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330 BCE
Aristotle describes life with the Scala Naturae
Aristotle, a Greek philosopher and polymath, generates the idea of the "Nature Ladder". He claimed the nature world could be arranged in a single continuum. Although he was wrong, it was considered "the greatest biological synthesis of the time". This is where we differentiated animals by vertebrates and invertebrates. Link text -
162 BCE
Galen describes human body
Aelius Galen was a greek physician, surgeon and philosopher. He was very experienced in anatomy, pharmacology, and surgery. He was forced to disscet animals and treat wounded gladiators so he could gain more knowledge about the human body.
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Lamarck develops Hypothesis of evolution
Lamarack believed if an organism changes during its life to adapt to is environment, the changes that are made are passed to their offspring. He believed elephants used to have small trunks, when there was no food or water that had to adapt to live. He believed people would eventually begin to no longer be born with little toes and appendixes.
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The Voyage of the HSM Beagle
A crew of 73 men set sail leaving the Plymouth Harbor, lead by Darwin. The captain was FitzRoy. The purpose of the trip was to chart the coasts of Patagonia and Tierra del Fuego. Darwin recorded observations of plants and animals in countries that European naturalists were unfamiliar with.
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Alfred Russel Wallace published ideas of evolutionary processes
Wallace visited the Galapagos with Darwin. He was a British naturalist, and the co-discoverer of the theory of evolution. They both came to similar assumptions about mankind's origins, and published their theory.
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The Origin of species by means of Natural Selection is published
Charles Darwin published Origin of Species by Means of Natural Selection to explain the theory of evolution. He preformed a few experiments to back his hypothesis. This book was one of the most influential of the time. After returning from his voyages, he published radical scientific studies of zoology, and geology.
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Germ Theory of Disease
This theory states that diseases are caused by microorganisms. They are much to small to see with the naked human eye. Their growth and reproduction can cause disease. Louis Pasteus, Joseph Lister, and Robert Koch are given the credit for this theory.
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Louis Pasteur refutes spontaneous generation
Pasteur set up ab expirament to test sterile nutrient broth could naturally generate microbial life. He used "swan neck" flasks where he boiled broth to sterilize it. The flasks he used allowed the outside and inside air to interact. His prediction was right, and he disproved the theory of spontaneous generation.
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Mendel and inheritance of traits
Mendel grew over 10,000 pea plants labeling the progeny number and type to show the laws of inheritance. Although his work was not appreciated in his time, it helps us understand the way inheritance of genes works. He tracked the similarities and differences offspring has from their parents.
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Plasmodium falciparum described
Plasmodiun falciparum is a protozoan parasite. It is usually found in the blood of a host that has malaria. It is typically transmitted by the female Anopheles mosquito. Charles Louis Alphonse Laveran was the first to discover the parasite in the blood of infected malaria victums -
Neil Bhor develops Bohr model
Bohr and Rutherford published Bohrs model of the atom structure. It claims the small atom, with a positively charged nucleus surrounded by electrons travel in a circular orbit around the nucleus. You can compair it to the solar system.
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Synthetic Theory of Evolution
Dobzhansky published his theory which is a complex array of biological knowledge that is centered around Darwins theory of evolution.
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Ensatina described as a ring species
Robert C. Stebbins studied Salamanders in California to investigate their range. A ring species is when two species do not interbreed, but live in the same region, and are connected by a geographical ring.
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SCUBA
Jacques Cousteau, french oceanograpger, invented scuba diving. The first prototype was called Agualung, and was two tanks of compressed air, a mouth piece, and hoses. Gagnan was his co-inventor. Link text -
Avery, MacLoed and McCarty determine that DNA carries the genetic code
Frederick observed two strains of Step bacteria. The S strain has smooth walls and killed the mice it was tested on. Strain R had rough walls and did not kill the mice.
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Hershey-Chase experiments are published
A.D Hershey and Martha Chase showed that DNA was not a protein, but genetic material. There is a protein protective coat around the bacteriophage, but DNA is what is able to produce progeny.
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Rosalind Franklin works with DNA and X-Ray crystallography
Photograph 51 is the X-ray diffusion image of DNA taken by Raymond Gosling, and studied by Franklin. She almost discovered what DNA's structure was, but barley missed it.
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Miller-Urey experiments published
L. Miller and Harold C. Urey tested the hypothetical conditions present on the early Earth to see what kind of environment would be needed for life to begin.
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Watson and Crick discover the double helix structure
When Crick and Watson made this ground breaking discovery, it changed the rise of modern biology. The well know structure of DNA is recognized as the twisted ladder/double helix. Researches knew that the term gene meant the smallest unit of genetic information, but no one knew what it looked like. Without this understanding, we would not know what heredity and reproductions is.
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Apollo 11
Niel Armstrong and Buzz Aldrin were the first two humans to step foot on a planetary body besides Earth. This was the first successful lunar landing which lead to many more. -
Lucy fossil is discovered
Donald Johnson and Tom Gray came across the remains of an unknown species closely related to an ape fossil. They called the fossil Lucy, and was later classifed as a 3.2 million-year old "Australopitecus afarensis". Lucy was found in Hadar, Ethiopia which was said to be a hot spot for fossils.
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“Reproductive isolation as a consequence of adaptive divergence in Drosophila pseudoobscrura” published
Dianne M. Dodd published this article to give knowledge of reproductive isolation. Eight populations of fruit flies were studied to gain insight of the process. [Link text]https://www.jstor.org/stable/2409365?seq=1#page_scan_tab_contents -
Sahelanthropus tchadensis
A research team of scientists lead by Michael Brunet uncovered nine fossils from Northern Chad.
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Human Genome Sequenced
DNA is the human genome in which determines the exact orders of base pairs. -
Homo denisova fossil discovered
A Chinese/US team finds a 105,000 to 125,000 fossils. They could be a new type of human or an eastern variant of Neandertals.
