Talk:2009 Group Project 5

From Embryology

Evaluation/ Alterations After Peer Review

--Joe Nassif 12:47, 14 October 2009 (EST)

• Edited structure of table of stages

• Corrected introduction " added a brief overview about frog and usage"

• In changed size of images to 200px and moved to the left to suit page

• Removed spaces and gaps between specific sections

• Formatted intro section to look neater and to flow more better

• Deleted the links and added proper reference

• Added to glossary of terms

• Added in text citations to the developments section

• Enhanced and added more definitions

• Changed reference list and changed the format it into APA format

• re-uploaded information and reference for images as stated by Mark Hill

• Added information below images for a description.

• Added links to source below images about the germa layer of frogs.

• Deleted image -unable to find copyright license in gastrualtion

• Changed to APA, had to look up dates and authors for incomplete references added by other students.

• Finished the glossary of terms

• Worked on current research about Frogs. Added relevant info about usage through history

• Proof read. Added in sentences to make the transition from history of use .

• Read through and edited spelling of development and stages

• Edit all information bout images. --Joe Nassif 12:47, 14 October 2009 (EST)

--Sando Rashed 09:51, 15 October 2009 (EST) edited all the image names to appropriate titles, added extra current research topic, fixed up some sentence structures, removed some signatures

--Sadaf Masood 11:45, 15 October 2009 (EST)

  • Added more information to the Current Embryology Research
  • More information on the Transgenesis techniques for functional genomics in Xenopus
  • Inserted diagram for Transgenesis
  • Inserted links for complete genome database of Xenopus Laevis and Xenopus Tropicalis
  • Link for Journal Article for Early Limb Development
  • Added more words for glossary

--Gang Liu 12:21, 15 October 2009 (EST)

  • Redid references of image of frog stage development;
  • Removed individual signatures;
  • Corrected typos;
  • Refomated stage of frog development

Group Project Updates

--Sando Rashed 00:08, 13 October 2009 (EST) i got rid of a few more individual signatures --Gang Liu 14:42, 8 October 2009 (EST)Hi group, one of the peer comments is to delete individual signature, so i got rid of all the signatures on the page.

--Mark Hill 10:08, 10 October 2009 (EST) The stage images you have begun to add to your project are from Xenbase - stages it is incorrect to give UNSW Embryology as the source as my page just provides links to this external site. "Digitized images and developmental data from Nieuwkoop and Faber (1994) Normal Table of Xenopus laevis (Daudin). Garland Publishing Inc, New York ISBN 0-8153-1896-0." you will need to get permission to use these images in your project.

--Gang Liu 22:22, 11 October 2009 (EST)Thank you Dr Hill. I've just realised. Yes, i will try to get permission from authors.

--Gang Liu 09:22, 14 October 2009 (EST)Hello, Dr Hill. I have tried to contact the publisher regarding permission to reproduce their images on my group project page. So far, i have not received any replies. Could i use your images on unsw embryology?

--Gang Liu 10:12, 14 October 2009 (EST) Hello, Dr Hill I just got the permission to reproduce those images on my page.

Project Updates

--Antonio Lee 10:57, 2 October 2009 (EST) Hi everyone, I will be working with you during the Lab10 Tutorial and here is the news link and PDF of the manuscript for your group exercise. I encourage you to read the paper before the tutorial. Also, please indicate next to the questions below (using either your initials or student number) which one of the four questions you wish to address.

Group 5 : Human Induced Pluripotent Stem Cells Retain Some Gene Expression Of Donor Cells in Science Daily Published online 19 September 2009 Manuscript (PDF): Transcriptional Signature and Memory Retention of Human-Induced Pluripotent Stem Cells

Question 1. What is the background to the existing problem / disease condition? (z3295026)- JOE NASSIF

The discovery of neural stem cells, has lead to the exposure that a single cellular factor can be carried out to re-program and stimulate a human cellular component into a pluripotent form, allow the cell to have the ability to distinguish any category of cellular material in the human body. The ability of this process will allow the identification of common cellular material and what is not common for instance abnormal tumour cell or cancer cells, this process of iPSCs is an advantage in recognising normal and abnormal cellular matter extrinistically as the stem cell will recognise what it going to develop into, through signalling and programming. These stem cells are extremely useful in therapeutic uses, muscular dystrophies and replacement of cell into the specific regions of the human body needed to be replaced or repaired.

An arrangement of four particular factors was experimented to generate iPSCs, using knowledge involving viral vectors including viruses with the possibility to influence the transcriptional configuration of the cellular material, at times inducing the cell death process and trying to destroy cancerous material in specific regions of the body.

The mouse and human genetics in relations to iPSCs have revealed to be comparable to embryonic stem cells in relation to the cellular behaviour, gene expression and their potential to make a distinction between different types of cells.

Sequentially in regard to the advantage of reprogramming specific genetic materials, it is necessary to model processes to encourage pluripotency in the alterations of the genome, and it structures. By reprogramming neural cellular materials with the human body and creating iPSCs from human neural stem cells lacking the presence of specific viruses, the scientists developed new understanding of the function of iPSCs. --Joe Nassif 13:33, 8 October 2009 (EST)

Question 2. What approach / method did the research team take to tackle / improve the problem? (z3255007)- Sadaf Masood

Introduction of Viral-free, integration free reprogramming approach, where pluripotent factors Oct4 and Nanog were cloned and transferred into human fetal neural progenitor cells under high frequency, which when expressed itself, became human iPSCs. This is also considered a safe approach in clinical terms as virus will not be affecting the genome.

Question 3. What was the breakthrough / major advancement OR failure / drawback? and why might this be of significance?(z3126345) Gary Liu

while both mouse and human iPSCs have been shown to be similar to embryonic stem cells in terms of cell behavior, gene expression and their potential to differentiate into different types of cells, researchers had not achieved a comprehensive analysis to compare iPSCs and embryonic stem cells.

"One reason is that previous methodologies used to derive iPSCs weren't 'footprint free,'" Muotri explained. "Viruses could integrate into the genome of the cell, possibly affecting or disrupting genes."

"In order to take full advantage of reprogramming, it is essential to develop methods to induce pluripotency in the absence of permanent changes in the genome," added Fred H. Gage, PhD, a professor in the Laboratory for Genetics at the Salk Institute and the Vi and John Adler Chair for Research on Age-Related Neurodegenerative Diseases.

Question 4. What are the next steps in moving forward? What are the next or new hurdles to overcome? --Sando Rashed 14:15, 8 October 2009 (EST)

they have been able to find out that there is a safe way to create induced pluripotent stem cells, but what they are able to research now is that do these cells they have created have a issue with there memories is it affected by using a viral free method.

Constructive Criticism of Coordinator

--Mark Hill 08:07, 8 October 2009 (EST) The following comments are general in nature in no specific order, as it would be inappropriate to suggest specific changes and then assess the final project. Comments will be added during this week and you still have one week before final submission.

  • File:Fertilized_and_Unfertilised_Eggs.jpg File:Egg_Development.jpg what is the original source that these images are based upon? There is no description on the image page when it opens of what the images are showing.
  • Some figure legend titles could be tidier.
  • There is no list of changes that have been made in response to peer review process.
  • The stage images you have begun to add to your project are from Xenbase - stages it is incorrect to give UNSW Embryology as the source as my page just provides links to this external site. "Digitized images and developmental data from Nieuwkoop and Faber (1994) Normal Table of Xenopus laevis (Daudin). Garland Publishing Inc, New York ISBN 0-8153-1896-0." you will need to get permission to use these images in your project.

Constructive Criticism of Peers

--Sally Clarke 10:12, 1 October 2009 (EST) Great Assignments guys

- Great use of images

- It jumps straight into the information which can be either a good and bad thing depending on what you are trying to achieve, maybe add in an introductory section which leads the reader on to the next bits of information

- is the anatomy section of the Frog Necessary - remember what we are studying here!!!

- The staging section is good except that you only link to the images - would you be able to have thumbnails of each of them in the table - it would help the information

- Wiki Pages??? Maybe not

- Try to make your information a little more succinct as you repeat information in the timeline and staging sections and remember formatting - history section etc.

- Include the information on why this model is used - advantages and disadvantages of this model maybe

- Current research is good but you should probably include some info on the genome - or a link to find out information about it

Overall its a great project!

--Bronwyn Lewis-Jones 09:06, 1 October 2009 (EST) This is a great assignment. Congratulations. Well set out and good use of applicable images. I think the most important change to make is to include an introduction which gives the reader a brief understanding about the frog (the anatomy section does a good job of this but maybe include a few sentences in an intro) and why it is used in embryology research. Also you could be more specific with your image labels (e.g. "Typical Frog" - why not give us it's biological name if possible). I think you could also cut back on some unnecessary information in the timing/staging section(s). Also it might be a good idea to remove the signatures to allow the reader to focus on the information. Hope you find this helpful. :)

--Julianna Lam 01:39, 1 October 2009 (EST) great work guys.

- history section is lacking information

- the maturation phases are too detailed and i dont think that much detail is required.

- staging and timeline is excellent. it could look better if there were more pictures added into the staging part.

- the glossary is very helpful

--Begum Sonmez 22:49, 30 September 2009 (EST) Hello Group 5. I'd like to start off by saying that the effort you all have put into you page is impressive. The first thing I noticed was the background information on the frog such as the embryology, growth and development, anatomy, and the egg of the frog. I found this extra information informative, interesting, and due to the lack of text,easy-to-read and engaging. The video under 'The Egg' depicting Early cleavage was an interesting video. I like how it wasn't placed under timeline or stages. The reason is because timeline and stages already has enough images, and this short and simple video provides an introduction to development.

  • You all might have noticed there is a problem with the formatting of the History section (the text needs to be 'pulled down' below the image 'Early Development of Frogs'. The same problem is found under the sections 'Abnormalities of the Frog', and 'Current Research'.
  • I think the sentence strucutre, and punctuation of the History section should be looked at. For example, '1851 - Henby Nelson(MD): He identified a remarkable fact through frog embryo. Henby observed the first cleavage of the yolk, in the egg of the frog. And corresponds in its line of direction to the longitudinal axis of the body of the embryo of those animals;' should read:

'1851 - Henby Nelson(MD): He identified a remarkable fact through the frog embryo. Henby observed the first cleavage of the yolk in the egg of the frog. And (what? The Yolk?) corresponds in its line of direction to the longitudinal axis of the body of the embryo of those animals (of what animals?). This is just something small that should be worked on just to make more sense, but the amount of text you included is good.

  • Under Gametogenesis, the sentence 'Gametogenesis is a progression which frog gametes are established from cells, called germ cells.' should read 'Gametogenesis is a progression in which frog gametes are established from germ cells.' Again, this is just a small amendment, but it will still be effective.
  • Good pictures under 'Egg and Fertilisation' and under 'Gastrulation'.
  • Under Gastrulation, the sentence 'In frogs, metamorphosis is related with to the modifications and adaptations as a frog changes environmental habitats from an aquatic to a terrestrial mode.' should read 'In frogs, metamorphosis is related with or to the modifications and adaptations occuring or taking place as a frog changes environmental habitats from an aquatic to a terrestrial mode.'
  • Too much unnecessary text under 'Maturation phases'. Try condensing the text under '4. Fertilisation of the egg' and '5.Segmentation of the Egg'.
  • There is a good amount of information under the 'Structures derived from Germ-layers of frog species' section. It can be improved by listing (in dot form or numbering) the structures instead of including them all in a paragraph. I really liked this section. To the artist of the drawings: great work. I found them really helpful and relevant.
  • Under 'Current Research', try to include dates for 'Transgenesis techniques for functional genomics in Xenopus' and 'Verification of messenger RNA'. Also, is there a specific example of a current research under the sub-heading 'Cell Cycle'. This would be more resourceful for the reader.
  • The glossary was helpful.

Overall, well done on your efforts Group 5. The pictures are a great asset to this page.

--Angama Yaquobi 22:01, 30 September 2009 (EST) Congratulation all the team members of group 5, the page looks amazing. Very well researched. So far one of the best looking page with alot of informative content.Great images used throughout the entire page especially in the section of the growth and modification of frog species.However i suggest few changes can make the page look even better

  • Lack of information in the section of history.
  • There is too much information in the maturation phase which can be concised to make it much more easy for the readers to acquire the important information.
  • For the section of current research more information is needed to give readers a more in-depth knowledge of the current research done on the model.

Overall well researched page. Well done guys. cheers.

--Jenny Guy 19:01, 30 September 2009 (EST)


  • The a specific breed of frog used? Or are many types used for embryological research? This should be stated in the introduction. The image youve used from wiki is fine except its a "typical frog"...what is this? are you forming your page based on this frog?
  • I dont believe the anatomy of the frog needs to be stated. We're researching the embryology, and yes this is going to be different to the human, so state the differences that cause embryology problems. Obviously we're going to be different but if you want to state that the frog only has 3 chambers, state that heart research wouldnt use a frog model since its not similar.
  • Need to do some formatting - history heading is misplaced, i almost missed it.
  • There is a hell of a lot of information to digest for the fertilisation. Would it be possible to cut some of this down? Select the best parts?
  • Stages is very plain. Enough said.
  • The image of the frog it in the wrong spot? Shouldn't it be put close to the skeletal abnormalities paragraph - and refer to the image, and not the infectious diseases section.
  • In genetics, can you explain why frogs have different numbers of chromosomes. Does this mean that some breeds of frogs can mate because they would have ill adapting chromosomes? How does the chromosomes it does have relate to human chromosomes??
  • i got very confused with the subtypes of families of the embryological research affected with modern or primative frogs?
  • Has the genome been sequenced? Apparently so? Some of the english here needs to be editted. Grammar isnt good, some sentences dont make too much sense.
  • Have you listed "links to related resources/research laboratories?" like Mark asked for in the marking criteria?? nope.

--Gabriela Pinget 14:36, 30 September 2009 (EST) Hello! Nice page! Mind if I criticise?

- I like the use of the anatomy of the frog to better orientate the reader. Although it is slightly superflous, it does not contain too much information to look out of place,so it looks good

-Maybe in the intro you should add a little info on why it is a model for embryological studies i.e. its advantages over the others

- I like the clear structure of the history section. It makes it very easy to read and understand.Although, the poor grammar makes it a little hard to understand (e.g. you may want to re-word what you wrote for 1976, it reads as though a woman was impregnated with a frog)

-perhaps there is a little too much detail on the growth and development of the frog. It's a little overwhelming- also quite a bit of repetition in this section

--Mitchell Mathieson 09:32, 25 September 2009 (EST) I think the looks good. However, the information is very spread out all over the place, and there is a bit of irrelevant information, such as the anatomy of the frog. There also seems to be repeated information in the stages and timelines; such as having tables and text to say the same thing. There was a heavy emphasis on the stages of development (it pretty much takes up 3/4 of the page) which probably could have been done more succinctly. The formatting needs a bit of fine tuning (heading separated from their text, and gaps everywhere), but in general it is good; the information is quite useful and well written.

--Elide Newton 14:57, 26 September 2009 (EST)HELLO GROUP 5: Well done on your assignment. my one piece of advice on your assignment is all about improving the flow and purpose of your assignment. Firstly There needs to be a introduction to the frog. why the frog is used as a model for embryology? By understanding the stages of development and timeline of the frog we can study the frog as a model. Why it is a good model and our understanding can be linked to why is has been used in the past and why it is being used currently in the future. hopefully this introduction clarifies the purpose of your information, and gives an outline to what you will cover in the assignment. also there is lots of unimportant information in regards to this assignment which is clouding your purpose of timeline, stages, genetics, past, present and future research. with this introduction paragraph, stating what topics you will cover and how these fit into using the frog as a model for embryology, hopefully it will flow better. all the best!

--Jin Lee 16:32, 26 September 2009 (EST) congulatulation Group5. The assignment looks good however, if you can make some additions it will be even better. Here is my suggestions: firstly the reference needs to be looked after. secondly some of sections are irrelevant(I found the 'anatomy of the frog' is irrelevant) and too much general information about the frog. May be better to focus on the assignment cirteria. For the history section, information is lacking(it's too brief) may be trying to add some more details about the each in 1976, please mention which doctor you are reffering to. For the current research section, some more information needs. Overall, the assignment is visually well represented but may be concentrate on the main sections like timeline, stages, genetics, history and current research.

--Vishnnu Shanmugam 21:37, 26 September 2009 (EST)Great work frog group. The assignment you have put together is informative and well organized. One of the best features of the project is how clicking on the image takes you to another page with detailed and thorough explanations of the image. It is also good to see that you have added extra sections such as “abnormalities of the frog” and “the egg”. I note that too many groups are only interested in the headings specified in the marking criteria and have not done any extra work. The glossary is also a nice touch. Ways of improving the assignment:

- The background section introducing the frog needs to have information on why the frog model is useful. Include information on spawning, maintenance of specimens, genetic attributes and genetic similarities with humans.

- Although the addition of extra sections is good, it needs to be relevant to embryology. The anatomy of the frog section concentrates on the anatomy of the adult frog which is irrelevant for this project.

- The assignment should contain links to research laboratories and researchers as specified by the marking criteria. The external links do not do this.

- Remove the signature and time stamping at different sections of the assignment. The group project is collective effort, and the final presentation should not look like it has been split up. Do not worry about your contributions as these are logged and available for viewing under the “my contributions link”

- Some links in the text transfer you to Wikipedia pages on the frog....these should not be used as a source of information in academic projects.

- The assignment needs to be properly referenced as there are no references made in the actual text. see for help with APA referencing

Overall a good project, some changes and additions are necessary to make it outstanding.

--Emily Wong 11:06, 27 September 2009 (EST) Firstly, Great work group 5. This project is very informative, well structured but a little unorganized. There is an extremely large amount of text presented. Perhaps a few more pictures or diagrams to negate some of the written work would be a way to improve the project. The work is well referenced with an extensive reference list. There is a lot of information on content that is not required. A way to improve your project would be to summarise a lot of this unnecessary information and maybe try and place it under one of the content headings. It appeared that a lot of this information was about stages or time points so maybe you could include this information in one of those sections.

--Thomas Dangerfield 14:25, 28 September 2009 (EST)Hey guys! Nice job! Plenty of information present, it just seems to jumble around a lot. Definitely needs an introduction, and possibly the first available section could be moved to after the anatomy of the frog. I don't mind the basic anatomy of the frog by the way, as it provides a little background to what the reader is going to end up with at the end of the development stage. Also the images could have a caption about what is actually happening in the image or what the images are trying to describe. There also seems to be a whole of a lot of information and plenty of images on the development and growth of the frog, but comparatively little on the genetics section. Chromosome maps can be very handy and comparisons with the human genome can help establish a picture of what you are trying to say. Just some organization and possible sifting of information would do the assignment nicely! Still, a very nice job on the frog guys!

--Sumaiya Rahman 17:16, 28 September 2009 (EST) Hey guys! Wow congrats on the assignment. I actually like the extra topics on the page. It makes it interesting and gives a lot of background knowledge to the reader. As mentioned, i am not sure why you have put in your signature stamps, this is not necessary. A lot of good images have been used but maybe instead of using figure 1, figure 2 etc. under the images; you could write what the image actually shows. I think this is what we were told to do? The links to the images in each stage are really good and help convey the information. The other thing that would help improve your page would be the addition of a glossary. Well done overall!

--Carly Mooney 11:56, 29 September 2009 (EST) I think this was the assignment that looked the most professional. I liked the additional anatomy of the frog section, Few suggestions:

  • a proper paragraphed introduction
  • perhaps either in introduction of the history of the model needs a small explanation of why you use the frog as a model.
  • remove the signatures, it is distracting and looks like it wasn't a group effort
  • some sections were well referenced and others not, this needs to be unified.
  • I think some of the sections with single images can afford to have those images enlarged slightly.

Overall this assignment looks the most unified of them all so congrats.

--Joanne Raffel 16:41, 29 September 2009 (EST) Well researched page. I would recommend including an introduction, which would make a better transition into the next section, also the growth and development, the egg and the anatomy section could have been condensed into one section. I thought there was too many main headings, I would recommend including subheadings, otherwise the information seems disjointed. I also got very confused reading through the page as I wasnt sure which heading was apart of another or whether it was something completely new. The history section was well formatted, however more information would have been appreciated as there didnt seem to be much of the actual history, more of a timeline of the frog. I thought the gametogenesis section was irrelevent. I also didnt need to know who wrote what section, this is a group assessment. Some of your headings could have been phrased more appropriately and clearer. The egg and fertilisation section would have been more impressive with subheadings rather than continuous main headings, whereby allowing the information to flow, also some of the information wasnt introduced in each section, it was just assumed. The maturation section would be better formatted in a table rather than a chunk of text. Cleavage, gastrulation, growth and modification, germ layer origin and structures derived from germ layer would be better as one section rather than multiple. The life cycle was extremly short and lacked information. The timeline was well formatted however I would have liked pictures. The staging section was organised clearly, however I would have liked to have seem part of the image rather than having to see it via the link. The abnormalities and genetics section would have been clearly as paragraphs with more information describing what is occuring rather than listing it, pictures would also be appreciated if possible. The current research section covered a number of topics however each section was very short. The glossary was appreciated however some of the words werent necessary (i.e. aquatic). Overall a very good page with some interesting images.

--Mark Hill 01:50, 8 September 2009 (EST) Still coming along, you have a lot of interesting pieces of information and some fair images. But how do the images relate to the text and where is the linkage? It is always easier to paste a whole lot of text information without interpreting what it actually means. Some of the information is good, tough some text also looks to be sourced without referencing. Overall the page lacks an integrated feel and structure.

--Mark Hill 08:45, 21 August 2009 (EST) This is a good start. It is important that the project page content/structure reflects what all members of the group have in mind. There should be a list of relevant references now on this discussion pages.

Background Reading

--Sadaf Masood 21:44, 8 September 2009 (EST) This link is for you Gary

--Gang Liu 15:18, 23 September 2009 (EST) hi could anyone tell me how to upload pictures on the main page. i'm trying to upload pictures from this link, into the last column of stages of frog embryo table. cheers!

Hey guys!!

I have only met one person in the group..and that was today in the lecture (3/08/09)

Still missing out on the third person here!

Lets decide on the animal guys before the lab!!!!


--Gang Liu 15:22, 16 August 2009 (EST)Hi all, I'm Gary and i've just enrolled into this subject mid-week last week. Will try to catch up with the group assignment and individual homework.

--Gang Liu 14:54, 19 August 2009 (EST)Hi group, since we are dividing the assessment. I would like to work on sections such as "The egg", "Fertilization", "Cleavage", "Gastrulation", and "Hand-drawing diagram". Thank you.

--Gang Liu 12:56, 20 August 2009 (EST)Hi all, Joe is working on the first six subheadings. And i'm happy to take whatever subheadings the rest of the group is not working on. Thank you.

--Gang Liu 14:07, 20 August 2009 (EST)Hi all, after this week's group dicussion in the lab, we split the tasks as the following:

  • Joe is responsible for subheadings such as egg, fertilization, cleavage, gastrulation, differentiation and growth;
  • Gary is responsible for subheadings such as anatomy of frog, timeline and stage(introduction;
  • Sando is responsible for subheadings such as reproduction(male and female)+random subheading;
  • Sadaf is responsible for subheadings such as abnormalities, current research, genetics and glossary.

--Gang Liu 17:26, 23 August 2009 (EST)Hi all, should we mention Xenopus, part of frog family? --Gang Liu 09:29, 27 August 2009 (EST)Please ignore this line

--Gang Liu 18:00, 26 August 2009 (EST)Joe, thank you for updating our group page. Will upload my contents as soon as possible.

Hey guys, i need the list of words for the glossary or do u want me to pick them out myself? thanks!--Sadaf Masood 10:47, 27 August 2009 (EST)

--Gang Liu 11:24, 27 August 2009 (EST)Hi, sadaf, will upload my glossary by tomorrow. Thanks.

--Gang Liu 11:30, 27 August 2009 (EST)Hi group, i just realised there is no one doing history part. Is there anyone would like to take this part? Or else, i'll work on it. Let us know.

sick website

EGG: --Sando Rashed 18:17, 23 September 2009 (EST) as late as im posting this i havent had time this past week to upload my notes but im putting them up now

--Sando Rashed 18:18, 23 September 2009 (EST)Gastrulation of a frog embryology An invagination of cells that is found in the area of the embryo where it occupies the middle of the gray crescent, this is the beginning of gastrulation. This beginning is what creates the blastopore which in the future will become the anus, and a group of cells that would later on produce the notochord which will eventually become the backbone (also known as the speeman organizer). Stimulates the ectoderm to form neural tissue (rather than it forming skin), so it begins the staging of the neural folds, which eventually the tips of the folds will form the neural tube which will become the spinal chord and the brain. During gastrulation three layers start forming, these layers are known as the ectoderm, endoderm and the mesoderm. Layer Forms out of it

Ectoderm which may form the Brain, skin, spinal chord

Mesoderm which may form the Notochord, muscles, brain

Endoderm which may form the Inner lining of lings, bladder, thymus forms here.

--Sando Rashed 22:24, 23 September 2009 (EST)Cleavage = the repeated division of a fertilised ovum When the zygote nucleus forms the first cleavage forms, this nucleus undergoes a number of mitosis processes, a wrinkle forms down longitudinally passing the poles of the eggs where the sperm enters. This is how the egg is split up into two halves and this process is what forms the 2-cell stage. The process of the second cleavage is the process that allows the 4-cell stage to occur, the wrinkle runs through the poles at right angles instead of running through it longitudinally. The 8 stage cell is formed during the third cleavage it cuts across horizontally but it cuts through closer to the animal poles rather than the vegetal poles. As cleavages continually occur a 16 and 32 cell embryo are formed, and as these cleavages continuously occur the cells closer to the animal poles divide more rapidly and in more numbers compared to the vegetal pole. Eventually with all these cells continuously forming the blastula forms and a blastoseal which is a fluid filled cavity forms within it (no growth of the embryo has formed). --Sando Rashed 23:06, 23 September 2009 (EST)Anatomy of a Frog

The anatomy of a frog has many specialized features that are unique to the frog to help them live in their environment, they have long sticky tongues that help with them to grab food, they have specialized bones in the legs to help them jump. When under water frogs are able to breathe through their skin, the oxygen is able to diffuse straight into the blood through the pores on the skin; they also have lungs that allow them to breathe on land. In frogs they have 3 valves instead of the 4 valves in humans, they have one ventricle and two atria’s, the spiral valve does not allow blood with oxygen to mix with blood that has no oxygen. Frogs are able to listen to sounds that have a low pitch through their skin as well as hearing sounds with a high pitch through their ears.

The Egg

The egg of a frog is approximately 1.6 million times larger than a normal frog cell. While all the embryological development is occurring through time it will eventually become a tadpole. The egg can be divided into three different regions, the top part of the egg is known as the animal pole, the bottom half of the egg is known as the vegetal pole and a segment between the animal and vegetal pole is known as the gray crescent.--Sando Rashed 10:09, 24 September 2009 (EST)


This occurs once the sperm cell has inserted, following the insertion of the sperm cells meiosis II is completed, there is a 30 degree position change of the cytoplasm, gray crescent allows this change to be visible in some amphibians, the gray crescent is able what determines the expect ted outline of how the frog will form. The sperm cell joins with the nuclei of the egg which forms the diploid zygote nucleus. --Sando Rashed 10:09, 24 September 2009 (EST)