Introduction
During this essay, the features of embryonic development are analysed and comparisons between the developments of different species will be explored. Developmental biology is the study of the activity which leads to the growth and maturation of organisms.[1]
The Red Jungle Fowl (Gallus gallus) is thought to be the ancestral to the modern domestic chicken. (Fumihito et al., 1994). [1] Chickens have had a long association with man, according to D. Burt 2007, domestication took place 8,000yrs ago in Thailand. [4] The chicken (Gallus gallus domesticus) is used as a model organism, it has many features which qualify it for this role. Fertilized chicken eggs (therefore embryos) …show more content…
Eighteen somites (pairs), somites are divisions of an animal’s body containing the same internal structures. They are made up of paraxial mesoderm, paraxial mesoderm is the area of the mesoderm in the neurulating embryo which is produced with the neural tube. Somites later subdivide into sclerotomes, myotomes and dermatomes. [9] In figure 2 the otic vesicles can be seen, one is visible, the other is denoted only by a slight protuberance. The neural tube can also be seen, this has developed from the neural plate and will go on to form the full central nervous …show more content…
The heart in figure 2 is not in the expected location for an adult chicken. However, in eye development shown in figure 2 the optic vesicle can be seen, it is on the rostral side of the head. In figure 1 the embryo has curled over, however the eye has remained in the same area on the head, as the embryo develops into an adult the eye does not move in relation to the head. As development moves from the anterior end of an embryo to the posterior end, in general, the closer a structure is to the anterior end of the embryo the earlier it will develop and therefore the bigger it will be. This can cause confusion when asking why features in the embryo are not in the expected adult