"It is to be remembered that at all stages the embryo is a living organism, that is, it is a going concern with adequate mechanisms for its maintenance as of that time." [Carnegie Stages of Early Human Embryonic Development: http://nmhm.washingtondc.museum/collections/hdac/stage3.pdf]
What a great idea! Now anyone interested in the long-known and long-documented accurate scientific facts of human embryology can simply download an iPhone app into their iPhones, or onto any computer, that takes them immediately to the Carnegie Stages of Early Human Embryonic Development!
Below are included instructions of how to download the iPhone app, as well as how to maneuver the "Virtual Embryo" website that the app takes you to. It's easy, and fun!
Since the Carnegie Stages appear to address only human sexual reproduction, also included below is a section on human "a-sexual" reproduction by means of "twinning", with direct quotes from Carnegie Stages 2, 3, 4 and 5, as well as quotes from human molecular genetics texts. If one is truly concerned with protecting the inherent life and dignity of all human beings, then that must include human beings both sexually and asexually reproduced.
Also included below are brief lists of important scientific terms accurately defined which should help to dispel at least some of the myriad of scientific "myths" that seem to have taken over much of the discussion and debates on current issues involving the human embryo. This would include discussions, debates, articles and books on abortion, the use of abortifacients, human embryo research, human embryonic stem cell research, human cloning and other genetic engineering research, regenerative medicine, "personhood" initiatives, etc. Normally these would follow the documented scientific passages included below. However, since most readers might not be familiar with the significance of some of the scientific terms used in those passages, I have put this short section on scientific "myths" first for their consideration.
One of the common concerns in these various articles and debates is that each term used to describe the human embryo at various stages of development can be used in national and international legal documents (bills, laws, amendments, regulations, etc.). The mis-use or falsification of such terms in legal documents is often purposefully used as a means of inserting legal "loopholes" for political or other agendas. This often happens because lawyers at least understand that the courts are usually legally required to interpret such terms as "exclusionary", i.e., the law would only apply to precisely those entities as are formally defined in that law. (So if a law defines all bears as "brown", then it would not cover any bears that are "black" or "white"; or, if the definition in a law is scientifically erroneous, the law would only apply to whatever that false scientific definition refers to).
Finally, bioethics lawyers have succeeded for decades in transferring the legal definitions they obtain for issues involving the beginning of life issues to legal definitions involving the end of life (and vice versa). For example, the term "right to privacy" was transferred from the abortion issue to euthanasia and physician assisted suicide issues at the end of life. Recently, the erroneous definition of "brain death" used at the end of life was applied to determining when a new human being begins to exist - after the formation of the brain! Thus any erroneous scientific "myths" that permeate these beginning of life issues will have a direct impact and influence on many end of life issues as well. This applies especially now to the various "personhood" initiatives roaming around this country and the world. If you're not legally a "person" at the beginning of life, then you are probably not going to legally considered a "person" at the end of life.
Thanks to USA.gov, their new iPhone app entitled, "Embryo", from the National Library of Medicine, is now available at: http://apps.usa.gov/embryo/. It is necessary to have iTunes for this application, but you can download it free from this same site (also downloads onto all computers).
As noted on this government website:
Scientists and educators have used the Carnegie Embryo Collection, housed at the National Museum of Health and Medicine, to define normal human embryo development for decades. A database, called the Virtual Human Embryo, has been created to provide digital serial sections of human embryos from the collection. ... This project is a collaboration between:
• National Library of Medicine
• Eunice Kennedy Shriver National Institute of Child Health and Human Development
• Louisiana State University Health Sciences Center
• National Museum of Health & Medicine, Human Developmental Anatomy Center [The Carnegie Stages of Early Human Embryonic Development]
In order to use the iPhone app for "Embryo", I have included step-by-step directions below. The app actually takes the reader to the main website of "The Virtual Embryo", at Louisiana State University Health Sciences Center:
1. Click into the home page of The Virtual Human Embryo, at the Louisiana State University Health Sciences Center, New Orleans: http://virtualhumanembryo.lsuhsc.edu/
"The Virtual Human Embryo Project was originally developed as a collaboration between embryologist Dr. Raymond Gasser at LSUHSC and the HDAC in Washington DC. The overall aim of the project is to make the Carnegie collection, which is housed at the HDAC, accessible for research and teaching of human embryology. Dr. John Cork at LSUHSC joined the project at its inception as the software developer with a special interest in 3D-reconstruction. The project has two components, both of which are supported by grants from the National Institutes of Health."
2. To the left of the main page, click into "DREM Project" that will take you to: http://virtualhumanembryo.lsuhsc.edu/DREM/DREM_home.htm.
3. This is the "entrance" page for Digitally Reproduced Embryonic Morphology (DREM). Click into "Enter", and that will take you to the DREM Project Home Page: http://virtualhumanembryo.lsuhsc.edu/DREM/DREM_home.htm
"The overall objective of the DREM project is to produce a series of image databases, one for each of the 23 stages of human embryonic development. Each database will include a complete serially sectioned embryo selected from the best examples in the Carnegie collection."
4. To the left of the DREM Project Home Page, click into "Demo" that will take you to a listing of all 23 Carnegie Stages of the Early Human Embryo (covers the first full 8 weeks post-fertilization). Each of those "Stages" is a hyperlink, and you can take a look at each of the Stages to find the most current up-to-date scientific information on the early human embryo as documented by FIPAT, the international nomenclature committee on human embryology. [See their own website, updated again this January 2011, at: http://www.unifr.ch/ifaa/. For step-by-step explanation of how to use the FIPAT website, see my article, "Reliable URLs for Human Embryology: The Carnegie Stages of Early Human Embryonic Development" (April 20, 2011), at: http://www.lifeissues.net/writers/irv/irv_186carnegiestages.html.]
For example, if you click into "Stage 1" on the DREM Demo page, it will take you to STAGE 1: http://virtualhumanembryo.lsuhsc.edu/demos/Stage1/Stage1.htm. To the left of the page click into "INTRODUCTION": http://virtualhumanembryo.lsuhsc.edu/demos/Stage1/Intro_pg/Intro.htm. The scientific descriptions given there are addressed in more detail below.
The "Introduction" page for Stage 1 provides the most accurate scientific facts about the earliest human embryo (as the Carnegie Stages have done since their institutionalization in 1942, and continuously updated since then). It also dispels several scientific "myths" so current today, especially in debates concerning abortion, the use of abortifacients, human embryo research, human embryonic stem cell research, human cloning and other genetic engineering research, regenerative medicine, "personhood" initiatives, etc. For example, it documents that:
"The term 'pre-embryo' is not used here for the following reasons: (1) it is ill-defined because it is said to end with the appearance of the primitive streak or to include neurulation; (2) it is inaccurate because purely embryonic cells can already be distinguished after a few days, as can also the embryonic (not pre-embryonic!) disc; (3) it is unjustified because the accepted meaning of the word embryo includes all of the first 8 weeks; (4) it is equivocal because it may convey the erroneous idea that a new human organism is formed at only some considerable time after fertilization; and (5) it was [used] in 1986 'largely for public policy reasons' (Biggers). ... Just as postnatal age begins at birth, prenatal age begins at fertilization." (O'Rahilly and Muller 2001, p. 88) ... The ill-defined and inaccurate term pre-embryo, which includes the embryonic disc, is said either to end with the appearance of the primitive streak or to include neurulation. The term is not used in this book.. (O'Rahilly and Muller 1994, p. 55) ...
The term conception, however, may refer either to fertilization or to implantation and hence (like gestation) is best avoided." (O'Rahilly and Muller 2001, p. 19). (emphases added)
The term "ovum", which has been used for such disparate structures as an oocyte and a 3-week embryo, has no scientific usefulness and is not used here. Indeed, strictly speaking, "the existence of the ovum ... is impossible" (Franchi, 1970). The term "egg" is best reserved for a nutritive object frequently seen on the breakfast table. [Carnegie Stages of Early Human Embryonic Development, Stage One, at: http://nmhm.washingtondc.museum/collections/hdac/stage1.pdf.]
Here are short excerpts of the accurate scientific facts about Stage 1 of the developing human embryo documented and quoted here verbatim from the Carnegie Stages on the "Virtual Embryo" website, accessible now through the iPhone app. Stage 1 (a), (b), (c) includes the new unicellular human organism, the new human embryo, the new human being, who is sexually reproduced, and who begins to exist from the beginning of the process of fertilization. After that critical event, the new sexually reproduced human embryo simply continues to grow bigger and more complex continuously through the later embryonic, fetal, infant, childhood through adult stages of human development (emphases added for those unfamiliar with the science):
Digitally Reproduced Embryonic Morphology
STAGE 1
Introduction
Stage 1 is the unicellular embryo that contains unique genetic material and is an individually specific cell that has the potential to develop into all of the subsequent stages of a human being. It is the beginning of embryonic life and ontogenetic development that starts when an oocyte, arrested in metaphase of meiosis II, is penetrated by a sperm. This is the first event of fertilization. The embryo has a postovulatory age of approximately one day, is between 0.1 to 0.15 mm in diameter and weighs approximately 0.004 mg .
Fertilization is a series of events that begins when a sperm makes contact with an oocyte and ends with the intermingling of paternal (male) and maternal (female) chromosomes on the spindle at metaphase of the first mitotic division of the single cell. The events of fertilization require just over 24 hrs. to complete and normally take place in the ampulla of the uterine tube.
Stage 1 is divided into three substages; a, b and c. Stage 1a is referred to as the primordial embryo since all the genetic material necessary for the new individual, plus some redundant chromosomes, is now within a single plasma lemma (cell membrane). [Note: all of the components define the "embryo", not just the genes; and these components must work in sync with each other, thus themselves pre-determining the final coding of the genome - which itself can change.] From the perspective of the female gamete it has also been named the penetrated oocyte. The fertilizing sperm has passed through the zona (capsula) pellucida and its plasmalemma has fused with that of the oocyte.
Penetration activates the embryo into resuming its arrested meiosis II and after anaphase it enters telophase with the expulsion of the redundant chromosomes as a second polar body. This marks the beginning of Stage 1b in which the single-cell is referred to as the pronuclear embryo. From the perspective of the female gamete it has also been named the ootid because its female component is haploid like a spermatid. However, in the pronuclear embryo there are two separate haploid components: one maternal, or female, pronucleus and one paternal, or male, pronucleus.
The pronuclei move toward each other and eventually compress their envelops where they lie adjacent near the center of the cell. Stage 1c is the last phase of fertilization and exists for a relatively short period. The pronuclear envelopes disappear and the parental chromosomes that were contained in separate pronuclei come together in a process called syngamy thereby establishing the genome of the embryo. The one-cell Stage 1c embryo is named the syngamic embryo or zygote. The chromosomes assume positions on the rapidly formed first mitotic spindle in preparation for cleavage.
"A-sexual" human reproduction refers to various methods of reproducing new human embryos without the immediate use of sperm and oocyte fusion (fertilization). Such methods include "twinning" (blastomere separation, blastocyst splitting, embryo multiplication, etc.) which can take place both naturally in the woman's body in vivo, and artificially in IVF/ART laboratories and clinics in vitro; pronuclei transfer; mitochondrial transfer; parthenogenesis, and many other kinds of genetic engineering (all documented for decades on PubMed and other scientific search engines). These methods have been recently mischaracterized in debates by some developmental biologists (a field grounded in gnostic elements of Darwin's theory of evolution).
As noted, one well-known asexual method of human reproduction is monozygotic (identical) "twinning". Since the "Virtual Embryo" only refers briefly to monozygotic twinning, the following section uses their website to transfer by hyperlink to the official website of the full Carnegie Stages at the National Museum of Health and Medicine. [See all 23 Carnegie Stages at: http://nmhm.washingtondc.museum/collections/hdac/Select_Stage_and_Lab_Manual.htm]. As will become clear, the natural in vivo asexual human reproductive process of monozygotic (identical) "twinning" is addressed there in Carnegie Stages 2, 3, 4, and 5 (and has been since 1942).
"... a blastomere isolated from the mammalian 2-cell organism is capable of forming a complete embryo. Separation of the early blastomeres is believed to account for about one-third of all cases [of monozygotic twinning]"
"Recapitulation, the So-Called Biogenetic Law. The theory that successive stages of individual development (ontogeny) correspond with ('recapitulate') successive adult ancestors in the line of evolutionary descent (phylogeny) became popular in the nineteenth century as the so-called biogenetic law. This theory of recapitulation, however, has had a regrettable influence on the progress of embryology (G. de Beer). ... According to the 'laws' of von Baer, general characters (e.g., brain, notochord) appear in development earlier than special characters (e.g., limbs, hair). Furthermore, during its development an animal departs more and more from the form of other animals. Indeed, the early stages in the development of an animal are not like the adult stages of other forms but resemble only the early stages of those animals. The pharyngeal clefts of vertebrate embryos, for example, are neither gills nor slits. Although a fish elaborates this region into gill slits, in reptiles, birds, and mammals it is converted into such structures as the tonsils and the thymus." (O'Rahilly and Muller 2001, p. 16) (emphases added)
As noted below, in the discussion of the bastocyst, we find one of many rejections of the old erroneous "biogenetic law" that became popular with the Darwinians especially in the 1930's. Oddly, the "biogenetic law", along with the equally false and rejected term "pre-embryo", is still perpetrated even now in some national and international laws governing abortion, human embryo research, human cloning, human genetic engineering, etc. (e.g., in Canada and Great Britain).
To read these current facts about natural human asexual reproduction by monozygotic "twinning", please go to Stage 2 on the official Carnegie Stages website (emphases added): http://nmhm.washingtondc.museum/collections/hdac/stage2.pdf
STAGE 2 http://nmhm.washingtondc.museum/collections/hdac/stage2.pdf
Stage 2 comprises specimens from 2 cells up to the appearance of the blastocystic (or segmentation) cavity. ... a blastomere isolated from the mammalian 2-cell organism is capable of forming a complete embryo. Separation of the early blastomeres is believed to account for about one-third of all cases of monozygotic twinning in the human (Corner, 1955). ...
Such twins should be dichorial and diamniotic (fig. 5-2). The fact that nearly 60 percent of dichorial twins (whether monozygotic or dizygotic) have two unfused placentae "indicates that the zona pellucida must have disappeared sufficiently long before implantation to allow the twins to become implanted in independent positions in the uterus" (Bulmer, 1970). Dizygotic twins, in contrast, are believed to arise from two oocytes, from a binucleate oocyte, or from a second polar body (Gedda, 1961). The successive cleavage divisions do not occur synchronously, ...
STAGE 3 http://nmhm.washingtondc.museum/collections/hdac/stage3.pdf
Stage 3 consists of the free (that is, unattached) blastocyst, a term used as soon as a cavity (the blastocystic, or segmentation, cavity) can be recognized by light microscopy. ...
[An example of rejection of the "biogenetic law"] It is necessary to stress that the cavity of the mammalian blastocyst is not the counterpart of the amphibian or the avian blastocoel. In the bird, the blastocoel is the limited space between the epiblast and the primary endoderm. The cavity of the mammalian blastocyst, however, corresponds to the subgerminal space together with the area occupied by the yolk (Torrey, personal communication, 1972).
The mammalian blastocyst differs from a blastula in that its cells have already differentiated into at least two types: trophoblastic and embryonic cells proper. Heuser and Streeter (1941) emphasized an important point by using stage 3 as an example: The blastocyst form is not to be thought of solely in terms of the next succeeding stage in development. It is to be remembered that at all stages the embryo is a living organism, that is, it is a going concern with adequate mechanisms for its maintenance as of that time.
It is no less true, however, that changes occur "in the growing organism and its environment which provide critically for the future survival of the organism" (Reynolds, 1954). Indeed, such morphological and functional changes during development "critically anticipate future morphological and functional requirements for the survival and welfare of the organism" (ibid.).
STAGE 4 http://nmhm.washingtondc.museum/collections/hdac/stage_4.htm
Stage 4, the onset of implantation, is reserved for the attaching blastocyst, which is probably 5-6 days old. [See "twinning" noted for Stage 4 in description of the next stage, Stage 5.]
STAGE 5 http://nmhm.washingtondc.museum/collections/hdac/stage5.pdf
Stage 5 comprises embryos that are implanted to a varying degree but are previllous, i.e., that do not yet show definite chorionic villi. Such embryos are believed to be 7-12 days old.
An amniotic cavity is found by stage 5. If duplication of the embryo occurs after the differentiation of the amnion, the resulting monozygotic twins should be monochorial and monoamniotic (fig. 5-2). It has been estimated that the frequency of monoamniotic twins among monozygotic twins is about 4 percent (Bulmer, 1970). About once in every 400 monozygotic twin pregnancies, the duplication is incomplete and conjoined ("Siamese") twins (e.g., the second specimen of Shaw, 1932) result.
Fig. 5-2. Diagram to illustrate the presumed mode of development of monozygotic twins in the human. Based partly on Corner (1955). There exist "three critical stages at which the division of the embryo to form monozygotic twins may occur" (Bulmer, 1970). At stage 2, before the differentiation of the trophoblast, separation of the blastomeres would result in twins with separate choria and amnia. At stage 3 (and presumably at stage 4) before differentiation of the amnion, duplication of the inner cell mass would result in twins with a common chorion but separate amnia. At stage 5, duplication of the embryonic disc would result in twins with a common chorion and amnion. Deceptive fusion of the membranes may occur subsequently in certain instances but "the placenta and membranes, if subjected to skilled examination, including microscopic study of the chorionamniotic walls when necessary, will generally yield a correct impression of the type of twinning" (Corner, 1955; see also Allen and Turner, 1971). Partial instead of complete embryonic separation would result in conjoined twins of the various types classified by Wilder (1904).
Strachan and Reed perhaps explain this most succinctly in describing one kind of cloning:
The term 'clones' indicates genetic identity and so can describe genetically identical molecules (DNA clones), genetically identical cells or genetically identical organisms. Animal clones occur naturally as a result of sexual reproduction. For example, genetically identical twins [momozygotic twins] are clones ... A form of animal cloning can also occur as a result of artificial manipulation to bring about a type of asexual reproduction. The genetic manipulation in this case uses nuclear transfer technology: a nucleus is removed from a donor cell then transplanted into an oocyte whose own nucleus has previously been removed. ... The individual providing the donor nucleus and the individual that develops from the 'renucleated' oocyte are usually described as "clones", but it should be noted that they share only the same nuclear DNA; they do not share the same mitochondrial DNA, unlike genetically identical twins. ... Wilmut et al (1997) reported successful cloning of an adult sheep. For the first time, an adult nucleus had been reprogrammed to become totipotent once more, just like the genetic material in the fertilized oocyte from which the donor cell had ultimately developed. ... Successful cloning of adult animals has forced us to accept that genome modifications once considered irreversible can be reversed and that the genomes of adult cells can be reprogrammed by factors in the oocyte to make them totipotent once again. [Tom Strachan and Andrew P. Read, Human Molecular Genetics 2 (New York: John Wiley & Sons, Inc, 1999), pp. 508-509]. (emphases added)
For far too long now those interested in exploiting living human embryos, and their "bits and pieces", for political, economic, legal, and many other agendas, have succeeded in massively confusing people and in corrupting their consciences - not to mention corrupting the science of human embryology itself in spurious textbooks and "research studies". This corruption is now institutionalized and legalized, and spreading like a cancer. If it is not stopped now and exposed for the fraud that it is, it will slowly engulf and corrupt the "science" used in fields and issues now unrelated to the early human embryo and human fetus. If "scientists" will lie about this issue, they will gladly lie about any other issue. Enough is enough. Fortunately, with innovations such as the new iPhone app for the Carnegie Stages, the public will have the opportunity to identify for themselves what "facts" about human embryology are true and accurate, and which ones are not -- no longer relying entirely on fradulent scientific "experts" - none of whom have graduate degrees in human embryology.