1.
Evolution
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Evolution is change in the heritable characteristics of biological populations over successive generations. Evolutionary processes give rise to biodiversity at every level of organisation, including the levels of species, individual organisms. In July 2016, scientists reported identifying a set of 355 genes from the LUCA of all living on Earth. The fossil record includes a progression from early biogenic graphite, to microbial mat fossils, existing patterns of biodiversity have been shaped both by speciation and by extinction. More than 99 percent of all species that lived on Earth are estimated to be extinct. Estimates of Earths current species range from 10 to 14 million, more recently, in May 2016, scientists reported that 1 trillion species are estimated to be on Earth currently with only one-thousandth of one percent described. In the mid-19th century, Charles Darwin formulated the theory of evolution by natural selection. This teleonomy is the quality whereby the process of natural selection creates and preserves traits that are fitted for the functional roles they perform. The processes by which the changes occur, from one generation to another, are called evolutionary processes or mechanisms, the four most widely recognized evolutionary processes are natural selection, genetic drift, mutation and gene migration. Natural selection and genetic drift sort variation, mutation and gene migration create variation, consequences of selection can include meiotic drive, nonrandom mating and genetic hitchhiking. In the early 20th century the modern evolutionary synthesis integrated classical genetics with Darwins theory of evolution by natural selection through the discipline of population genetics, the importance of natural selection as a cause of evolution was accepted into other branches of biology. Moreover, previously held notions about evolution, such as orthogenesis, evolutionism, evolutionary computation, a sub-field of artificial intelligence, involves the application of Darwinian principles to problems in computer science. The proposal that one type of organism could descend from another type goes back to some of the first pre-Socratic Greek philosophers, such as Anaximander, such proposals survived into Roman times. The poet and philosopher Lucretius followed Empedocles in his masterwork De rerum natura, in contrast to these materialistic views, Aristotelianism considered all natural things as actualisations of fixed natural possibilities, known as forms. This was part of a teleological understanding of nature in which all things have an intended role to play in a divine cosmic order. In the 17th century, the new method of modern science rejected the Aristotelian approach, however, this new approach was slow to take root in the biological sciences, the last bastion of the concept of fixed natural types. The biological classification introduced by Carl Linnaeus in 1735 explicitly recognized the nature of species relationships. Other naturalists of this time speculated on the change of species over time according to natural laws
2.
Taxonomy (biology)
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Taxonomy is the science of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups. The exact definition of taxonomy varies from source to source, but the core of the remains, the conception, naming. There is some disagreement as to whether biological nomenclature is considered a part of taxonomy, the broadest meaning of taxonomy is used here. The word taxonomy was introduced in 1813 by Candolle, in his Théorie élémentaire de la botanique, the term alpha taxonomy is primarily used today to refer to the discipline of finding, describing, and naming taxa, particularly species. In earlier literature, the term had a different meaning, referring to morphological taxonomy, ideals can, it may be said, never be completely realized. They have, however, a value of acting as permanent stimulants. Some of us please ourselves by thinking we are now groping in a beta taxonomy, turrill thus explicitly excludes from alpha taxonomy various areas of study that he includes within taxonomy as a whole, such as ecology, physiology, genetics, and cytology. He further excludes phylogenetic reconstruction from alpha taxonomy, thus, Ernst Mayr in 1968 defined beta taxonomy as the classification of ranks higher than species. This activity is what the term denotes, it is also referred to as beta taxonomy. How species should be defined in a group of organisms gives rise to practical and theoretical problems that are referred to as the species problem. The scientific work of deciding how to define species has been called microtaxonomy, by extension, macrotaxonomy is the study of groups at higher taxonomic ranks, from subgenus and above only, than species. While some descriptions of taxonomic history attempt to date taxonomy to ancient civilizations, earlier works were primarily descriptive, and focused on plants that were useful in agriculture or medicine. There are a number of stages in scientific thinking. Early taxonomy was based on criteria, the so-called artificial systems. Later came systems based on a complete consideration of the characteristics of taxa, referred to as natural systems, such as those of de Jussieu, de Candolle and Bentham. The publication of Charles Darwins Origin of Species led to new ways of thinking about classification based on evolutionary relationships and this was the concept of phyletic systems, from 1883 onwards. This approach was typified by those of Eichler and Engler, the advent of molecular genetics and statistical methodology allowed the creation of the modern era of phylogenetic systems based on cladistics, rather than morphology alone. Taxonomy has been called the worlds oldest profession, and naming and classifying our surroundings has likely been taking place as long as mankind has been able to communicate
3.
Species
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In biology, a species is the basic unit of biological classification and a taxonomic rank. A species is defined as the largest group of organisms in which two individuals can produce fertile offspring, typically by sexual reproduction. While this definition is often adequate, looked at more closely it is problematic, for example, with hybridisation, in a species complex of hundreds of similar microspecies, or in a ring species, the boundaries between closely related species become unclear. Other ways of defining species include similarity of DNA, morphology, all species are given a two-part name, a binomial. The first part of a binomial is the genus to which the species belongs, the second part is called the specific name or the specific epithet. For example, Boa constrictor is one of four species of the Boa genus, Species were seen from the time of Aristotle until the 18th century as fixed kinds that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped that species could evolve given sufficient time, Charles Darwins 1859 book The Origin of Species explained how species could arise by natural selection. Genes can sometimes be exchanged between species by horizontal transfer, and species may become extinct for a variety of reasons. In his biology, Aristotle used the term γένος to mean a kind, such as a bird or fish, a kind was distinguished by its attributes, for instance, a bird has feathers, a beak, wings, a hard-shelled egg, and warm blood. A form was distinguished by being shared by all its members, Aristotle believed all kinds and forms to be distinct and unchanging. His approach remained influential until the Renaissance, when observers in the Early Modern period began to develop systems of organization for living things, they placed each kind of animal or plant into a context. Many of these early delineation schemes would now be considered whimsical, animals likewise that differ specifically preserve their distinct species permanently, one species never springs from the seed of another nor vice versa. In the 18th century, the Swedish scientist Carl Linnaeus classified organisms according to shared physical characteristics and he established the idea of a taxonomic hierarchy of classification based upon observable characteristics and intended to reflect natural relationships. At the time, however, it was widely believed that there was no organic connection between species, no matter how similar they appeared. However, whether or not it was supposed to be fixed, by the 19th century, naturalists understood that species could change form over time, and that the history of the planet provided enough time for major changes. Jean-Baptiste Lamarck, in his 1809 Zoological Philosophy, described the transmutation of species, proposing that a species could change over time, in 1859, Charles Darwin and Alfred Russel Wallace provided a compelling account of evolution and the formation of new species. Darwin argued that it was populations that evolved, not individuals and this required a new definition of species. Darwin concluded that species are what appear to be, ideas
4.
Jean-Baptiste Lamarck
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Jean-Baptiste Pierre Antoine de Monet, Chevalier de Lamarck, often known simply as Lamarck, was a French naturalist. He was a soldier, biologist, academic, and a proponent of the idea that evolution occurred and proceeded in accordance with natural laws. He gave the term biology a broader meaning by coining the term for special sciences, chemistry, meteorology, geology, Lamarck fought in the Pomeranian War with Prussia, and was awarded a commission for bravery on the battlefield. At his post in Monaco, Lamarck became interested in natural history and he retired from the army after being injured in 1766, and returned to his medical studies. Lamarck developed a particular interest in botany, and later, after he published the three-volume work Flore françoise, Lamarck became involved in the Jardin des Plantes and was appointed to the Chair of Botany in 1788. When the Muséum national dHistoire naturelle was founded in 1793, Lamarck was appointed as a professor of zoology, in 1801, he published Système des animaux sans vertèbres, a major work on the classification of invertebrates, a term he coined. In an 1802 publication, he one of the first to use the term biology in its modern sense. Lamarck continued his work as an authority on invertebrate zoology. He is remembered, at least in malacology, as a taxonomist of considerable stature, however, his idea of soft inheritance was, perhaps, a reflection of the wisdom of the time accepted by many natural historians. Scientists have debated whether advances in the field of transgenerational epigenetics mean that Lamarck was to an extent correct, jean-Baptiste Lamarck was born in Bazentin, Picardy, northern France, as the eleventh child in an impoverished aristocratic family. Male members of the Lamarck family had served in the French army. Lamarcks eldest brother was killed in combat at the Siege of Bergen op Zoom, yielding to the wishes of his father, Lamarck enrolled in a Jesuit college in Amiens in the late 1750s. After his father died in 1760, Lamarck bought himself a horse, and rode across the country to join the French army, Lamarck showed great physical courage on the battlefield in the Pomeranian War with Prussia, and he was even nominated for the lieutenancy. Lamarcks company was exposed to the direct artillery fire of their enemies. When their colonel reached the remains of their company, this display of courage, however, when one of his comrades playfully lifted him by the head, he sustained an inflammation in the lymphatic glands of the neck, and he was sent to Paris to receive treatment. He underwent an operation, and continued his treatment for a year. He was awarded a commission and settled at his post in Monaco and it was there that he encountered Traité des plantes usuelles, a botany book by James Francis Chomel. With a reduced pension of only 400 francs a year, Lamarck resolved to pursue a profession and he attempted to study medicine, and supported himself by working in a bank office
5.
Animal
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Animals are multicellular, eukaryotic organisms of the kingdom Animalia. The animal kingdom emerged as a clade within Apoikozoa as the group to the choanoflagellates. Animals are motile, meaning they can move spontaneously and independently at some point in their lives and their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later in their lives. All animals are heterotrophs, they must ingest other organisms or their products for sustenance, most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago. Animals can be divided broadly into vertebrates and invertebrates, vertebrates have a backbone or spine, and amount to less than five percent of all described animal species. They include fish, amphibians, reptiles, birds and mammals, the remaining animals are the invertebrates, which lack a backbone. These include molluscs, arthropods, annelids, nematodes, flatworms, cnidarians, ctenophores, the study of animals is called zoology. The word animal comes from the Latin animalis, meaning having breath, the biological definition of the word refers to all members of the kingdom Animalia, encompassing creatures as diverse as sponges, jellyfish, insects, and humans. Aristotle divided the world between animals and plants, and this was followed by Carl Linnaeus, in the first hierarchical classification. In Linnaeuss original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, in 1874, Ernst Haeckel divided the animal kingdom into two subkingdoms, Metazoa and Protozoa. The protozoa were later moved to the kingdom Protista, leaving only the metazoa, thus Metazoa is now considered a synonym of Animalia. Animals have several characteristics that set apart from other living things. Animals are eukaryotic and multicellular, which separates them from bacteria and they are heterotrophic, generally digesting food in an internal chamber, which separates them from plants and algae. They are also distinguished from plants, algae, and fungi by lacking cell walls. All animals are motile, if only at life stages. In most animals, embryos pass through a stage, which is a characteristic exclusive to animals. With a few exceptions, most notably the sponges and Placozoa and these include muscles, which are able to contract and control locomotion, and nerve tissues, which send and process signals
6.
Plant
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Plants are mainly multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. The term is generally limited to the green plants, which form an unranked clade Viridiplantae. This includes the plants, conifers and other gymnosperms, ferns, clubmosses, hornworts, liverworts, mosses and the green algae. Green plants have cell walls containing cellulose and obtain most of their energy from sunlight via photosynthesis by primary chloroplasts and their chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic and have lost the ability to produce amounts of chlorophyll or to photosynthesize. Plants are characterized by sexual reproduction and alternation of generations, although reproduction is also common. There are about 300–315 thousand species of plants, of which the great majority, green plants provide most of the worlds molecular oxygen and are the basis of most of Earths ecologies, especially on land. Plants that produce grains, fruits and vegetables form humankinds basic foodstuffs, Plants play many roles in culture. They are used as ornaments and, until recently and in variety, they have served as the source of most medicines. The scientific study of plants is known as botany, a branch of biology, Plants are one of the two groups into which all living things were traditionally divided, the other is animals. The division goes back at least as far as Aristotle, who distinguished between plants, which generally do not move, and animals, which often are mobile to catch their food. Much later, when Linnaeus created the basis of the system of scientific classification. Since then, it has become clear that the plant kingdom as originally defined included several unrelated groups, however, these organisms are still often considered plants, particularly in popular contexts. When the name Plantae or plant is applied to a group of organisms or taxon. The evolutionary history of plants is not yet settled. Those which have been called plants are in bold, the way in which the groups of green algae are combined and named varies considerably between authors. Algae comprise several different groups of organisms which produce energy through photosynthesis, most conspicuous among the algae are the seaweeds, multicellular algae that may roughly resemble land plants, but are classified among the brown, red and green algae. Each of these groups also includes various microscopic and single-celled organisms
7.
Charles Darwin
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Charles Robert Darwin, FRS FRGS FLS FZS was an English naturalist, geologist and biologist, best known for his contributions to the science of evolution. Darwin published his theory of evolution with compelling evidence in his 1859 book On the Origin of Species, by the 1870s, the scientific community and much of the general public had accepted evolution as a fact. In modified form, Darwins scientific discovery is the theory of the life sciences. Darwins early interest in nature led him to neglect his education at the University of Edinburgh, instead. Studies at the University of Cambridge encouraged his passion for natural science, puzzled by the geographical distribution of wildlife and fossils he collected on the voyage, Darwin began detailed investigations and in 1838 conceived his theory of natural selection. Although he discussed his ideas with several naturalists, he needed time for extensive research and he was writing up his theory in 1858 when Alfred Russel Wallace sent him an essay that described the same idea, prompting immediate joint publication of both of their theories. Darwins work established evolutionary descent with modification as the dominant scientific explanation of diversification in nature, in 1871 he examined human evolution and sexual selection in The Descent of Man, and Selection in Relation to Sex, followed by The Expression of the Emotions in Man and Animals. His research on plants was published in a series of books, Darwin has been described as one of the most influential figures in human history, and he was honoured by burial in Westminster Abbey. Charles Robert Darwin was born in Shrewsbury, Shropshire, on 12 February 1809, at his familys home and he was the fifth of six children of wealthy society doctor and financier Robert Darwin and Susannah Darwin. He was the grandson of two prominent abolitionists, Erasmus Darwin on his fathers side, and Josiah Wedgwood on his mothers side, both families were largely Unitarian, though the Wedgwoods were adopting Anglicanism. The eight-year-old Charles already had a taste for history and collecting when he joined the day school run by its preacher in 1817. From September 1818, he joined his older brother Erasmus attending the nearby Anglican Shrewsbury School as a boarder and he found lectures dull and surgery distressing, so neglected his studies. He learned taxidermy in around 40 daily hour-long sessions from John Edmonstone, one day, Grant praised Lamarcks evolutionary ideas. Darwin was astonished by Grants audacity, but had recently read similar ideas in his grandfather Erasmus journals, Darwin was rather bored by Robert Jamesons natural-history course, which covered geology - including the debate between Neptunism and Plutonism. He learned the classification of plants, and assisted with work on the collections of the University Museum, as Darwin was unqualified for the Tripos, he joined the ordinary degree course in January 1828. He preferred riding and shooting to studying, when his own exams drew near, Darwin focused on his studies and was delighted by the language and logic of William Paleys Evidences of Christianity. In his final examination in January 1831 Darwin did well, coming out of 178 candidates for the ordinary degree. Darwin had to stay at Cambridge until June 1831, inspired with a burning zeal to contribute, Darwin planned to visit Tenerife with some classmates after graduation to study natural history in the tropics
8.
On the Origin of Species
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On the Origin of Species, published on 24 November 1859, is a work of scientific literature by Charles Darwin which is considered to be the foundation of evolutionary biology. Darwins book introduced the theory that populations evolve over the course of generations through a process of natural selection. It presented a body of evidence that the diversity of life arose by common descent through a pattern of evolution. Darwin included evidence that he had gathered on the Beagle expedition in the 1830s and his subsequent findings from research, correspondence, various evolutionary ideas had already been proposed to explain new findings in biology. The political and theological implications were intensely debated, but transmutation was not accepted by the scientific mainstream, the book was written for non-specialist readers and attracted widespread interest upon its publication. As Darwin was an eminent scientist, his findings were taken seriously and the evidence he presented generated scientific, philosophical, and religious discussion. The debate over the book contributed to the campaign by T. H. Huxley, during the eclipse of Darwinism from the 1880s to the 1930s, various other mechanisms of evolution were given more credit. Despite periodic fluctuations, populations remain roughly the same size, resources such as food are limited and are relatively stable over time. Individuals in a population significantly from one another. Much of this variation is heritable and this slowly effected process results in populations changing to adapt to their environments, and ultimately, these variations accumulate over time to form new species. In later editions of the book, Darwin traced evolutionary ideas as far back as Aristotle, Nature was widely believed to be unstable and capricious, with monstrous births from union between species, and spontaneous generation of life. After the turmoil of the English Civil War, the Royal Society wanted to show that science did not threaten religious, in Gods benevolent design, carnivores caused mercifully swift death, but the suffering caused by parasitism was a puzzling problem. The biological classification introduced by Carl Linnaeus in 1735 also viewed species as fixed according to the divine plan. In 1766, Georges Buffon suggested that some species, such as horses and asses, or lions, tigers. The Ussher chronology of the 1650s had calculated creation at 4004 BC, wernerians thought strata were deposits from shrinking seas, but James Hutton proposed a self-maintaining infinite cycle, anticipating uniformitarianism. Charles Darwins grandfather Erasmus Darwin outlined a hypothesis of transmutation of species in the 1790s and this process was later called Lamarckism. Lamarck thought there was an inherent progressive tendency driving organisms continuously towards greater complexity, in parallel, Georges Cuvier strongly disputed such ideas, holding that unrelated, fixed species showed similarities that reflected a design for functional needs. His palæontological work in the 1790s had established the reality of extinction, in Britain, William Paleys Natural Theology saw adaptation as evidence of beneficial design by the Creator acting through natural laws
9.
Thomas Henry Huxley
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Thomas Henry Huxley PC PRS FLS was an English biologist, known as Darwins Bulldog for his advocacy of Charles Darwins theory of evolution. Huxleys famous debate in 1860 with Samuel Wilberforce was a key moment in the acceptance of evolution. Huxley had been planning to leave Oxford on the day, but, after an encounter with Robert Chambers. Wilberforce was coached by Richard Owen, against whom Huxley also debated about whether humans were closely related to apes. Huxley was slow to accept some of Darwins ideas, such as gradualism, and was undecided about natural selection, instrumental in developing scientific education in Britain, he fought against the more extreme versions of religious tradition. Originally coining the term in 1869, Huxley elaborated on agnosticism in 1889 to frame the nature of claims in terms of what is knowable and what is not. Huxley states Agnosticism, in fact, is not a creed, but a method, the fundamental axiom of modern science. In matters of the intellect, follow your reason as far as it will take you, in matters of the intellect, do not pretend that conclusions are certain which are not demonstrated or demonstrable. Use of that term has continued to the present day, Huxley had little formal schooling and was virtually self-taught. He became perhaps the finest comparative anatomist of the latter 19th century and he worked on invertebrates, clarifying relationships between groups previously little understood. Later, he worked on vertebrates, especially on the relationship between apes and humans, after comparing Archaeopteryx with Compsognathus, he concluded that birds evolved from small carnivorous dinosaurs, a theory widely accepted today. Thomas Henry Huxley was born in Ealing, which was then a village in Middlesex and he was the second youngest of eight children of George Huxley and Rachel Withers. Like some other British scientists of the century such as Alfred Russel Wallace. His father was a teacher at Ealing School until it closed. As a result, Thomas left school at age 10, after two years of formal schooling. Despite this unenviable start, Huxley was determined to educate himself and he became one of the great autodidacts of the nineteenth century. At first he read Thomas Carlyle, James Huttons Geology, in his teens he taught himself German, eventually becoming fluent and used by Charles Darwin as a translator of scientific material in German. He learned Latin, and enough Greek to read Aristotle in the original, later on, as a young adult, he made himself an expert, first on invertebrates, and later on vertebrates, all self-taught
10.
Archaeopteryx
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Archaeopteryx, sometimes referred to by its German name Urvogel, is a genus of bird-like dinosaurs that is transitional between non-avian feathered dinosaurs and modern birds. The name derives from the ancient Greek ἀρχαῖος meaning ancient, and πτέρυξ, between the late nineteenth century and the early twenty-first century, Archaeopteryx had been generally accepted by palaeontologists and popular reference books as the oldest known bird. Older potential avialans have since been identified, including Anchiornis, Xiaotingia, similar in size to a Eurasian magpie, with the largest individuals possibly attaining the size of a raven, the largest species of Archaeopteryx could grow to about 0.5 m in length. Despite their small size, broad wings, and inferred ability to fly or glide and these features make Archaeopteryx a clear candidate for a transitional fossil between non-avian dinosaurs and birds. Thus, Archaeopteryx plays an important role, not only in the study of the origin of birds and it was named from a single feather in 1861. That same year, the first complete specimen of Archaeopteryx was announced, over the years, ten more fossils of Archaeopteryx have surfaced. Despite variation among these fossils, most experts regard all the remains that have been discovered as belonging to a single species, most of these eleven fossils include impressions of feathers. Because these feathers are of a form, these fossils are evidence that the evolution of feathers began before the Late Jurassic. The type specimen of Archaeopteryx was discovered just two years after Charles Darwin published On the Origin of Species, Archaeopteryx was roughly the size of a raven, with broad wings that were rounded at the ends and a long tail compared to its body length. It could reach up to 500 millimetres in length, with an estimated mass of 0.8 to 1 kilogram. Archaeopteryx feathers, although less documented than its other features, were similar in structure to modern-day bird feathers. Despite the presence of numerous features, Archaeopteryx had many non-avian theropod dinosaur characteristics. Unlike modern birds, Archaeopteryx had small teeth, as well as a bony tail. Because it displays features common to both birds and non-avian dinosaurs, Archaeopteryx has often considered a link between them. For instance, it has an ascending process of the ankle bone, interdental plates, an obturator process of the ischium. In particular, Ostrom found that Archaeopteryx was remarkably similar to the theropod family Dromaeosauridae, specimens of Archaeopteryx were most notable for their well-developed flight feathers. They were markedly asymmetrical and showed the structure of feathers in modern birds. The tail feathers were asymmetrical, again in line with the situation in modern birds
11.
Hesperornis
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Hesperornis is a genus of flightless aquatic birds that spanned the first half of the Campanian age of the Late Cretaceous period. One of the discoveries of the paleontologist O. C. Marsh in the late 19th century Bone Wars, it was a find in the history of avian paleontology. Locations for Hesperornis fossils include the Late Cretaceous marine limestones from Kansas, nine species are recognised, eight of which have been recovered from rocks in North America and one from Russia. Hesperornis was a bird, reaching up to 1.8 metres in length. It had virtually no wings, and swam with its hind legs. Fossil evidence shows that the toes were probably lobed, as in todays grebes, like many other Mesozoic birds such as Ichthyornis, Hesperornis had teeth as well as a beak, which were used to hold prey. The teeth of Hesperornis were present along nearly the entire lower jaw, the front portion of the upper jaw and tip of the lower jaw lacked teeth and were probably covered in a beak. Studies of the surface show that at least the tips of the jaws supported a hard. The palate contained small pits that allowed the teeth to lock into place when the jaws were closed. They also retained a dinosaur-like joint between the jaw bones. It is believed that this allowed them to rotate the back portion of the mandible independently of the front, the first Hesperornis specimen was discovered in 1871 by Othniel Charles Marsh. Marsh was undertaking his second expedition, accompanied by ten students. The team headed to Kansas where Marsh had dug before, aside from finding more bones belonging to the flying reptile Pteranodon, Marsh discovered the skeleton of a large fossil bird, at least five feet in height. The specimen was large, wingless, and had strong legs—Marsh considered it a diving species, unfortunately, the specimen lacked a head. Marsh named the find Hesperornis regalis, or regal western bird, Marsh headed back west with a smaller party the following year. In western Kansas, one of Marshs four students, Thomas H. Russell and this specimen had enough of its head intact that Marsh could see that the creatures jaws had been lined with teeth. Marsh saw important evolutionary implications of this find, along with Benjamin Mudges find of the toothed bird Ichthyornis, in an 1873 paper Marsh declared that the fortunate discovery of these interesting fossils does much to break down the old distinction between Birds and Reptiles
