In Xenopus laevis, five different types were identified which are present in different expression patterns during the different stages of the embryonic development.

Developmental biologists inject Morpholino oligos into eggs or embryos of zebrafish, African clawed frog ( Xenopus ), sea urchin, and killifish ( F. heteroclitus ) producing morphant embryos, or electroporate Morpholinos into chick embryos at later stages of development.

Useful models of dendritic arbor formation are the Xenopus tadpoles, which are transparent in early stages of larval development and allow for dye-labeled neurons to be repeatedly imaged in the intact animal over several weeks.

All vertebrate brains share a common underlying form, which appears most clearly during early stages of embryonic development.

Comparing different embryonic stages of different animals is a tool that can be used to infer relationships between species, and thus biological evolution.

By comparing different embryonic stages of different vertebrate species, he formulated the Recapitulation theory.

Haeckel ’ s 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 addition of terminal adult stages and the telescoping, or driving back, of such stages to descendant ’ s embryonic stages are likewise representative of Haeckelian embryonic development.

Haeckel ’ s opponents believe that he de-emphasizes the differences between early embryonic stages in order to make the similarities between embryos of different species more pronounced.

R. Bender ultimately goes so far as to reject His's claims regarding the fabrication of certain stages of development in Haeckel's drawings, arguing that Haeckel's embryo drawings are faithful representations of real stages of embryonic development in comparison to published embryos.

An example of modern paleontological progress is the application of synchrotron X-ray tomographic techniques to early Cambrian bilaterian embryonic microfossils that has recently yielded new insights of metazoan evolution at its earliest stages.

In the rare instances that they develop to postimplantation stages, gynogenetic embryos show better embryonic development relative to placental development, while for androgenones, the reverse is true.

Even in animals, cytokinesis and mitosis may occur independently, for instance during certain stages of fruit fly embryonic development.

While examples of embryonic stages show that molecular features of ancestral organisms exist, the theory of recapitulation itself has been viewed within the field of developmental biology as a historical side-note rather than as dogma.

Darwin's view, that early embryonic stages are similar to the same embryonic stage of related species but not to the adult stages of these species, has been confirmed by modern evolutionary developmental biology.

He remarks that some rudimentary organs, such as teeth in baleen whales, are found only in embryonic stages.

Studies done on the potential of the embryo at different stages have shown that at both the two and four cell stage of development P. flava blastomeres can go on to give rise to a tornaria larvae, so fates of these embryonic cells don ’ t seem to be established till after this stage.

It was widely supported in the Edinburgh and London schools of higher anatomy around 1830, notably by Robert Edmond Grant, but was opposed by Karl Ernst von Baer's embryology of divergence in which embryonic parallels only applied to early stages where the embryo took a general form, after which more specialised forms diverged from this shared unity in a branching pattern.

This land is in various stages of development in several locations throughout the town.

It must be recognized that countries at different stages of development have very different capabilities of meeting such conditions.

Thus, although the agenda of external assistance in the economic sphere are cumulative, and many of the policies suggested for nations in the earlier stages remain relevant, the basic purpose of American economic policy during the later stages of development should be to assure that movement into a stage of self-sustaining growth is not prevented by lack of foreign exchange.

In effect, rather than making plate armour obsolete, the use of firearms stimulated the development of plate armour into its later stages.

In software development, UAT is one of the final stages of a project and often occurs before a client or customer accepts the new system.

At the earliest stages of brain development, the three areas are roughly equal in size.

Some breasts are mounted high upon the chest wall, are of rounded shape, and project almost horizontally from the chest, which features are common to girls and women in the early stages of thelarchic development, the sprouting of the breasts.

The Tanner Scale indicates the five development stages of the secondary sex characteristics ( breasts and pubic hair ) of girls and women.

For a girl in puberty, during thelarche ( the breast-development stage ), the female sex hormones ( principally estrogens ) promote the sprouting, growth, and development of the breasts, in the course of which, as mammary glands, they grow in size and volume, and usually rest on her chest ; these development stages of secondary sex characteristics ( breasts, pubic hair, etc.

While there are self-contained departments for the creation of arcade, pachinko and pachislo, online, and mobile games, the Consumer Games R & D Division instead is an amalgamation of subsections in charge of various game development stages.

The other motorways are in various early stages of development, coming up to a total of 13 motorway routes.

Robert M. Price described in his essay " H. P. Lovecraft and the Cthulhu Mythos " two stages in the development of the Cthulhu Mythos.

Furthermore, the composition and properties of chromatin vary from one cell type to the another, during development of a specific cell type, and at different stages in the cell cycle.

As a result, his art was sometimes criticized as being “ vulgar ,” because he painted what he saw: “ rutted and edged hodgepodge of bushes, mounds of earth, and trees in various stages of development .” According to one source, details such as those were equivalent to today ’ s art showing garbage cans or beer bottles on the side of a street scene.

With regard to development, he described principles rather than stages.

The forest area change may follow a pattern suggested by the forest transition ( FT ) theory, whereby at early stages in its development a country is characterized by high forest cover and low deforestation rates ( HFLD countries ).

Countries with high forest cover can be expected to be at early stages of the FT. GDP per capita captures the stage in a country ’ s economic development, which is linked to the pattern of natural resource use, including forests.

Among them are Erik Erikson's eight stages of psychosocial development and John B. Watson's and B. F. Skinner's behaviorism.

* Erik Erikson: Erikson's stages of psychosocial development

* Lawrence Kohlberg: Kohlberg's stages of moral development

The economy embarked on various stages of development during which the public and private sectors played roles varying in relative importance as follows:

Clements ' superorganism concept proposed that ecosystems progress through regular and determined stages of seral development that are analogous to the developmental stages of an organism.

It ranged from a freshman woman, just married, through the various academic growth stages, including one senior-graduate student, to a young faculty member recently married to a senior man who also attended.

It ranged from those with no children, through students in various stages of pregnancy, to one 44-year-old male with four children, three of whom were teenagers.

Finally, information is retrieved from the dictionary as required by stages of the translation process -- the grammatical description for sentence-structure determination, equivalent-choice information for semantic analysis, and target-language equivalents for output construction.

By this procedure rinsing progresses in two stages, first by dilution until the time when the drains are separated and thereafter by displacement of the soil-bearing liquor by clean rinse water, since soiled liquor squeezed from the specimens at the nip passes directly to waste from the suds box drains.

He recognized that whatever transformation may be effected in the first stage of an R-stage process, the remaining stages must use an optimal Af-stage policy with respect to the state resulting from the first stage, if there is to be any chance of optimizing the complete process.

Proceeding in this way, from one to two and from two to three stages, we may gradually build up the policy for any number.

In finding the optimal R-stage policy from that of Af stages, only the function Af is needed.

Still others sprang up late in the century to meet conditions which arose from fresh stages of the revolutionary age.

Anaxagoras proceeded to give some account of the stages in the process from original chaos to present arrangements.

The signal amplifier ( from the microvolt range to fractions of a volt ) performs amplification to the IF stages.

Interestingly, viruses can remain intact from apoptosis particularly in the latter stages of infection.

Pseudolus, an excellent liar, uses Philia's cheery disposition to convince Lycus that she has picked up a plague from Crete, which causes its victims to smile endlessly in its terminal stages.

It was formed from the nationalisation of the " Big Four " British railway companies and lasted until the gradual privatisation of British Rail, in stages between 1994 and 1997.

To anonymous laborers fell the less skilled stages of brick production: mixing clay and water, driving oxen over the mixture to trample it into a thick paste, scooping the paste into standardized wooden frames ( to produce a brick roughly 42 cm long, 20 cm wide, and 10 cm thick ), smoothing the surfaces with a wire-strung bow, removing them from the frames, printing the fronts and backs with stamps that indicated where the bricks came from and who made them, loading the kilns with fuel ( likelier wood than coal ), stacking the bricks in the kiln, removing them to cool while the kilns were still hot, and bundling them into pallets for transportation.

The term " Bronze Age " ultimately derives from the Ages of Man, the stages of human existence on the Earth according to Greek mythology.

By the mid-20th century, the number of examples of people skipping stages, such as going from hunter-gatherers to post-industrial service occupations in one generation, were so numerous that 19th-century evolutionism was effectively disproved.

The faunal stages from youngest to oldest, together with some of their subdivisions, are:

A subdivision in eleven stages, all originating from European stratigraphy, is now used worldwide.

Signals arising from sensory organs are transmitted to the brain and then processed in a series of stages, which extract multiple types of information from the raw input.

Castration before puberty ( or in its early stages ) prevents a boy's larynx from being transformed by the normal physiological events of puberty.