood matched that of the rapist's semen. ps://ransombiotechproject.weebly.com/tommie-lee-andrews-rape.html -
"Reproductive Isolation as a Consequence of Adaptive Divergence in Drosophila pseudoobscura" Published.
Two ways to classify isolating mechanisms is premating isolation where mating does not occur and postmating isolation where mating occurs but the offspring is nonfertile. To determine which mechanism is going to develop first, eight populations of Drosophila pseudoobscura were studied.
https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1558-5646.1989.tb02577.x -
Plasmodium falciparum is described as the causative agent of malaria
Plasmodium falciparum is the deadliest species of Plasmodium that cause malaria in humans. Patrick Mason hypothesized that female mosquitoes could transmit malaria. This was proven true by Giovanni Battista Grassi and Ronald Ross -
The Innocence Project is founded
This is a non-profit legal organization that is committed to exonerating wrongly convicted people through the use of DNA-testing and to reforming the criminal justice system to prevent future injustice. It was founded by Barry Scheck and Peter Neufeld. https://www.innocenceproject.org/about/ -
CRISPr/CAS 9 is identified and described
Francisco Mojca found what is now called CRISPr locus. He worked on them throughout the 1990’s, he recognized that what had been reported as disparate repeat sequences
www.broad.institue.org -
Dolly the sheep is cloned
Dolly was part of an experiment to develop a better way to produce genetically modified livestock. Dolly was cloned from an adult somatic cell, using the nuclear transfer. She came from 3 other sheep, one provided the egg, another the DNA and a third carried the cloned embryo. http://dolly.roslin.ed.ac.uk/facts/the-life-of-dolly/index.html -
Sahelanthropus tchadensis fossil discovered
Sahelanthropus tchadensis is an extinct species a that is dated to about 7 million years ago. This species had skull features of an ape and walked upright like humans. Due to the teeth, it is believed that thier diet consisted of leaves, fruits, seeds, roots, nuts, and insects. -
Human genome is fully sequenced
A genome is the complete set of DNA. DNA molecules are made up of nucleotide bases: adenine, thymine, guanine, and cytosine. The bases on each strand pair as follows; A always pairs with T, and C always with G.The human genome contains approximately 3 billion of these base pairs, which stay in the 23 pairs of chromosomes within the nucleus of all our cells -
Homo denisova fossil discovered
There was a discovery of a finger bone fragment belonging to a juvenile female who might have lived 41,000 years ago. It was found in the Denisova Cave in the Altai Mountains in Siberia. The nuclear genome from this finger bone showed that Denisovans shared a common origin with Neanderthals and that they lived among and interbred with the ancestors of some modern humans http://www.sciencemag.org/news/2017/03/ancient-skulls-may-belong-elusive-humans-called-denisovans -
Richard L Bible is executed
Richard Lynn Bible was announced dead at 11:11 am by a lethal injection on Thursday in Florence. He was executed for the murder he committed in 1988 murder. This was one of the first use of DNA technology in an Arizona murder case
