In biology, the theory that states that an animal's development from embryo to adult resembles the stages in the evolution of its ancestors is commonly expressed as what three word phrase?
"tool that can be used to infer relationships between species, and thus biological evolution. This has been a source of quite some controversy, both now and in the past. Ernst Haeckel pioneered in this field. By comparing different embryonic stages of different vertebrate species, he formulated the recapitulation theory. This theory states that an animal's embryonic development follows exactly the same sequence as the sequence of its evolutionary ancestors. Haeckel's work and the ensuing controversy linked the fields of developmental biology and comparative anatomy into comparative embryology. From a more modern perspective, Haeckel's drawings were the beginnings of the field"
"stages made it even more difficult to compare different species. It was agreed by all European evolutionists that all vertebrates looked very similar at an early stage, in what was thought of as a common ideal type, but there was a continuing debate from the 1820s between the Romantic recapitulation theory that human embryos developed through stages of the forms of all the major groups of adult animals, literally manifesting a sequence of organisms on a linear chain of being, and Karl Ernst von Baer's opposing view, stated in von Baer's laws of embryology, that the early general forms diverged"
"of adulthood) and consideration of proximate ontogenetic and environmental factors (i.e., how development happens) in addition to more ultimate factors (i.e., why development happens), which are the focus of mainstream evolutionary psychology. <section end=Lead /> Like mainstream evolutionary psychology, EDP is rooted in Charles Darwin's theory of natural selection. Darwin himself emphasized development, using the process of embryology as evidence to support his theory. From ""The Descent of Man"":""Man is developed from an ovule...which differs in no respect from the ovules of other animals. The embryo itself at a very early period can hardly be distinguished from that of other"
"The Generation of Animals that the morphological differences among the different embryos arose late in development. In 1828, Karl Ernst von Baer created his laws of embryology, which summarized the results of his comparative embryogenesis studies. In his first law, he proposed that the more general characters of a group appear earlier in their embryos than the more special characters. In 1866, Ernst Haeckel proposed that each developing organism passes through the evolutionary stages of its ancestors, i.e., ontogeny recapitulates phylogeny. The hypothesis that different organisms pass through the developmental stages of closely related organisms is outdated. However, the idea"
"has come to embody Haeckel's Biogenetic Law, for embryonic development is a recapitulation of evolution. Haeckel proposes that all classes of vertebrates pass through an evolutionarily conserved “phylotypic” stage of development, a period of reduced phenotypic diversity among higher embryos. Only in later development do particular differences appear. Haeckel portrays a concrete demonstration of his Biogenetic Law through his ""Gastrea"" theory, in which he argues that the early cup-shaped gastrula stage of development is a universal feature of multi-celled animals. An ancestral form existed, known as the gastrea, which was a common ancestor to the corresponding gastrula. Haeckel argues that"
"as well. For example, numerous invertebrate species release a larva before development is complete; at the end of the larval period, an animal for the first time comes to resemble an adult similar to its parent or parents. Although invertebrate embryology is similar in some ways for different invertebrate animals, there are also countless variations. For instance, while spiders proceed directly from egg to adult form, many insects develop through at least one larval stage. Embryology is central to evolutionary developmental biology (""evo-devo""), which studies the genetic control of the development process (e.g. morphogens), its link to cell signalling, its"
"Epigenesis (biology) In biology, epigenesis (or, in contrast to preformationism, neoformationism) is the process by which plants, animals and fungi develop from a seed, spore or egg through a sequence of steps in which cells differentiate and organs form. Aristotle first published the theory of epigenesis in his book ""On the Generation of Animals."" Although epigenesis appears to be an obvious fact in today's genetic age, historically creationist theories of life's origins hindered its acceptance. However, during the late 18th century an extended and controversial debate among biologists finally led epigenesis to eclipse the long-established preformationist view. The embryologist Caspar"
"when genes are expressed in a new pattern, or when toolkit genes acquire additional functions. Another possibility is the Neo-Lamarckian theory that epigenetic changes are later consolidated at gene level, something that may have been important early in the history of multicellular life. A recapitulation theory of evolutionary development was proposed by Étienne Serres in 1824–26, echoing the 1808 ideas of Johann Friedrich Meckel. They argued that the embryos of 'higher' animals went through or recapitulated a series of stages, each of which resembled an animal lower down the great chain of being. For example, the brain of a human"
"mean a change with respect to the development of the same organ in the animal's ancestors. In 1928, the English embryologist Walter Garstang showed that tunicate larvae shared structures such as the notochord with adult vertebrates, and suggested that the vertebrates arose by paedomorphosis (neoteny) from such a larva. De Beer anticipated evolutionary developmental biology in his 1930 book ""Embryos and Ancestors"", showing that evolution could occur by heterochrony, such as in paedomorphosis, the retention of juvenile features in the adult. De Beer argued that this enabled rapid evolutionary change, too brief to be recorded in the fossil record, and"
"notational systems that reify different kinds of abstract entity. Popper is considered by many to have given evolutionary epistemology its first comprehensive treatment, though Donald T. Campbell coined the phrase in 1974 and Piaget alluded to it in 1974 and described the concept as one of five possible theories in ""The Origins of Intelligence in Children"" (1936). Evolutionary epistemology Evolutionary epistemology refers to three distinct topics: (1) the biological evolution of cognitive mechanisms in animals and humans, (2) a theory that knowledge itself evolves by natural selection, and (3) the study of the historical discovery of new abstract entities such"
"a reptilian stage before completing their development as mammals. Such a reenactment, often called ""recapitulation theory"", is not supported by scientific evidence. What does occur, however, is that the first stages of development are similar in broad groups of organisms. At very early stages, for instance, all vertebrates appear extremely similar, but do not exactly resemble any ancestral species. As development continues, specific features emerge from this basic pattern. Homology includes a unique group of shared structures referred to as ""vestigial structures"". ""Vestigial"" refers to anatomical parts that are of minimal, if any, value to the organism that possesses them."
"""Zoönomia"" mainly when writing about the ""three great objects of desire"" for every organism: ""lust, hunger, and security."" A similar ""survival of the fittest"" view in ""Zoönomia"" is Erasmus' view on how a species ""should"" propagate itself. Erasmus' idea that ""the strongest and most active animal should propagate the species, which should thence become improved"". Today, this is called the theory of survival of the fittest. His grandson Charles Darwin, much less libidinous and who led more of an invalid life, and who is not known to have illegitimately fathered children, or fathered children he did not plan, acknowledge and"
"Evolutionary epistemology Evolutionary epistemology refers to three distinct topics: (1) the biological evolution of cognitive mechanisms in animals and humans, (2) a theory that knowledge itself evolves by natural selection, and (3) the study of the historical discovery of new abstract entities such as abstract number or abstract value that necessarily precede the individual acquisition and usage of such abstractions. ""Evolutionary epistemology"" can refer to a branch of epistemology that applies the concepts of biological evolution to the growth of animal and human cognition. It argues that the mind is in part genetically determined and that its structure and function"
"described both topically (by organ) and chronologically (by time) with major occurrences being listed by gestational age. In other animals the very early stages of embryogenesis are the same as those in humans. In later stages, development across all taxa of animals and the length of gestation vary. Different terms are used to describe prenatal development, meaning development before birth. A term with the same meaning is the ""antepartum"" (from Latin ""ante"" ""before"" and ""parere"" ""to give birth"") Sometimes ""antepartum"" is however used to denote the period between the 24th/26th week of gestational age until birth, for example in antepartum"
"century through most of the 20th century, embryology faced a mystery. Animals were seen to develop into adults of widely differing body plan, often through similar stages, from the egg, but zoologists knew almost nothing about how embryonic development was controlled at the molecular level, and therefore equally little about how developmental processes had evolved. Charles Darwin argued that a shared embryonic structure implied a common ancestor. As an example of this, Darwin cited in his 1859 book ""On the Origin of Species"" the shrimp-like larva of the barnacle, whose sessile adults looked nothing like other arthropods; Linnaeus and Cuvier"
"Lehre"" (""""On Darwin's Doctrine""""), published in the year of his death in 1876. Von Baer's laws (embryology) Von Baer's laws of embryology (or laws of development) are four rules discovered by Karl Ernst von Baer to explain the observed pattern of embryonic development in different species. Von Baer formulated the laws in the book ""Über Entwickelungsgeschichte der Thiere"" (""""On the Developmental History of Animals""""), published in 1828, while working at the University of Königsberg. He specifically intended to rebut Johann Friedrich Meckel's 1808 recapitulation theory. According to that theory, embryos pass through successive stages that represent the adult forms of"
"Developmental biology Developmental biology is the study of the process by which animals and plants grow and develop. Developmental biology also encompasses the biology of regeneration, asexual reproduction, metamorphosis, and the growth and differentiation of stem cells in the adult organism. In the late 20th century, the discipline largely transformed into evolutionary developmental biology. The main processes involved in the embryonic development of animals are: regional specification, morphogenesis, cell differentiation, growth, and the overall control of timing explored in evolutionary developmental biology: The development of plants involves similar processes to that of animals. However plant cells are mostly immotile so"
"Adult development Adult development encompasses the changes that occur in biological and psychological domains of human life from the end of adolescence until the end of one's life. These changes may be gradual or rapid, and can reflect positive, negative, or no change from previous levels of functioning. Changes occur at the cellular level and are partially explained by biological theories of adult development and aging. Biological changes influence psychological and interpersonal/social developmental changes, which are often described by stage theories of human development. Stage theories typically focus on “age-appropriate” developmental tasks to be achieved at each stage. Erik Erikson"
"Homology was later explained by Charles Darwin's theory of evolution in 1859, but had been observed before this, from Aristotle onwards, and it was explicitly analysed by Pierre Belon in 1555. In developmental biology, organs that developed in the embryo in the same manner and from similar origins, such as from matching primordia in successive segments of the same animal, are serially homologous. Examples include the legs of a centipede, the maxillary palp and labial palp of an insect, and the spinous processes of successive vertebrae in a vertebral column. Male and female reproductive organs are homologous if they develop"
"age, or eleventh-week gestational age. After this time the embryo is referred to as a fetus. First attested in English in the mid-14c., the word ""embryon"" derives from Medieval Latin ""embryo"", itself from Greek (""embruon""), lit. ""young one"", which is the neuter of (""embruos""), lit. ""growing in"", from ἐν (""en""), ""in"" and βρύω (""bruō""), ""swell, be full""; the proper Latinized form of the Greek term would be ""embryum"". In animals, the development of the zygote into an embryo proceeds through specific recognizable stages of blastula, gastrula, and organogenesis. The blastula stage typically features a fluid-filled cavity, the blastocoel, surrounded by"
"stage between larvae and adult. In 1883, John Lubbock revitalized Harvey's hypothesis and argued that the origin and evolution of holometabolan development can be explained by the precocious eclosion of the embryo. Hemimetabolan species, whose larvae look like the adult, have an embryo that completes all developmental stages (namely: ""protopod"", ""polipod"", and ""oligopod"" stages) inside the eggshell. Holometabolan species instead have vermiform larvae and a pupal stage after incomplete development and hatching. The debate continued through the twentieth century, with some authors (like Charles Pérez in 1902) claiming the precocious eclosion theory outlandish, Antonio Berlese reestablishing it as the leading"
"of reason”, in which “one organic being [is] derived from another organic being, although from one which is specifically different; e.g., certain water-animals transform themselves gradually into marsh-animals and from these, after some generations, into land-animals.” Some 20th-century philosophers, such as Eric Voegelin, credit Kant with foreshadowing modern evolutionary theory. In 1796, Erasmus Darwin published his ""Zoönomia"", which suggested ""that all warm-blooded animals have arisen from one living filament ... with the power of acquiring new parts"" in response to stimuli, with each round of improvements being inherited by successive generations. In his 1802 poem ""Temple of Nature"", he described"
"embryogenesis and have, at least at this developmental stage, the three germ layers and undergo gastrulation. While embryogenesis has been studied for more than a century, it was only recently (the past 15 years or so) that scientists discovered that a basic set of the same proteins and mRNAs are involved in all of embryogenesis. This is one of the reasons that model systems such as the fly (""Drosophila melanogaster""), the mouse (Muridae), and the leech (""Helobdella""), can all be used to study embryogenesis and developmental biology relevant to other animals, including humans. The fate map of the nematode (""Caenorhabditis)"""
"Evolution of mammals The evolution of mammals has passed through many stages since the first appearance of their synapsid ancestors in the late Carboniferous period. The most ancestral forms in the class Mammalia are the egg-laying mammals in the subclass Prototheria. This class first started out as something close to the platypus and evolved to modern day mammals. By the mid-Triassic, there were many synapsid species that looked like mammals. The lineage leading to today's mammals split up in the Jurassic; synapsids from this period include ""Dryolestes"", more closely related to extant placentals and marsupials than to monotremes, as well"
"but this characterization is no longer commonly agreed. Anaximander's hypothesis could be considered ""evolution"" in a sense, although not a Darwinian one. Empedocles (c. 490 – 430 BC), argued that what we call birth and death in animals are just the mingling and separations of elements which cause the countless ""tribes of mortal things."" Specifically, the first animals and plants were like disjointed parts of the ones we see today, some of which survived by joining in different combinations, and then intermixing during the development of the embryo, and where ""everything turned out as it would have if it were"
"same geological strata as trilobites, it would be evidence against natural selection. Survival of the fittest ""Survival of the fittest"" is a phrase that originated from Darwinian evolutionary theory as a way of describing the mechanism of natural selection. The biological concept of fitness is defined as reproductive success. In Darwinian terms the phrase is best understood as ""Survival of the form that will leave the most copies of itself in successive generations."" Herbert Spencer first used the phrase, after reading Charles Darwin's ""On the Origin of Species"", in his ""Principles of Biology"" (1864), in which he drew parallels between"
"on evolution as fact and theory. Evolution has been described as ""fact and theory""; ""fact, not theory""; ""only a theory, not a fact""; ""multiple theories, not fact""; and ""neither fact, nor theory."" The disagreements among these statements, however, have more to do with the meaning of words than the substantial issues and this controversy is discussed below. Professor of biology Jerry Coyne sums up biological evolution succinctly: This shows the breadth and scope of the issue, incorporating the scientific fields of zoology, botany, genetics, geology, and paleontology, among many others. But the central core of evolution is generally defined as"
"active. Evolution of mammals The evolution of mammals has passed through many stages since the first appearance of their synapsid ancestors in the late Carboniferous period. The most ancestral forms in the class Mammalia are the egg-laying mammals in the subclass Prototheria. This class first started out as something close to the platypus and evolved to modern day mammals. By the mid-Triassic, there were many synapsid species that looked like mammals. The lineage leading to today's mammals split up in the Jurassic; synapsids from this period include ""Dryolestes"", more closely related to extant placentals and marsupials than to monotremes, as"
"develop, and how all animals are related. It also supports evolutionary theory, in the sense that all vertebrates develop similarly and have a common ancestor. Comparative embryology Comparative embryology is the branch of embryology that compares and contrasts embryos of different species, showing how all animals are related. Aristotle was the earliest person in recorded history to study embryos. Observing embryos of different species, he described how animals born in eggs (oviparously) and by live birth (viviparously) developed differently. He discovered there were two main ways the egg cell divided: holoblasticly, where the whole egg divided and became the creature;"
"evolutionary principle of neoteny (a phenomenon of adult retention of juvenile-like morphology or behaviour) has been invoked to explain the origin of human characteristics from ape ancestors. The storyline suggests that if we lived longer, we would continue to develop along the path of an ape and eventually become ape-like. Huxley came from a well-known family of biologists, and his grasp of the principle of neoteny seems to reflect this influence. The story has been interpreted as the British Huxley's contemptuous nod to the Hearstian reality of the United States in the early part of the 20th century: Jo Stoyte"
"through a series of lower forms. In his view, lower animals were simply newcomers on the evolutionary scene. After Darwin's ""On the Origin of Species"", the idea of ""lower animals"" representing earlier stages in evolution lingered, as demonstrated in Ernst Haeckel's figure of the human pedigree. While the vertebrates were then seen as forming a sort of evolutionary sequence, the various classes were distinct, the undiscovered intermediate forms being called ""missing links."" Haeckel claimed that human evolution occurred in 24 stages and that the 23rd stage was a theoretical missing link he named ""Pithecanthropus alalus"" (""ape-man lacking speech""). Haeckel claimed"
"illustrations show vertebrate embryos at different stages of development, which exhibit embryonic resemblance as support for evolution, recapitulation as evidence of the Biogenetic Law, and phenotypic divergence as evidence of von Baer's laws. The series of twenty-four embryos from the early editions of Haeckel's ""Anthropogenie"" remain the most famous. The different species are arranged in columns, and the different stages in rows. Similarities can be seen along the first two rows; the appearance of specialized characters in each species can be seen in the columns and a diagonal interpretation leads one to Haeckel's idea of recapitulation. Haeckel's embryo drawings are"
"mother and the fetus. Placentas are a defining characteristic of placental mammals, but are also found in marsupials and some non-mammals with varying levels of development. The homology of such structures in various viviparous organisms is debatable, and in invertebrates such as Arthropoda, is analogous at best. Childhood is the age span ranging from birth to adolescence. In developmental psychology, childhood is divided up into the developmental stages of toddlerhood (learning to walk), early childhood (play age), middle childhood (school age), and adolescence (puberty through post-puberty). Various childhood factors could affect a person's attitude formation. The Tanner stages can be"