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4000 BCE
Plasmodium falciparum is described as the causative agent of malaria
The protozoan Plasmodium falciparum is responsible for causing 500 million cases of malaria per year as well as 100-200 million deaths per year worldwide -
384 BCE
Aristotle describes life with the Scala Naturae
Aristotle was a Greek philosopher and polymath. he was the first to give the first detailed classification of living things, and hence the first systematists. his classification of animals was as follows:
vertebrates ,land mammals
Birds,reptiles and amphibians, Fish, Cetaceans Aristotle's ideas were essentially based on the idea of the scala naturae, the "Natural Ladder" according to which the entire natural world could be arranged in a single continuum -
1546
. The Germ Theory of Disease is published
the germ theory sates many diseases are caused by microorganisms. These small organisms, too small to see without magnification, invade humans, animals, and other living hosts. Their growth and reproduction within their hosts can cause a disease.The germ theory was proposed by Girolamo Fracastoro -
Lamarck develops Hypothesis of evolution by means of acquired characteristics
The inheritance of acquired characteristics is a hypothesis that physiological changes acquired over the life of an organism may be transmitted to offspring. He noticed that fossils in a sequence had grown closer to living species with time. pangenesis theory held that very part of the body emits tiny particles, gemmules, which migrate to the gonads and contribute to the fertilised egg and so to the next generation. The theory implied blending inheritance -
Gregor Mendel publishes works on inheritance of traits in pea plants
Gregor Mendel, through his work on pea plants, discovered the fundamental laws of inheritance. He deduced that genes come in pairs and are inherited as distinct units, one from each parent. Mendel tracked the segregation of parental genes and their appearance in the offspring as dominant or recessive traits. He recognized the mathematical patterns of inheritance from one generation to the next. -
The Voyage of the HMS Beagle
Charles Darwin received an astounding invitation: to join the HMS Beagle as ship's naturalist for a trip around the world. For most of the next five years, the Beagle surveyed the coast of South America, leaving Darwin free to explore the continent and islands, including the Galápagos. He filled dozens of notebooks with careful observations on animals, plants and geology, and collected thousands of specimens, which he crated and sent home for further study. -
Alfred Russel Wallace published ideas of evolutionary processes
Wallace concluded that living things evolve. -
The Origin of species by means of Natural Selection is published
Charles Darwin published On the Origin of Species by Means of Natural Selection. Darwin’s theory argued that organisms gradually evolve through a process he called “natural selection.” In natural selection, organisms with genetic variations that suit their environment tend to propagate more descendants than organisms of the same species that lack the variation, thus influencing the overall genetic makeup of the species. -
Louis Pasteur refutes spontaneous generation
Louis Pasteur designed an experiment to test whether sterile nutrient broth could spontaneously generate microbial life. To do this, he set up two experiments. In both, Pasteur added nutrient broth to flasks, bent the necks of the flasks into S shapes, and then boiled the broth to kill any existing microbes. -
. Watson and Crick propose the double helix model of DNA structure
Watson decide to make new cardboard cutouts of the two bases, to see if perhaps a different atomic configuration would make a difference. It did. Not only did the complementary bases now fit together perfectly (i.e., A with T and C with G), with each pair held together by hydrogen bonds -
The Challenger Oceanography Expedition sails around the world
Modern oceanography began with the Challenger Expedition between 1872 and 1876. It was the first expedition organized specifically to gather data on a wide range of ocean features, including ocean temperatures seawater chemistry, currents, marine life, and the geology of the seafloor.The expedition was led by British naturalist John Murray and Scottish naturalist Charles Wyville Thompson -
T. Hunt Morgan discovers sex-linkage
he first performed a test cross between the white-eyed male fly and several purebred, red-eyed females to see whether white eyes might also occur in the next generation. Morgan first person to definitively link the inheritance of a specific trait with a particular chromosome. -
Neils Bohr develops the Bohr model of atom structure
Bohr atomic model, description of the structure of atoms, especially that of hydrogen, proposed by the Danish physicist Niels Bohr. Atoms absorb or emit radiation only when the electrons abruptly jump between allowed, or stationary, states. -
Barbara McClintock describes transposons
the Discovery of Jumping Genes. first scientist to correctly speculate on the basic concept of epigenetics-or heritable changes in gene expression that are not caused by changes to DNA sequences. -
Theodosius Dobzhansky publishes Genetics and the Origin of Species
Genetics and the Origin of Species is a 1937 book by the Ukrainian-American evolutionary biologist Theodosius Dobzhansky. Dobzhansky applied the theoretical work of Sewall Wright (1889-1988) to the study of natural populations, allowing him to address evolutionary problems -
Beadle and Tatum publish the 1 gene-1 enzyme hypothesis
George Wells Beadle is the theory that each gene directly produces a single enzyme, which consequently affects an individual step in a metabolic pathway. Beadle demonstrated that one gene in a fruit fly controlled a single, specific chemical reaction in the fruit fly, which one enzyme controlled. -
Jacques Cousteau develops SCUBA
Thanks to Jacques Cousteau and his partner Emilie Gagnan, divers were finally able to explore parts of the ocean they had never seen before. In 1942, Cousteau and Gagnan co-invented a demand valve system that would supply divers with compressed air when they breathed. This modern demand regulator was named Aqua-Lung -
Avery, MacLoed and McCarty determine that DNA is the molecule that carries the genetic code
Oswald Avery, Colin MacLeod and Maclyn McCarty helped demonstrate the role of DNA as the carrier of genetic information by working with the bacterium that causes pneumonia , Streptococcus, and pneumoniae. -
The first atomic bomb is used in war
during World War II (1939-45), an American B-29 bomber dropped the world’s first deployed atomic bomb over the Japanese city of Hiroshima -
Ensatina described as a ring species
Since species are often defined by their inability to interbreed with other species, Ensatina seemed to represent the whole process of speciation all the gradual changes that accumulate in two lineages and that wind up making them incompatible with one another. -
Hershey-Chase experiments are published
The Hershey–Chase experiments were a series of experiments conducted in 1952[1] by Alfred Hershey and Martha Chase that helped to confirm that DNA is genetic material.In their experiments, Hershey and Chase showed that when bacteriophages, which are composed of DNA and protein, infect bacteria, their DNA enters the host bacterial cell, but most of their protein does not. -
Miller-Urey experiments published
The Miller–Urey experiment[1] (or Miller experiment)[2] was a chemical experiment that simulated the conditions thought at the time to be present on the early Earth, and tested the chemical origin of life under those conditions. The experiments showed that simple organic compounds of building blocks of proteins and other macromolecules can be formed from gases with the addition of energy. -
Rosalind Franklin works with DNA and X-Ray crystallography and develops “Image 51”
Photograph 51 is the nickname given to an X-ray diffraction image of crystallized DNA taken by Raymond Gosling -
Nirenberg cracks the genetic code
In 1953 James Watson and Francis Crick revealed the structure and properties of DNA, the molecule that carries our genetic information. What they discovered was that the blueprint for a human being was encapsulated in a long string of nucleic acid, arranged in a double helix, like a twisted rope ladder with three billion rungs. -
Meselson and Stahl work with DNA replication
The Meselson–Stahl experiment is an experiment by Matthew Meselson and Franklin Stahl that supported Watson and Crick's hypothesis that DNA replication was semiconservative. 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 -
Endosymbiosis is described by Lynn Margulis
Evolutionist Lynn Margulis showed that a major organizational event in the history of life probably involved the merging of two or more lineages through symbiosis. she studied the structure of cells -
Apollo 11 lands on the moon
President Kennedy's challenge was to put a man on the moon.July 16, Apollo 11 astronauts Neil Armstrong, Buzz Aldrin and Michael Collins sit atop another Saturn V at Launch Complex 39A at the Kennedy Space Center.They leave behind an American flag, a patch honoring the fallen Apollo 1 crew, and a plaque on one of Eagle's legs. -
Australopithicus afarensis nicknamed “lucy” fossil discovered
Australopithecus means ‘southern ape’ and was originally developed for a species found in South Africa.‘Lucy’AL 288-1 is a partial skeleton discovered in 1974 by Donald Johanson in Hadar, Ethiopia. This relatively complete female skeleton, dated to 3.2 million years old, is the most famous individual from this species. she could walk on two legs -
Deep sea hydrothermal vents and associated life around them are discovered
The scientists had made a fascinating discovery the deep-sea hydrothermal vents. They also realized that an entirely unique ecosystem, including hundreds of new species, existed around the vents. Despite the extreme temperatures and pressures, toxic minerals, and lack of sunlight that characterized the deep-sea vent ecosystem, the species living there were thriving -
Galen of Pergamon describes the human body
Galen regarded anatomy as the foundation of medical knowledge,He distinguished seven pairs of cranial nerves, described the valves of the heart, and observed the structural differences between arteries and veins. One of his most important demonstrations was that the arteries carried blood -
Kary Mullis develops Polymerase Chain Reaction
The Polymerase Chain Reaction technique, invented in 1985 by Kary B. Mullis, allowed scientists to make millions of copies of a scarce sample of DNA. -
Tommie Lee Andrews is convicted of rape
An expert in genetics analysis had testified that the DNA ''fingerprint'' of Tommy Lee Andrews' blood matched that of the rapist's semen.The experts testified that the DNA tests provide the same certainty of identification as do fingerprints.DNA, deoxyribonucleic acid, is the substance that makes up chromosomes and carries the genetic code determining personal characteristics such as eye color and hair texture. -
Richard L Bible is executed
Bible was released from prison after serving a sentence imposed in 1981 for kidnapping and sexual he killed Jennifer Wilson . In one of the first DNA cases, blood smeared on a shirt and worn by Bible at his arrest was tested and found to be the blood of Jennifer. -
“Reproductive isolation as a consequence of adaptive divergence in Drosophila pseudoobscrur a” published
speciation is a problem of reproduction isolation. mating is prevented from occurring, and post mating isolation. mating will take place but offspring are not produced. -
The Innocence Project is founded
The Innocence Project is a non-profit legal organization that is committed to exonerating wrongly convicted people through the use of DNA testing and to reforming the criminal justice system to prevent future injustice. the Innocence Project has led to the freeing of more than 350 wrongfully convicted people based on DNA, including 20 who spent time on death row, and the finding of 150 real perpetrators. -
Dolly the sheep is cloned
Dolly was part of an experiment were they wanted to develop a better method for producing genetically modified livestock.Dolly was cloned from a cell taken from the mammary gland of a six-year-old Finn Dorset sheep and an egg cell taken from a Scottish Blackface sheep. She was born to her Scottish Blackface surrogate mother Dolly’s white face was one of the first signs that she was a clone because if she was genetically related to her surrogate mother, she would have had a black face. -
Deep sea hydrothermal vents and associated life around them are discovered
The scientists had made a fascinating discovery the deep-sea hydrothermal vents. They also realized that an entirely unique ecosystem, including hundreds of new species, existed around the vents. Despite the extreme temperatures and pressures, toxic minerals, and lack of sunlight that characterized the deep-sea vent ecosystem, the species living there were thriving -
Spliceosomes were discovered and described
A spliceosome is a large and complex molecular machine found primarily within the splicing speckles of the cell nucleus of eukaryotic cells. The spliceosome is assembled from snRNAs and SR protein. The spliceosome removes introns from a transcribed pre-mRNA, a type of primary transcript. This process is generally referred to as splicing.Only eukaryotes have spliceosomes and some organisms have a second spliceosome, the minor spliceosome. -
Hardy and Weinberg independently develop the Hardy-Weinberg equation for determining allele frequencies in populations
The Hardy-Weinberg equilibrium is the fundamental concept in population genetics the study of genetics in a defined group. A significant implication of the Hardy-Weinberg relationship is that the frequency of the dominant and recessive alleles will remain unchanged from one generation to the next, given certain conditions -
Sahelanthropus tchadensis fossil discovered
Sahelanthropus tchadensis is one of the oldest known species in the human family tree. 7 and 6 million years ago in West-Central Africa. this species had a combination of ape-like and human-like features. This skull is evidence that species had a small brain and a sloping face, like a chimpanzee. The size of the skull suggests the individual was a male. His small, flat canine teeth are unusual for a male primate -- one of the first unique human traits. -
Human genome is fully sequenced
In 2004, the genome project reported that there were 341 gaps in the sequence. Most of the gaps 250 are in the main part of each chromosome, where genes make the proteins that life runs on. These gaps are tiny. Only a few gaps 33 at last count lie in or near each chromosome’s centromere and telomeres but these 33 are 10 times as long in total as the 250 gaps. -
Homo denisova fossil discovered
the extinct ice age humans called Denisovans have been known only from bits of DNA, taken from a sliver of bone in the Denisova Cave in Siberia, Russia. Now, two partial skulls from eastern China are emerging as prime candidates for showing what these shadowy people may have looked like. -
The Sanger Technique is developed
Sanger sequencing is the process of selective incorporation of chain-terminating dideoxynucleotides by DNA polymerase during in vitro DNA replication. it is the most widely used method for the detection of SNVs. Because both alleles of an autosomal locus are sequenced concurrently and are displayed as an analogue electropherograms, Sanger sequencing is unable to detect mosaic alleles below a threshold of 15–20% and can miss a significant proportion of low-level mosaic mutations -
CRISPr/CAS 9 is identified and described
CRISPR-Cas9 is a unique technology that enables geneticists and medical researchers to edit parts of the genome by removing, adding or altering sections of the DNA sequence.
