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162 BCE
Galen of Pergamum describes the human body
Due to the social taboo of disecting human corpses, Galen only disected apes, pigs, sheep and goats. Although some of his ideas about the human body were wrong, like the thought we only have 3 connected systems. He discovered arteries carry blood and not air and described the heart valve among other things. -
Jean Baptiste Lamarck
Lamarck shared the hypothesis of evolution by means of acquired characteristics, he thought organisms can change during their life to adapt to their environments. Lamarck believed the changes made will pass to their offspring. He used the theory that giraffes used to have short necks but grew long necks over time to reach the higher leaves in trees.
http://necsi.edu/projects/evolution/lamarck/lamarck/lamarck_lamarck.html -
The Voyage of the HMS Beagle
Charles Darwin boarded the HMS Beagle and traveled the world. He left from Plymouth, England. Some places he went were Cape Verde Islands and made observations about cuddle fish. Brazil and explored the rain forest. He took a 5 year journey exploring the world.
Cite:https://www.aboutdarwin.com/voyage/voyage03.html -
Alfred Russel Wallace published ideas of evolutionary processes
Russell independently came to the conclusion of a natural, observable way for life to change; something Darwin would call natural selection. The men corresponded briefly and Darwin was shocked when Wallace sent him a his theory in 1858, because it almost replicated Darwin's theory. Wallace's theory became overlooked as Darwin's theory and book became popular.
Cite:http://evolution.berkeley.edu/evolibrary/article/history_14 -
Louis Pasteur refutes spontaneous generation
Pasteur created a controlled experiment where he took broth and kept it sterile from bacteria. The results refuted that bacteria are spontaneous grow microbial life. It still took years of germ theory to completely refute the theory that bacteria came from nothing.
Cite:https://www.boundless.com/microbiology/textbooks/boundless-microbiology-textbook/introduction-to-microbiology-1/in -
The Origin of species by means of Natural Selection is published
Charles Darwin published "The Origin of species by means of natural selection"; by 1872 the book had already had six editions published because it was so popular. Darwin argued that organisms gradually evolve through a process called "natural selection", genetic variations to suit the environment.
Cite:http://www.history.com/this-day-in-history/origin-of-species-is-published -
Gregor Mendel publishes works on inheritance of traits in pea plants
Mendel created the theory of inheritance by studying and cross breeding pea plants to discover that traits are inherited, Some traits are recessive while others are dominant
Cite:https://www.sciencelearn.org.nz/resources/2000-mendel-s-principles-of-inheritance -
Hardy-Weinberg equation for determining allele frequencies in population
Hardy and Weinberg describe a basic principle of population genetics. p2 + 2pq + q2 = 1 where p is the frequency of the "A" allele and q is the frequency of the "a" allele in the population. In the equation, p2 represents the frequency of the homozygous genotype AA, q2 represents the frequency of the homozygous genotype aa, and 2pq represents the frequency of the heterozygous genotype Aa.
cite:https://www.nature.com/scitable/definition/hardy-weinberg-equation-299 -
T. Hunt Morgan discovers sex-linkage
Morgan discovered one of his fruit flies had white eyes instead of red. Upon further experimentation he discovered Mendelian's Theory of Inheritance of dominant and recessive traits could apply. He discovered the eye color of the fruit fly was an expressed sex-link trait.
Cite http://www.genomenewsnetwork.org/resources/timeline/1910_Morgan.php -
Neils Bohr develops the Bohr model of the atom structure
Earnest Rutherford and Neils Bohr develop a structure that depicts the atom as a small, postively charged nucleus. It is surrounded by electrons that travel in rotation like a solar system. The model was shortened to just being called Bohr model.
Cite:https://en.wikipedia.org/wiki/Bohr_model -
Fredrick Griffith describes the process of transformation
It was the first experiment showing bacteria can get DNA through transformation. His experiment with living bacteria changed physical form.
Cite: https://education.llnl.gov/bep/science/10/tLect.html -
Theodosius Dobzhansky publishes Genetics and the Origin of Species
Dobzhansky's book implements theories of mutation, natural selection and speciation to explain habits of populations & resulting effects on their genetic behavior.
Cite:https://en.wikipedia.org/wiki/Genetics_and_the_Origin_of_Species -
Beadle & Tatum publish the 1-gene 1-enzyme hypothesis
The hypothesis is that each gene produces a single enzyme thta affects a single step in a metabolic way.
Cite:https://embryo.asu.edu/pages/george-w-beadles-one-gene-one-enzyme-hypothesis -
Ernst Mayr develops the biological species concept
He said" Species are groups of interbreeding natural populations that are re productively isolated from other such groups."
cite:https://www.blackwellpublishing.com/ridley/a-z/Biological_species_concept.asp -
Jacques Cousteau develops SCUBA
Cousteau wanted a device that combined compressed-air cylinders and regulators that would supply air on demand underwater. With the help of Gagnan they invented the aqua-lung. In 1946 the aqua-lung was mass produced.
Cite:https://www.deepblu.com/post/81641b20107c11e7aa9ad181bc785596 -
Avery, MacLoed and McCarty determine that DNA is the molecule that carries the genetic code
Avery. Macleod. McCarthy worked with bacterium that caused pneumonia to help demonstrate the role of DNA as a carrier of genetic info.
Cite:http://www.yourgenome.org/stories/revealing-dna-as-the-molecule-of-life -
Barbara McClintock describes transposons
Barbara discovered some chromosomes could be mobile. The mobile chromosomes are called transposons, and depending where they insert themselves in a chromosome can alter the expression of the other genes.
Cite:http://www.pnas.org/content/109/50/20198.full.pdf -
Hershey-Chase experiments are published
Chase and Hershey used the findings by Avery, McCleod and McCarthy and used a T2 virus to investigate if genetic info is passed by DNA or proteins. Using radioactive material they concluded DNA carries out instructions to make new viruses.
Cite:http://www.yourgenome.org/stories/revealing-dna-as-the-molecule-of-life -
Watson and Crick propose the double helix model of DNA structure
The double helix is a twisted ladder structure of DNA. Clark and Watson used Rosalind Frankin's x-ray technique to prove that DNA is a double helix. Until then, researchers used the term "gene" to mean the smallest unit of genetic info.
Cite:https://profiles.nlm.nih.gov/SC/Views/Exhibit/narrative/doublehelix.html -
Rosalind Franklin works with DNA and Xray crystallography and develops "image 51"
Franklin crystallized a form of a molecule like DNA and exposed it to x-rays. The x-rays were deflected by atoms in the crystal, forming diffraction patterns. Image 51 is a famous x-shaped image that made Franklin suggest a 2 strand structure for DNA
Cite:http://www.technology.org/2014/02/04/explainer-x-ray-crystallography/ -
Miller-Urey experiments published
In 1952 biochemists Miller and Urey conduct experiments to demonstrate several organic compounds could form spontaneously by simualting the conditions of earths early atmosphere. They mixed gases over a pool of water (earths early ocean). Several organic amino acids formed from inorganic material.
Cite:http://www.windows2universe.org/earth/Life/miller_urey.html -
Meselson & Stahl confirm DNA replication
Meselson & Stahl meet in 1954 and by 1958 have proven the hypothesis that DNA replication was semiconservative. The hypothesis was originally made by Watson & Crick a few years prior. It meant the two strands of the double helix will separate during replication and act as a template to synthesize two new strands.
Cite:https://www.khanacademy.org/science/biology/dna-as-the-genetic-material/dna-replication/a/mode-of-dna-replication-meselson-stahl-experiment -
Nirenberg cracks the genetic code
Nirenberg discovers the 1st "triplet" out of 64 triplet codons in genetic coding by using the RNA to translate specific amino acids
Cite:http://www.genomenewsnetwork.org/resources/timeline/1961_Nirenberg.php -
Lynn Margulis describes endosymbiosis
The theory of endosymbiosis is that prokaryotic organisms were independent and cooperative. They engulfed each other and survived and became eukaryotic cells. -
Australopithicus afarensis nicknamed “lucy” fossil discovered
Lucy's other common name is AL-288-1, which is several hundred pieces of bone fossils representing 40% of a female hominin species. She was found in what is today Ethiopia. She is estimated to be 3.2 million years old
Cite:https://australianmuseum.net.au/australopithecus-afarensis -
The Sanger Technique is developed
Fredrick Sanger develops a classical "rapid DNA sequencing." It determines the order of bases in each DNA strand.
Cite: https://unlockinglifescode.org/timeline/11 -
Spliceosomes were discovered and described
Eukaryotic genes are expressed as precursor mRNA's and converted to mRNA's by splicing. Pre-mRNA splicing is catalyzed by the spliceosomes, a multimegadalton ribonucleoprotein (RNP).
Cite; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3119917/ -
Deep sea Thermal Vents
Hydro-thermal vents (like geysers or hot springs) on the ocean floor were discovered by scientists exploring along the mid-ocean ridge in the eastern Pacific. The vents change water temperatures from near freezing to 750 degrees Fahrenheit. Hundreds of new species and bacteria thrive around the vents.
Cite:https://www.nationalgeographic.org/media/deep-sea-hydrothermal-vents/ -
Kary Mullis develops Polymerase Chain Reaction
In the spring of 1985, Kary Mullis develops polymerase chain reaction that allows scarce DNA samples to be copied millions of times. This has brought breakthroughs in areas of science and medicine. It has helped diagnose genetic disorders, Aids detection and helped criminologists compare evidence with suspect samples.
Cite:http://siarchives.si.edu/research/videohistory_catalog9577.html -
Tommie Lee Andrews is convicted of rape
Andrews is the 1st defendant in the U.S. to be convicted of rape using DNA evidence. He was convicted of raping a 27 year old woman in Orlando based off of DNA samples from the rapists semen, victims blood and blood taken from Andrews after his arrest.
Cite:http://www.nytimes.com/1988/02/06/us/rapist-convicted-on-dna-match.html -
The Innocence Project was founded
Founded by Peter Neufeld and Barry Scheck at Cardozo School of Law. They use DNA testing to prove wrongly convicted inmates are innocent. They also help prevent other injustices from happening with reforms in the criminal justice system.
Cite: https://www.innocenceproject.org/about/ -
Dolly the sheep cloned
Scientists at The Roslin Institute produced a cloned sheep from a mamary gland of a six-year-old Finn Dorset sheep and an egg from a Scottish Blackface sheep. The experiment was to determine how cells change during development and if a cell such as skin or brain cells can produce a whole new animal.
Cite http://dolly.roslin.ed.ac.uk/facts/the-life-of-dolly/ -
Sahelanthropus tchadensis fossil discovered
One of the oldest known species in the human family tree. Believed to live 6-7 million years ago in west-central Africa and walked upright.
Cite:http://humanorigins.si.edu/evidence/human-fossils/species/sahelanthropus-tchadensis -
Human genome is fully sequenced
The Human Genome Project is completed, it contains 3 billion base pairs in 23 pairs of chromosomes.
Cite:https://www.genome.gov/11006943/human-genome-project-completion-frequently-asked-questions/ -
CRISPr/CAS9 is identified and described
A genome editing tool used to edit parts of the genome by removing, adding adn altering sections of the DNA sequence. CAS9 is an enzyme like a pair of molecular scissors.
Cite:https://www.broadinstitute.org/what-broad/areas-focus/project-spotlight/crispr-timeline -
Homo denisova fossil discovered
A finger bone was found in Denisova cave in the Altai Mountains in Southern Siberia. Mitochondrial DNA couldn't place it as neanderthal or modern human. It is believed to be an unknown species we now call, Denisovan.
Cite:http://www.talkorigins.org/faqs/homs/denisova.html -
Richard L Bible Executed
On June 30, 2011 Bible was executed for the rape and murder of a 9 year old girl in Flagstaff, AZ that happened in 1988. Hair found on the girl was deemed similar to Bible's along with some matching fibers and the girls blood found on his shirt.
Cite:http://archive.azcentral.com/news/articles/20110630arizona-execution-richard-lynn-bible.html
