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157
Galen of Pergamon describes the human body
Galen studied anatomy and physiology, and his theories infuenced western medicine for !,300 years.
“Galen.” Wikipedia, Wikimedia Foundation, 20 Nov. 2017, en.wikipedia.org/wiki/Galen. -
1546
The Germ Theory of Disease is published
The theory states that diseases are caused by microorganisms. It was proposed by Girolamo Fracastoro in 1546, and expanded upon by Marcus von Plenciz in 1762. The more formal experiments between germs and disease were performed in 1860.
“Germ Theory of Disease.” Wikipedia, Wikimedia Foundation, 15 Nov. 2017, en.wikipedia.org/wiki/Germ_theory_of_disease. -
Lamarck develops Hypothesis of Evolution by Means of Acquired Characteristics
Lamarck hypothesized that modifications that occur during an organism's lifetime are passed on to its offspring, and that body parts that are used become larger and stronger, while body parts that aren’t used wither away and disappear.
“Inheritance of Acquired Characteristics.” Wikipedia, Wikimedia Foundation, 27 Oct. 2017, en.wikipedia.org/wiki/Inheritance_of_acquired_characteristics. -
The Voyage of the HMS Beagle
The main purpose of the expedition was to conduct a hydrographic survey of south America. Darwin was onboard as a naturalist. He mainly studied geology, but also took extensive notes on zoology on this voyage, which he later used in his theories on natural selection. “Second Voyage of HMS Beagle.” Wikipedia, Wikimedia Foundation, 2 Nov. 2017, en.wikipedia.org/wiki/Second_voyage_of_HMS_Beagle. -
regor Mendel Publishes Works on Inheritance of Traits in Pea Plants
By breading pea plants and observing their characteristics, Mendel discovered dominant and recessive traits and their patterns of inheritance.
“Gregor Mendel.” Wikipedia, Wikimedia Foundation, 20 Nov. 2017, en.wikipedia.org/wiki/Gregor_Mendel. -
Louis Pasteur Refutes Spontaneous Generation
Louis Pasture demonstrated that without contamination, microorganisms could not develop. His experiments proved that in sealed flasks, no organisms grew. He then used flasks with curved swan necks, that allowed air to enter. In these flasks, no organisms grew unless the flasks were titled. “Louis Pasteur.” Wikipedia, Wikimedia Foundation, 16 Nov. 2017, en.wikipedia.org/wiki/Louis_Pasteur. -
The Origin of Species by Means of Natural Selection is published
Darwin’s book concluded that Natural Selection was the basic mechanism of evolution; those most suited for the environment survived and thus passed on their more favorable genes to their offspring.
“Charles Darwin.” SparkNotes, SparkNotes, www.sparknotes.com/biography/darwin/section10.rhtml. -
Plasmodium falciparum is described as the causative agent of malaria
Malaria is transmitted to humans by mosquito bite. The parasite moves to the liver and reproduces. The daughter cells are then released into the bloodstream.
“Plasmodium Falciparum.” Wikipedia, Wikimedia Foundation, 14 Nov. 2017, en.wikipedia.org/wiki/Plasmodium_falciparum. -
Hardy and Weinberg independently develop the Hardy-Weinberg equation
A mathematical equation that can be used to determine the genetic variation of a population. “Hardy-Weinberg Equation.” Nature News, Nature Publishing Group, www.nature.com/scitable/definition/hardy-weinberg-equation-299. -
T. Hunt Morgan discovers sex-linkage
By breading fruit flies, he discovered that certain traits were inherited on the sex chromosomes. Miko, Ilona. “Thomas Hunt Morgan and Sex Linkage.” Nature News, Nature Publishing Group, www.nature.com/scitable/topicpage/thomas-hunt-morgan-and-sex-linkage-452. -
Neils Bohr develops the Bohr model of atom structure
He depicted the atom with a small nucleus surrounded by electrons that orbit the nucleus. “Bohr Model.” Wikipedia, Wikimedia Foundation, 11 Nov. 2017, en.wikipedia.org/wiki/Bohr_model. -
Frederick Griffith describes the process of transformation
Griffith was the first to show bacteria can change their form and function. “Frederick Griffith.” Wikipedia, Wikimedia Foundation, 16 Nov. 2017, en.wikipedia.org/wiki/Frederick_Griffith. -
Avery, MacLoed and McCarty determine that DNA is the molecule that carries the genetic code
Avery–MacLeod–McCarty experiment suggested that DNA, rather than protein as widely believed at the time, may be the hereditary material of bacteria, and thus higher organisms as well. “Avery–MacLeod–McCarty Experiment.” Wikipedia, Wikimedia Foundation, 14 Nov. 2017, en.wikipedia.org/wiki/Avery%E2%80%93MacLeod%E2%80%93McCarty_experiment. -
Rosalind Franklin works with DNA and X-Ray crystallography and develops “Image 51”
Image 51 is an X-ray diffraction image that was crucial for or developing a model of DNA. “Rosalind Franklin.” Wikipedia, Wikimedia Foundation, 19 Nov. 2017, en.wikipedia.org/wiki/Rosalind_Franklin. “Photo 51.” Wikipedia, Wikimedia Foundation, 14 Nov. 2017, en.wikipedia.org/wiki/Photo_51. -
Hershey-Chase experiments are published
Alfred Hershey and Martha chase published a series of experiments that helped confirm DNA is genetic material, refuting the previous idea that protein carried genetic information. http://jgp.rupress.org/content/jgp/36/1/39.full.pdf “Hershey–Chase Experiment.” Wikipedia, Wikimedia Foundation, 14 Nov. 2017, en.wikipedia.org/wiki/Hershey%E2%80%93Chase_experiment. -
Watson and Crick propose the double helix model of DNA structure
Watson and crick used cardboard cutouts to fit the four DNA bases together (Adenine with Thymine and Cytosine with Guanine), with hydrogen bonds holding them together- creating a three dimensional model of the double helix structure. Pray, Leslie A. “Discovery of DNA Structure and Function: Watson and Crick.” Nature News, Nature Publishing Group, www.nature.com/scitable/topicpage/discovery-of-dna-structure-and-function-watson-397. -
Meselson and Stahl work with DNA replication
Meselson and Stahl proved the semiconservative model of DNA replication was correct.
“Meselson–Stahl Experiment.” Wikipedia, Wikimedia Foundation, 14 Nov. 2017, en.wikipedia.org/wiki/Meselson%E2%80%93Stahl_experiment. -
Nirenberg cracks the genetic code
The experiment deciphered the first codon in the genetic code and that RNA controlled production of specific proteins.
“Nirenberg and Matthaei Experiment.” Wikipedia, Wikimedia Foundation, 16 Nov. 2017, en.wikipedia.org/wiki/Nirenberg_and_Matthaei_experiment. -
Endosymbiosis is described by Lynn Margulis
A hypothesis that attempts to explain how Eukaryotic organelles evolved from prokaryotic cells.
Endosymbiosis - The Appearance of the Eukaryotes, www.fossilmuseum.net/Evolution/Endosymbiosis.htm. “Lynn Margulis.” Wikipedia, Wikimedia Foundation, 18 Nov. 2017, en.wikipedia.org/wiki/Lynn_Margulis. -
Apollo 11 Lands on the Moon
Apollo 11 was launched on July 16th, 1969. On July 20 the lunar module landed on the moon, piloted by Buzz Aldrin. Neil Armstrong was the first to set foot on the moon, followed about 20 minutes later by Aldrin. They only spent just over two hours outside on the moon collecting specimens before returning to the lunar module. Dunbar, Brian. “July 20, 1969: One Giant Leap For Mankind.” NASA, NASA, 19 Feb. 2015, www.nasa.gov/mission_pages/apollo/apollo11.html. -
Spliceosomes were discovered and described
Genes of higher organisms are "split" or present in several distinct segments along the DNA molecule. The spliceosome removes introns from a transcribed pre-mRNA, sort of like a movie editor cutting unnecessary parts out of film. “Spliceosome.” Wikipedia, Wikimedia Foundation, 3 Nov. 2017, en.wikipedia.org/wiki/Spliceosome. -
The Sanger Technique is developed
The Sanger Technique is a method of DNA sequencing.
“Sanger Sequencing.” Wikipedia, Wikimedia Foundation, 26 July 2017, en.wikipedia.org/wiki/Sanger_sequencing. -
Deep sea hydrothermal vents and associated life around them are discovered
Hydrothermal vents are areas on the earth’s surface where geothermal heated water escapes. Deep sea hydrothermal vents create a habitat for a wide variety of organisms, fueled by the chemicals dissolved in the vent water.
“Hydrothermal Vent.” Wikipedia, Wikimedia Foundation, 16 Nov. 2017, en.wikipedia.org/wiki/Hydrothermal_vent. -
Kary Mullis develops Polymerase Chain Reaction
A technique that copies sections of DNA
“Polymerase Chain Reaction.” Wikipedia, Wikimedia Foundation, 19 Nov. 2017, en.wikipedia.org/wiki/Polymerase_chain_reaction. -
The Innocence Project is founded
The Innocence Project Exonerates the wrongly convicted through DNA evidence.
“Help Us Put an End to Wrongful Convictions!” Innocence Project, www.innocenceproject.org/. -
Dolly the sheep is cloned
Dolly the sheep was the first mammal successfully cloned. “Cloning Dolly the Sheep.” Cloning Dolly the Sheep, www.animalresearch.info/en/medical-advances/timeline/cloning-dolly-the-sheep/. -
Sahelanthropus Tchadensis Fossil Discovered
The fossils were discovered in the deserts of chad by a team of four French scientists. The fossil is believed to be the oldest human ancestor after the human line split from the chimpanzee line, and the fossil shows characteristics of both humans and chimpanzees. “Sahelanthropus Tchadensis.” Sahelanthropus Tchadensis | The Smithsonian Institution's Human Origins Program, 1 Mar. 2010, humanorigins.si.edu/evidence/human-fossils/species/sahelanthropus-tchadensis. -
Human Genome is Fully Sequenced
In the world’s largest collaborative biological process, scientists from seven countries created a “map” of the DNA sequence of the euchromatic human genome. “2003 Release: International Consortium Completes HGP.” National Human Genome Research Institute (NHGRI), www.genome.gov/11006929/2003-release-international-consortium-completes-hgp/. “Human Genome Project.” Wikipedia, Wikimedia Foundation, 13 Nov. 2017, en.wikipedia.org/wiki/Human_Genome_Project. -
CRISPr/CAS 9 is identified and described
Technology that enables geneticists and medical researchers to edit parts of the genome by removing, adding or altering sections of the DNA sequence. “CRISPR Timeline.” Broad Institute, 6 Jan. 2017, www.broadinstitute.org/what-broad/areas-focus/project-spotlight/crispr-timeline. “What Are Genome Editing and CRISPR-Cas9? - Genetics Home Reference.” U.S. National Library of Medicine, National Institutes of Health, ghr.nlm.nih.gov/primer/genomicresearch/genomeediting. -
Richard L Bible is executed
Bible’s case was the first in Arizona to use DNA evidence. He was convicted and executed 23 years after the murder.
Enea, Joe. “Death Row Diaries: The First Use of DNA Technology in an Arizona Murder Case.” KNXV, 18 June 2016, www.abc15.com/news/crime/death-row-diaries-the-first-use-of-dna-technology-in-an-arizona-murder-case.
