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Charles Darwin was born
Charles Robert Darwin was born on February 12, 1809 in Shrewsbury, Shropshire. He was born into a wealthy and influential family. His maternal grandfather, Josiah Wedgwood, was a china manufacturer and his paternal grandfather, Erasmus Darwin, was one of the leading English intellectuals of his time. -
Jean-Baptiste Lamarck publishes "Philosophie Zoologique"
In "Philosophie Zoologique" Lamarck offers an early explanation to evolution. His theory included the law of use and disuse & the law of inheritance and acquired characteristics. Unlike Darwin, Lamarck believed that species improved from simple life forms to complex life forms. He argued that organisms changed their characteristics in order to better adapt to their environment. This changed behavior would change their physiological makeup and this would carry on to their offspring. -
Charles Lyell publishes "Principles of Geology"
Lyell's theory on how the earth formed was initially seen as shocking to people who supported the Christian belief that the earth formed as a result of supernatural disasters (i.e. Noah's flood). Lyell argued that the formation of the Earth's crust took place through many changes that occurred over a vast period of time. This "uniformitarian" proposal was that the forces controlling the planet today have been operating continuously throughout all of time. -
Darwin and Wallace present their theories on evolution
Soon after Darwin came up with his theories on evolution, he received a letter from an English naturalist named Alfred Wallace. Wallace had conducted similar studies in the Malay Archipelago and had come up with an explanation of natural selection almost identical to Darwin's. Much to Darwin's dismay, he accepted his research and the two men presented their ideas to the Linnaean Society of London in 1858. They were both considered co-founders of the theory of evolution. -
Darwin publishes "The Origin of Species"
In "The Origin of Species", Darwin explores the mechanisms of evolution. His theory is based on three main ideas. First, he states that species are not immutable, they constantly change over time. Second, divergent species share a common ancestor. Third, the mechanism that produces change in species is natural selection. The data needed to back up his points was collected mostly during his voyage on the HMS Beagle, where he observed species of finches on the Galapagos Islands. -
Gregor Mendel publishes "Experiments on Plant Hybrids"
Gregor Mendel, also known as the "father of modern genetics", was an Austrian monk that contributed to the study of genetic inheritance. For years, he conducted experiments on pea plants. He presented his conclusions in two separate lectures for the Natural Science Society in Brunn. The next year, his findings were published in a paper called "Experiments on Plant Hybrids." -
Cambrian Explosion (*actual date is 50 million years ago)
Following the Pre-Cambrian era of evolutionary history, the Camprian Explosion occur. During this time, the world diversified at a rapid rate. Simple ocean life began to develop into multicellular organisms. This phenomenon is an example of adaptive radiation, a process in which organisms diversify into new forms, particularly when a change in environment makes new resources available, creates new challenges and opens new environmental niches. Adaptive radiation is a concept of macroevolution. -
Morgan begins studies on fruit flies
Thomas Hunt Morgan spent 24 years in Columbia University. During that time, he conducted experiments on Drosophilia fruit flies. From his studies, he was able to make significant conclusions involving the role of chromosomes in inheritance. He was able to elaborate on Mendel's genetic studies by pinpointing the precise behavior and exact placement of genes. His studies are summed up in his 1915 book, "Mechanism of Mendelian Heredity". -
Franklin discovers DNA structure
Rosalind Franklin can arguably be called one of the main discoverers of the structure of DNA. Franklin was a scientist at King's College who specialized in x-ray chromotography. As a woman, she had a hard time getting recognized for her work. In the late 1900s, Franklin confirmed the structure of DNA with Photo 51, a picture that showed the distinctly separate strands of DNA. This photo was rumored to have been stolen by Maurice Wilkins (who worked with Franklin) who gave it to Watson and Crick. -
Watson and Crick discover "double helix" structure of DNA
James Watson and Frances Crick, scientists at Cambridge University, published their paper on their research on DNA. In this paper, they elaborated on the "double helix" structure of DNA and the technicalities of DNA replication. Watson published his findings again in his 1968 book, "The Double-Helix". Watson and Crick received the Nobel Prize in 1962. -
Emile Zuckerkandl and Linus Pauling publishes molecular clock hypothesis
The molecular clock hypothesis states that the rate of evolutionary change of any specified protein was approximately constant over time and over different lineages. This was discovered by Zuckerkandl and Pauling when they observed that the number of amino acid differences in hemoglobin between different lineages changed linearly with time, according to fossil evidence. Their findings were used later in the works of Motoo Kimura, who developed the neutral theory of molecular evolution. -
Kimura postulates the neutral theory of molecular evolution
Motoo Kimura, published the neutral theory of molecular evolution, which states that most of the variability in molecular structure does not affect the molecule's functionality. Instead, most of the variability occurs outside of the functional regions of the molecule. These neutral molecules form the basis of molecular clocks and must 1) be present in all of the organisms being studied and 2) must be under functional constraints. An example is rRNA which performs protein synthesis. -
Paleontologists find fossils of ambulocetus natans
The ambulocetus natans ("swimming-walking whale") is an excellent representation of one of Darwin's main principles: that all organisms come from a common ancestor. Paleontologists confirmed this fact when they found the remains of a now-extinct species that is believed to be the distant relative of the whale. This is also an example of molecular biology; mutations in the genetic makeup of the ambulocetus natans gradually resulted in the whale that we are all familiar with today. -
B-15A iceberg separates penguins colonies
In 2001 and in years preceding that, scientists have been intently observing colonies of Adelie penguins in Antarctica. Often, massive icebergs break away from the mainland and disrupt the behavioral patterns of the penguins. For example, fathers who go out to get food may not be able to return to their colonies. As a result, genetic characteristics unique to one colony could potentially spread to other colonies. This phenomenon is called microevolution. -
Scientists publish the Human Genome Project
The history of the Human Genome Project begins in 1911 when researcher Alfred Sturtevant mapped the location of fruit fly genes. From there, scientists of the International Human Genome Sequencing Consortium worked to map the genes of humans. In the first publication of the human genome in February 2001, approximately 90% of the 3 billion base pairs were mapped. Following its completion in 2003, scientists predicted that there were approximately 20,500 genes in the human genome. -
Peter and Rosemary Grant publish "How and Why Species Multiply"
Peter and Rosemary Grant dedicated many years to studying "Darwin's finches" on an island called Daphne Major and exploring the concept of speciation. In their studies, they closely observed the effect of an immigrant hybrid species of the two species that were already on the island (the cactus finch and ground finch). Over the years, the couple discovered that the descendants of this immigrant cactus-ground finch mated exclusively with each other, exemplifying sympatric speciation. -
Masatoshi Nei publishes "Mutation-Driven Evolution"
Masatoshi Nei, Japanese biologist and author of "Mutation-Driven Evolution", postulated that mutations, not natural selection, are the driving force of evolution. He explains that molecular change is the real mechanism of evolution. That molecular change in DNA is the definition of a mutation (i.e. insertions). According to Nei, mutations trigger the operation of natural selection. As a result, no evolution can occur without that initial mutation. -
Schopf discovers organism that hasn't evolved in more than 2 billion years
William Schopf, a professor of earth, planetary, and space sciences at UCLA, claims to have discovered an organism that hasn't evolved in more than 2 billion years. This lack of evolution was found in sulfur bacteria. The bacteria is located in the coasts of Chile. Contrary to initial belief, this lack of evolution supports Darwin's theory of evolution. Schopf's studies state that the lack of evolution in the sulfur bacteria is a reflection of the lack of change in the surrounding environment. -
Temple University publishes Time Tree of Life
Recently, researchers at Temple University published the most up-to-date, elaborate depiction of the evolution of life. The tree of life is designed similar to a galaxy and includes approximately 50,000 species. From this new diagram, it has been discovered that life has been expanding at a constant rate. According to professor Blair Hedges, this discovery means that "the ecological niches of life are not being filled up and saturated."
