Write a 5 page paper on any topic in developmental biology or embryology.

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Introduction
For the survival of living beings and the establishment of a new generation of organisms are required the production of mature gametes through complex processes of differentiation. It happens in various ways through the various species. This paper will focus on the most common method of fertilization which is present in a vertebrate and therefore in the humans.
Fertilization (definition) “The combining of two gametes from different sexes to form a zygote, e.g., the penetration of sperm into the egg and the resulting combining of genetic material from both that develops into an embryo. The process involves karyogamy, the fusion of nuclei of both gametes, and plasmogamy, the fusion of cytoplasm. Each gamete contains a haploid set of chromosomes, with the resulting nucleus containing a diploid set of chromosomes.” (Rittner & McCabe, 2004).
Body
During the differentiation, female (ovum) and the male (sperm) gametes acquire distinct characteristics that define and determine their separate roles in fertilization.
Male gametes are mobile and must move to the ovum. In order to facilitate its mobility, sperms acquire specialized locomotion organelles, and are released of the cytoplasm excess. In this way, it facilitates of the transport mechanism, is very important. Sperms must have a means for attaching to the surface of the ovum, the penetration of the ovum and the delivery of haploid nuclei in the interior of the ovum. The process of creation and the formation of sperms are called spermatogenesis. (Alberts, Johnson, Lewis et al. 2012).
Unlike sperm, ovum does not necessarily have locomotors organelles, but they must have a large amount of cytoplasm, from which it is formed at the end of the embryo. Ovum...