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200 BCE
Galen of Pergamon describes the human body
He regarded anatomy as the foundation of medical knowledge, and he frequently dissected and experimented on such lower animals. His goal was to advocate for improving surgical skills and research. He was able to observe structural differences within the body as well. -
1546
The Germ Theory of Disease is published
This theory claims that diseases are caused by microorganisms. They are too small to see with the human eye, but when they invade hosts. They reproduce and cause disease. These microorganisms that cause disease are called pathogens, and the -
Aristotle describes life with the Scala Naturae 1700s
Scala Naturae was described as another term for divine order or natural selection. It was believed that there was an order to beings lives. And that different classes of beings which together make up the universe and that the ideas of God make up the food chain. -
Lamarck develops Hypothesis of evolution by means of acquired characteristics
Lamarck hypothesizes that evolution is defined by characteristics that over time are acquired by a population. It was found that if an organism changes during life in order to adapt to its environment, those changes are passed on to its offspring. Lamarck also believed that evolution happens according to a predetermined plan and the result is already determined. -
The Voyage of the HMS Beagle
The Beagle was the ship used by Darwin on his expeditions to explore the world. He discovered populations of creatures with various adaptations unique to themselves. After visiting several islands Darwin was able to complete one of his series of books. -
Alfred Russel Wallace published ideas of evolutionary processes
Wallace was a pivotal part of the theory of evolution. During his expedition to observe wildlife he developed some of the biggest ideas about evolution. Wallace came to the conclusion that things evolve and that they adapt to their environment.
diseases they cause are called infectious diseases. -
Gregor Mendel publishes works on inheritance of traits in pea plants
Through pea plants, Mendel discovered the basic laws of inheritance. He was able to determine that these traits come in gene pairs which you get from your parents. He also was able to follow the traits and determine that some are recessive. -
The Origin of species by means of Natural Selection is published
In 1859, Darwin published The Origin of species by means of Natural Selection. It has been known to be the basis of evolutionary biology. He described that populations evolve to increase their chances of survival and over time pass down these traits. -
Louis Pasteur refutes spontaneous generation
Louis Pasteur designed an experiment to test whether sterile nutrient broth could spontaneously generate microbial life. He added nutrient broths to two flasks, after sterilizing them, he opened the flasks to the air above. One flask had dust enter the flask while another only had dust around the flasks rim. This refuted spontaneous generation. -
The Challenger Oceanography Expedition sails around the world
The voyage sailing around the world allowed for oceanography to gain a foundation. The ship was able to find over 4,000 new species and cataloged all of them. This was one of the biggest new advances in the knowledge of the earth to date. -
Plasmodium falciparum is described as the causative agent of malaria
This a unicellular parasite of humans, and the deadliest species that cause malaria in humans. The parasite was first found within mosquitos. And is regarded as the deadliest parasite in humans, causing a conservative estimate of one million deaths every year. -
T. Hunt Morgan discovers sex-linkage
His experiment began by breeding only fruit flies. He hoped to find large scale mutations which would create new species. This was not what happened and because of this Morgan confirmed Mendelian laws of inheritance and the hypothesis that genes are located on chromosomes. -
Hardy and Weinberg independently develop the Hardy-Weinberg equation for determining allele frequencies in populations
It is a mathematical equation describing the distribution and expression of alleles in a population. It expresses the conditions under which allele frequencies are expected to change. This helped biologists form punnet squares to predict the frequencies. -
Neils Bohr develops the Bohr model of atom structure
Bohr depicts the atom as a small, positively charged nucleus. This nucleus is surrounded by electrons that travel in circular orbits around the nucleus. He found that these electrons are pulled to the nucleus by electrostatic forces -
Frederick Griffith describes the process of transformation
This was one of the first experiments showing that bacteria can get DNA through a process called transformation. They showed how the bacteria would infect mice and have the ability to spread. As well as how certain strains were able to kill their hosts. -
Theodosius Dobzhansky publishes Genetics and the Origin of Species
This book spread knowledge about population genetics to many other biologists. His book details evolutionary problems. And also helped explain diversity in life. -
Jacques Cousteau develops SCUBA
Cousteau was the first person to create modern scuba diving. He was also able to raise awareness to marine life and endangerment problems they are faces with. He and another partner were able to create a valve system to allow divers to dive deeper and for longer. He was also able to develop films about his ocean adventures to draw people in to the amazing ocean world. -
Beadle and Tatum publish the 1 gene-1 enzyme hypothesis
This is the idea that genes act through the production of their enzymes. Each of these genes are responsible for producing a single enzyme that in turn affects a single step in a metabolic pathway. This was the first significant result from molecular biology. -
Avery, MacLoed and McCarty determine that DNA is the molecule that carries the genetic code
DNA is the substance that causes bacterial transformation. And within an era when it had been widely believed that it was proteins that served the function of carrying genetic information this changed biology. It was then determined DNA was the molecule for life. -
The first atomic bomb is used in war
During the cold war, an American B-29 bomber, dropped the world’s first atom bomb, over the city of Hiroshima. This bomb killed over 100,000 people and injured tens of thousands more. This was to mark the end of the war and prevent further invasions. -
Miller-Urey experiments published
These biochemists conducted an experiment which demonstrated that several organic compounds could be formed spontaneously. They were able to do this by simulating the conditions of Earth's early atmosphere to create these compounds. It was believed after the experiment that chemical reactions synthesized more complex organic compounds from simpler inorganic. -
Barbara McClintock describes transposons
This study discovered that gene replication does not always follow a consistent pattern. That as a result showed that at different stages of seed development, the genes of maize kernels are capable of producing a variety of coloration patterns to produce variation. This completely changed theories on gene inheritance. -
Hershey-Chase experiments are published
This experiment was able to determine that DNA is genetic material and not protein. The two decided to track the transfer of proteins and DNA between a virus and its host. They introduced the phage culture to the bacterial sample, they used a blender to violently disturb the infected bacteria. This caused the protein shells to detach from their hosts and then using a centrifuge, they separated the bacterium from the phages and protein. -
Watson and Crick propose the double helix model of DNA structure
It was discovered that DNA was wrapped in a double helix. They also found that DNA was twisted and it has opposite bases which connect. These finds helped further the knowledge about biology and DNA. -
Ensatina described as a ring species
Ensatina is a ring species as multiple similar species all began to interbreed with each other. As the species began to spread down the central valley they began to interbreed less and less. This was caused by the populations new adaptations and evolutionary changes they soon were incompatible with one another. -
Meselson and Stahl work with DNA replication
This experiment confirmed what Watson and Crick studied about DNA. This means that when the double stranded DNA helix is replicated Each of the two new double-stranded DNA helices consisted of one strand from the original helix and one newly synthesized. -
Nirenberg cracks the genetic code
The experiment deciphered the first of the 64 triplet codons in the genetic code by using nucleic acid homopolymers to translate specific amino acids. He found extracts from bacterial cells that could make protein even when no intact living cells were present was prepared. This cracked the first codon of the genetic code and showed that RNA controlled the production of specific types of protein. -
Endosymbiosis is described by Lynn Margulis
Lynn found that cells live together and mutually benefit each other. She also found that mitochondria are the result of endocytosis of aerobic bacteria. As well as chloroplasts are the end result of endocytosis of photosynthetic bacteria. -
Endosymbiosis is described by Lynn Margulis
Lynn found that cells live together and mutually benefit each other. She also found that mitochondria are the result of endocytosis of aerobic bacteria. As well as chloroplasts are the end result of endocytosis of photosynthetic bacteria. -
Australopithicus afarensis nicknamed “lucy” fossil discovered
This southern ape fossil was found in southern Africa. This fossil which is closely related to humans was uncovered in the 1970’s. Lucy was an almost complete skeleton and was the most popular among fossils found. She was a fully grown ape and was bipedal. -
Theodosius Dobzhansky publishes “Nothing in Science Makes Sense Except in the Light of Evolution.”
This book criticizes anti-evolution creationism. It also aimed to assert the importance of organismic biology in response to the challenge of the rising field of molecular biology. -
The Sanger Technique is developed
This is a method of DNA sequencing. It is based on the selective incorporation of chain-terminating nucleotides by DNA polymerase during DNA replication. This sequencing was widely used for many years and still is on smaller scale sequencing. -
Dolly the sheep is cloned
Dolly was the first animal that was successfully cloned by adult somatic cells. The production of a healthy clone therefore proved that a cell taken from a specific part of the body could recreate a whole individual. This was a huge accomplishment for scientists and helped further the community. -
Deep sea hydrothermal vents and associated life around them are discovered
Scientists exploring the Galapagos Rift found deep sea hydrothermal vents. They also happened to find a new ecosystem with brand new species and life. These species were also thriving and using energy created by bacteria surrounding the hot springs. -
Kary Mullis develops Polymerase Chain Reaction
Mullis’ studies gave new ability to replicate DNA. This allows scientists to make millions of copies of a scarce sample of DNA. It also affected evolutionary studies because large quantities of DNA can be manufactured from fossils. -
Human genome is fully sequenced
The human genome for centuries was a mystery and was unable to be fully sequenced in 1988. This genome was built from several different people’s DNA sequences. It was headed by a special committee however it still is missing about 1% of the complete genome. -
Tommie Lee Andrews is convicted of rape
Andrews was part of a court case trying to convict him of rape. Scientists were able to test blood found at the crime scene. Because of this they were able to convict Andrews. -
“Reproductive isolation as a consequence of adaptive divergence in Drosophila pseudoobscrura” published
Drosophila has seen an increase in body size reduction in males. With this increase in smaller males, control females lack interest in them. When paired next to both a small male and a large male the female chooses the large male, and without the large male the female opts to not mate with the small male. When mating with large males however, mortality rates of females has increased and an inflicted harm. As they have began to evolve females have seemed to resist some of the large males harm. -
Apollo 11 lands on the moon
On July 16, 1989 apollo 11 leaves earth and completes 1 and a half orbits around the moon. After several days Neil Armstrong manually improvises a landing onto the moon. One landed Armstrong takes the first steps on another planet, followed closely by Buzz Aldrin. -
The Innocence Project is founded
This project is non-profit legal organization that is committed to proving the innocence of wrongly convicted people. They are able to do this through the use of DNA testing. The goal is to reform the criminal justice system to prevent future injustices. -
Sahelanthropus tchadensis fossil discovered
One of the oldest known species in the human family tree which lived about 6 to 7 million years ago in present day Chad. It was one of the few animals which actually walked upright. The first fossils found was in 2001, but was limited to only cranial specimens. -
Richard L Bible is executed
Bible was convicted of murder in 2005. This came 23 years after the murder was first announced. This murdered was sentenced to a lethal injection. All law officials and lawyers were present to witness the injection. -
Spliceosomes were discovered and described
Spliceosomes are assembled from snRNAs and protein complexes. The spliceosome removes introns from a transcribed pre-mRNA. These help DNA splice and cuts out irrelevant material -
Homo denisova fossil discovered
This fossil was a subspecies of humans. When a fingerbone was found it was genetically distinct from Neanderthals and Humans. It was also found that these creatures interbred with close relatives to humans. -
CRISPr/CAS 9 is identified and described
These are the family of DNA sequences found within bacteria. These sequences contain parts of DNA from viruses that have attacked the bacteria. These snippets are used by the bacteria to detect and destroy DNA from further attacks by similar viruses. -
Rosalind Franklin works with DNA and X-Ray crystallography and develops “Image 51”
This image helped give more detail to how DNA is structured. Because of this image DNA structure was able to be better built. This image later won a Nobel Prize as well as it provided key DNA information.