Charles Darwin

Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock strata by using the fossil assemblages contained within them. The primary objective of biostratigraphy is correlation, demonstrating that a particular horizon in one geological section represents the same period of time as another horizon at a different section. Fossils within these strata are useful because sediments of the same age can look completely different, due to local variations in the sedimentary environment. For example, one section might have been made up of clays and marls, while another has more chalky limestones. However, if the fossil species recorded are similar, the two sediments are likely to have been laid down around the same time. Ideally these fossils are used to help identify biozones, as they make up the basic biostratigraphy units, and define geological time periods based upon the fossil species found within each section.

Basic concepts of biostratigraphic principles were introduced in the early 1800s. A Danish scientist and bishop by the name of Nicolas Steno was one of the first geologists to recognize that rock layers correlate to the Law of Superposition. With advancements in science and technology, by the 18th century it began to be accepted that fossils were remains left by species that had become extinct, but were then preserved within the rock record. The method was well-established before Charles Darwin explained the mechanism behind it—evolution. Scientists William Smith, George Cuvier, and Alexandre Brongniart came to the conclusion that fossils then indicated a series of chronological events, establishing layers of rock strata as some type of unit, later termed biozone. From here on, scientists began relating the changes in strata and biozones to different geological eras, establishing boundaries and time periods within major faunal changes. By the late 18th century the Cambrian and Carboniferous periods were internationally recognized due to these findings. During the early 20th century, advancements in technology gave scientists the ability to study radioactive decay. Using this methodology, scientists were able to establish geological time, the boundaries of the different eras (Paleozoic, Mesozoic, Cenozoic), as well as Periods (Cambrian, Ordovician, Silurian) through the isotopes found within fossils via radioactive decay. Current 21st century uses of biostratigraphy involve interpretations of age for rock layers, which are primarily used by oil and gas industries for drilling workflows and resource allocations.

Emotions are physical and mental states brought on by neurophysiological changes, variously associated with thoughts, feelings, behavioral responses, and a degree of pleasure or displeasure. There is no scientific consensus on a definition. Emotions are often intertwined with mood, temperament, personality, disposition, or creativity.

Research on emotion has increased over the past two decades, with many fields contributing, including psychology, medicine, history, sociology of emotions, computer science and philosophy. The numerous attempts to explain the origin, function, and other aspects of emotions have fostered intense research on this topic. Theorizing about the evolutionary origin and possible purpose of emotion dates back to Charles Darwin. Current areas of research include the neuroscience of emotion, using tools like PET and fMRI scans to study the affective picture processes in the brain.

Antonio Francesco Gramsci (UK: /ˈɡræmʃi/ GRAM-shee, US: /ˈɡrɑːmʃi/ GRAHM-shee; Italian: [anˈtɔːnjo franˈtʃesko ˈɡramʃi] ; 22 January 1891 – 27 April 1937) was an Italian Marxist philosopher and politician. He was a founding member and one-time leader of the Italian Communist Party. A vocal critic of Benito Mussolini and fascism, he was imprisoned in 1926, and remained in prison until shortly before his death in 1937.

During his imprisonment, Gramsci wrote more than 30 notebooks and 3,000 pages of history and analysis. His Prison Notebooks are considered a highly original contribution to 20th-century political theory. Gramsci drew insights from varying sources—not only other Marxists but also thinkers such as Niccolò Machiavelli, Vilfredo Pareto, Charles Darwin, Sigmund Freud, Friedrich Nietzsche, Pierre Joseph Proudhon, Georges Sorel, and Benedetto Croce. The notebooks cover a wide range of topics, including the history of Italy and Italian nationalism, the French Revolution, fascism, Taylorism and Fordism, civil society, the state, historical materialism, folklore, religion, and high and popular culture.

Disgust (Middle French: desgouster, from Latin gustus, 'taste') is an emotional response of rejection or revulsion to something potentially contagious or something considered offensive, distasteful or unpleasant. In The Expression of the Emotions in Man and Animals, Charles Darwin wrote that disgust is a sensation that refers to something revolting. Disgust is experienced primarily in relation to the sense of taste (either perceived or imagined), and secondarily to anything which causes a similar feeling by sense of smell, touch, or vision. Musically sensitive people may even be disgusted by the cacophony of inharmonious sounds. Research has continually proven a relationship between disgust and anxiety disorders such as arachnophobia, blood-injection-injury type phobias, and contamination fear related obsessive–compulsive disorder (also known as OCD).

Disgust is one of the basic emotions of Robert Plutchik's theory of emotions, and has been studied extensively by Paul Rozin. It invokes a characteristic facial expression, one of Paul Ekman's six universal facial expressions of emotion. Unlike the emotions of fear, anger, and sadness, disgust is associated with a decrease in heart rate (for body-envelope violations) and proto-nausea of the stomach (for bodily effluvia).

Lewis Henry Morgan (November 21, 1818 – December 17, 1881) was an American anthropologist and social theorist, who worked as a railroad lawyer. He is best known for his work on kinship and social structure, his theories of social evolution, and his ethnography of the Iroquois. Interested in what holds societies together, he proposed the concept that the earliest human domestic institution was the matrilineal clan, not the patriarchal family.

Also interested in what leads to social change, he was a contemporary of the European social theorists Karl Marx and Friedrich Engels, who were influenced by reading his work on social structure and material culture, the influence of technology on progress. Morgan is the only American social theorist to be cited by such diverse scholars as Marx, Charles Darwin, and Sigmund Freud. Elected as a member of the National Academy of Sciences, Morgan served as president of the American Association for the Advancement of Science in 1880.

Evolution is the change in the heritable characteristics of biological populations over successive generations. It occurs when evolutionary processes such as genetic drift and natural selection act on genetic variation, resulting in certain characteristics becoming more or less common within a population over successive generations. The process of evolution has given rise to biodiversity at every level of biological organisation.

The scientific theory of evolution by natural selection was conceived independently by two British naturalists, Charles Darwin and Alfred Russel Wallace, in the mid-19th century as an explanation for why organisms are adapted to their physical and biological environments. The theory was first set out in detail in Darwin's book On the Origin of Species. Evolution by natural selection is established by observable facts about living organisms: (1) more offspring are often produced than can possibly survive; (2) traits vary among individuals with respect to their morphology, physiology, and behaviour; (3) different traits confer different rates of survival and reproduction (differential fitness); and (4) traits can be passed from generation to generation (heritability of fitness). In successive generations, members of a population are therefore more likely to be replaced by the offspring of parents with favourable characteristics for that environment.

The domestication of vertebrates is the mutual relationship between vertebrate animals, including birds and mammals, and the humans who influence their care and reproduction.

Charles Darwin recognized a small number of traits that made domesticated species different from their wild ancestors. He was also the first to recognize the difference between conscious selective breeding (i.e. artificial selection) in which humans directly select for desirable traits, and unconscious selection where traits evolve as a by-product of natural selection or from selection of other traits. There is a genetic difference between domestic and wild populations. There is also a genetic difference between the domestication traits that researchers believe to have been essential at the early stages of domestication, and the improvement traits that have appeared since the split between wild and domestic populations. Domestication traits are generally fixed within all domesticates, and were selected during the initial episode of domestication of that animal or plant, whereas improvement traits are present only in a portion of domesticates, though they may be fixed in individual breeds or regional populations.

Paleontology or palaeontology is the scientific study of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geologic time, and assess the interactions between prehistoric organisms and their natural environment. While paleontological observations are known from at least the 6th century BC, the foundation of paleontology as a science dates back to the work of Georges Cuvier in 1796. Cuvier demonstrated evidence for the concept of extinction and how the life of the past was not necessarily the same as that of the present. The field developed rapidly over the course of the following decades, and the French word paléontologie was introduced for the study in 1822, which was derived from the Ancient Greek word for 'ancient' and words describing relatedness and a field of study. Further advances in the field accompanied the work of Charles Darwin who popularized the concept of evolution. Together, evolution and extinction can be understood as complementary processes that shaped the history of life.

Paleontology overlaps the most with the fields of geology and biology. It draws on technology and analysis of a wide range of sciences to apply them to the study of life and environments of the past, particularly for the subdisciplines of paleobiology and paleoecology that are analogous to biology and ecology. Paleontology also contributes to other sciences, being utilized for biostratigraphy to reconstruct the geologic time scale of Earth, or in studies on extinction to establish both external and internal factors that can lead to the disappearance of a species. Much of the history of life is now better understood because of advances in paleontology and the increase in interdisciplinary studies. Several improvements in understanding have occurred from the introduction of theoretical analysis to paleontology in the 1950s and 1960s which led to the rise of more focused fields of paleontology that assess the changing geography and climate of Earth, the phylogenetic relationships between different species, and the analysis of how fossilization occurs and what biases can impact the quality of the fossil record.

"On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection" is the title of a journal article, comprising and resulting from the joint presentation of two scientific papers to the Linnean Society of London on 1 July 1858: On The Tendency of Varieties to Depart Indefinitely from the Original Type by Alfred Russel Wallace and an Extract from an unpublished Work on Species from Charles Darwin's Essay of 1844. The article also includes an Abstract of a Letter from Darwin to Asa Gray, and an introductory letter by Joseph Dalton Hooker and Charles Lyell. The article was the first announcement of the Darwin–Wallace theory of evolution by natural selection; and appeared in print on 20 August 1858. The presentation of the papers spurred Darwin to write a condensed "abstract" of his "big book", Natural Selection. This was published in November 1859 as On the Origin of Species.

Natural Selection is the manuscript in which Charles Darwin drafted his planned species book to publish his theory of natural selection. He had noted his concepts in an 1842 Pencil Sketch and an 1844 Essay. In September 1854 he "began sorting notes for species Theory" in preparation for publication, and in May 1856 began writing his Natural Selection "big book". He was on track to publish sometime between 1859 and 1861, but was interrupted by Wallace sending him a similar concept in 1858, so their essays were read together as papers "On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection". Darwin then wrote an abstract, titled On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, which he published in 1859.

The first two chapters were published in 1868 as The Variation of Animals and Plants Under Domestication.The unpublished eight and a half chapters of Natural Selection were among the manuscripts collated after Darwin's death, and were first transcribed and published in 1975, by Robert C. Stauffer.