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Galen of Pergamon
Galen of Pergamon (AD 130-200) was the first of many great anatomists who made multiple achievements in understanding the heart, nervous system, and the mechanics of breathing. Back then, dissection of the human body was forbidden so he performed his dissections on apes. -
Early concepts of Evolution: Jean Baptiste Lamarck
Lamarck became one of the founding professors of the Musse National d'Histoire Naturelle as an expert on invertebrates. He was impressed with the burgeoning fossil record which led him to argue that life was not fixed. Lamarck proposed that an organism adapted to their surroundings, nature also drove them upward from simple forms to increasingly complex ones. He was proposing that life took on its current form through natural processes, not miracle interventions. -
The Voyage of HMS Beagle
Charles Darwin was invited by a professor to join him on the Beagle during the fall of 1831. He took of for sail for the next five years. The Beagle left England on December 27, 1831, reaching the Canary Islands in early January and continuing to south America which they reached by the end of February of 1832. Darwin kept notebooks to record his observations and then would transcribe his notes onto a journal. Summer of 1833, he went to inland with guachos in Argentina. -
Origin of Species published
The origin of species by means of natural selection was discovered by British naturalist Charles Darwin. His theory explained that organisms evolved through a process of "natural selection". Darwin remained silent abut his theory for several years, until British naturalist Alfred Russel Wallace published his own paper that essentially summarized Darwin's theory. His theory on evolution was generally accepted at the time of Darwin's death in 1882. -
Spontaneous Generation
Louis Pasteur created an experiment to test whether sterile nutrient broth could spontaneously generate microbial life. He sterilized the broth to kill off any existing microbes. With his experiments he showed that gravity caused the airborne organisms to settle in the bends and sides of these unique shaped flasks. This finally ended the arguments that unheated air or the infusions themselves contained a vital force necessary for spontaneous generation. -
Mendel's work on inheritance
Johann Gregor Mendel began his research in 1856, involving inheritance patterns in pea plants. In 1865, Mendel presented is results with nearly 30,000 pea plants to local Natural History Society. He was able to present that traits are transmitted faithfully from parents to their offspring independently of other traits and in dominant and recessive patterns. He published his work in 1866, his work went unnoticed by the scientific community. -
Plasmodium Falciparum
Plamodium can infect many animals species such as reptiles, birds, and various mammals. Four species of it have been recognized to infect humans in nature. This is also known as the Malaria parasite.This is found worldwide in tropical and subtropical areas. It can be very serious as it rapidly multiplies in the blood and then cause severe blood loss (anemia). -
Germ Theory of Disease
Scientist Louis Pasteur proved the germ theory of disease. He soon realized that alcohol in wine was produced by yeast which lived on the skin of grapes. During the fermentation process, the yeast appeared to be healthy but lactic acid was formed and the wine turned to vinegar when other microbes were seen among the yeast cells. Through several experiments he was able to show that fermentation required contact with dust. -
Thomas Hunt Morgan and Sex Linkage
Morgan became interested in how traits were inherited and distributed in developing organisms after noticing a male fruit-fly had white eyes. Morgan chose to do a simple breeding analysis to find out more about white eyes. He was about to confirm the chromosome theory. -
Atomic Model
Bohr expanded on Ruherford's ideas, placing his attention to describe electrons. S simple definition of the atomic model was that electrons orbit the nucleus at set distances. When an electron charges orbits, it does so in a sudden quantum leap. The difference in energy between the first and last orbit is emitted by the atom in bundles of electromagnetic radiation called protons. His model was based on his observations of the atomic emissions spectrum of the hydrogen atom. -
Identifying the transforming principle
Oswald Avery, Maclyn McCarty, and Colin MacLeod set out to identify Griffith's "transforming principle". They started with large cultures of heat-killed S cells and a long series of biochemical steps, progressively purified the transforming principle by washing away, separating out, or enzymatically destroying the other cellular components. They were able to obtain limited amounts of highly purified transforming principle, which they then analyzed through other tests to determine its identity. -
Image 51
After moving back to London in 1951, Rosalind took charge of the lab with her customary efficiency, directing gradute student, Raymond Goslong, in making refinements to the X-Ray equipment. Franklin and Gosling discovered that there was two forms of DNA shown in X-ray images. The dry "A" form and a wetter "B" form. Since each X-ray chromatograph had been exposed for over 100 hours to form an image. Image 51 was the "B" form which appeared to show a helical structure. -
Hershey-Chase experiments
Hershey and Chase studied bacteriophage, or viruses that attack bacteria. Before the experiment, Hershey thought that the genetic material would prove to e protein. To establish whether the phage injected DNA or protein into host bacteria, they prepared two different batches of phage. Each batch phage was produced in the presence of a specific radioactive element. Each batch was used to infect a different culture of bacteria. They concluded that DNA, not protein, was injected into host cells. -
Watson-Crick model of DNA
The deoxyribonucleic acid, known as DNA, is a double stranded helix molecule. It consists of two phosphate backbones held together by hydrogen bonds between nitrogen bases on the inside. Watson and Crick realized that the pairing rules meant that either strand would contain all the information needed to make a copy of the entire molecule. They believed that the order of the bases could provide a genetic code. They won a Nobel prize in 1962 for their discovery, sharing it with Maurice Wilkins. -
Genetic Code
Marshall Nirenberg discovered the first "triplet", a sequence of three bases of DNA that codes for one of the twenty amino acids that serves as the building blocks of proteins. By 1963 he had deciphered 35 codes and over 60 by 1966. Each codon was found to consist of three bases in a specific order. -
Dolly the sheep is cloned
Dolly was cloned at the Roslin Institute in Midlothian, Scotland. Her birth was announced on February 22, 1997 and lived for 6 years. The technique that was made famous by her birth is somatic cell nuclear transfer, in which a cell is placed in a de-nucleated ovum, the two cells then fuse and then develop into an embryo. -
Endosymbiotic Theory
Lynn Margulis' hypothesis originally proposed that the mitochondria was the result of endocytosis of aerobic bacteria, chloroplasts were the results of endocytosis of photosynthetic bacteria; that in both cases by large anaerobic bacteria who would not otherwise be able to exist in an aerobic environment, and that the arrangement became a mutually beneficial relationship for both cells (symbiotic). -
Apollo 11
By July 16, 1969, astronauts Neil Armstrong, Buzz Aldrin, and Michael Collins awaited their Launch at the Kennedy Space Center. It took them the men 3 days to arrive in lunar orbit. A day later, Armstrong and Aldrin enter the lunar module "Eagle", to begin descent. The men landed on the moon at 4:18 pm EDT. Armstrong later plants the first human foot on moon and says, "That's one small step for a man, one giant leap for mankind". -
The Sanger Technique
Fred Sanger devised a method used for determining the sequence of amino acids that make up a specific protein. He successfully identified the sequence of 51 amino acids that make up the insulin molecule. His method of protein analysis has since enabled scientist to determine the structure of many other proteins. The "Sanger Method" was known as the development of the dideoxy technique, used for sequencing DNA molecules. -
Hydrothermal Vent Creatures
Hydrothermal vents are home to dozens of previously known species. Red-tipped warms, ghostly fish, strange shrimp with eyes on their backs and other unique species survive in these extreme deep ocean ecosystems found near undersea volcanic chains. Chemosnthesis, are microbes at the base of the food chain that convert chemicals from vents into usable energy. -
Polymerase Chain Reaction
The PCR is based on using the ability of DNA polymerase to synthesize new strand on DNA complementary to the offered template strand. This is the revolutionary method developed by Kary Mullis in the 1980s. -
CRISPR-CAS9
CRISPr-Cas9 enables genetics and medical researches to edit parts of the genome by removing , adding, or altering sections of the DNA sequence. IT consist of two key models; enzymes, and RNA. The enzymes act as a pair of scissors; that can cut the two strands of DNA at a specific location in the genome so that pieces of the DNA can then be added or removed. RNA consist of a small piece of pre-designed RNA sequences (about 20 bases) located within a longer RNA scaffold. -
Sahelanthropus tchadensis
French paleontologist Michael Brunet uncovered the fossils in 2001 in Africa. They had only been found in the Great Rift Valley in East Africa and sites in South Africa. The Sahelanthropus tchadensis lived between 6 and 7 million years ago in West-Central Africa (Chad). The large opening where the spinal cord exits out of the cranium from the brain is the indication that the head was held on upright on the body.
http://humanorigins.si.edu/evidence/human-fossils/species/sahelanthropus-tchadensis -
Human Genome
The International Human Genome Sequencing released a rough draft of the human genome sequence on June 26, 2000. The difference of the draft and finished versions is defined by the coverage, number of gaps, and the error rate. The genome is defined as an organism's complete set of deoxyribonucleic acid (DNA), the key instructions to develop and direct activities of every organism.
