Reproduction and development practical logbook
Observation of budding in brown hydra
Image 1: Budding in brown hydra
One of the most important processes in ensuring future generations is reproduction, which allows all living organisms to have viable offspring (McClusky, 2005). The process majorly aims at sustaining survival and evolution of the species in question through passage of genetic materials from one generation to another. Two main types of this process are sexual, which involves gametes and asexual reproduction, which is mainly concerned with regeneration of somatic cells. Sexual reproduction is the most commonly occurring in most species. It involves fusion of the female and male gametophytes to form an embryo which develops into a mature offspring of the same kind. The gametes carry coded genetic materials mostly in chromosomes which are then passed to the young one. Asexually reproduced organisms are mostly unicellular and it involves formation of daughter cells that are identical and independent of the parental organism (McClusky, 2005). Usually occurs through binary fission or by budding. In binary fission method, the parent cell divides into two and produces daughter cells that are completely independent (Bell and Wolfe, 1985) whereas in budding, the parent organism develops buds on the walls of its body. According to Berking (2002), the buds contain similar genetic materials as the parental organism cell(s). They eventually increase in size as the cells repeatedly subdivide and detach from the parent organism on maturity.
Hydra is a fresh water organism that reproduces through budding. The initial reproduction stage involves formation of a tiny protrusion on the body wall. The protrusion increases in size through cell multiplication and recruitment in the parent (Zeretzke, Perez, Velden, and Berking, 2002). Through budding, Hydra has the capability of regenerating lost limbs and delaying its aging process, thus they neither seems to undergo the normal aging process or die of old age.
Hydra’s regenerative capability plays a major role in human medicine field. They possess the capacity to self-renew their aging or diseased cells. The study and vast understanding of budding in hydra, is important in creation of great insights which might be of significant aid in human medicine especially in treating age-related complications, stem cell research or Alzheimer’s. Further research should be done to increase the applicability of the reproduction process in hydra for other medicinal benefits or fields.
Fluorescence in situ hybridization (FISH) is one of the relevant procedures in the determination of X-chromosome linked ailments, abnormalities of chromosomes, and aneuploidy screening (Choi et. al., 2009). These alterations in the gene abnormalities have been reported to lead to pregnancy loss and congenital abnormalities in the newborns. The detection of these changes is not only important to humans, but also to livestock that are bred for food. There are suggestions that these abnormalities are increasing in farm animals, which necessitates appropriate techniques that can be used to detect all cell chromosomes simultaneously to give a proper diagnosis. The FISH process is also used in the identification of sex in both the boars and cockatiel, with a similar procedure in each case. The FISH procedure is usually time consuming because of the complex cell preparation process, which limits its usage in sex determination in livestock is limited. Nonetheless, the use of FISH process in livestock is critical because it contributes research ideologies that can be used for diagnosis and development, especially in rearing economically viable animals, for example cattle, horses, birds, and pigs. There is a need for the improvement of this process to ensure that it becomes more efficient and cheaper.
The FISH process is a useful tool that scientists and framers can use in detecting some of the major genetic abnormalities. However, there is a need to address some of the disadvantages of this process, including high costs and time consumption to make it more effective. In this case, scientists should focus their attention to alternative ways of making the process better.
Sperm morphology assessment
There are scientific suggestions that the quality of sperms, including morphology and volume, have a large influence on the development of embryos (Lasiene, Gedrimas, Vitkus, Glinskyte, Lasys, Valancuite, and Sienkiewciz, 2013). In this case, there is a need for the analysis of morphology of sperms, which includes analysing the head, neck, mid-piece, and the tail. When making an assessment of the head, some of the considerations made include the size, shape, acrosomal index and vacuoles (Laisene et al., 2013). According to Laisene (2013), a normal sperm should have a nucleus that is smooth with a length of approximately 4.74 ±0.28μm and a width 3.30 ±0.20μm on average. Additionally, the neck should be straight and the mid-piece should be slender and approximately 7.5-8μm long, and should not have any cytoplasmic droplets, whose presence is an indication of immaturity of the sperm (Gadea, 2002). The tail should be straight, uniform, and slender compared to the mid- piece. In the event that these sections are folded or coiled, the sperms are said to have impaired development. All these features are important as they directly influence the capability of the sperm to fertilise the female egg (Menon, Barkema, Wilde, Kastelic, and Thundathil, 2011).
Studies about the sperm morphology are useful in the analysis of fertility potential for the male organisms (Menkveld, Holleboom, and Rhemrev, 2011). Kruger and Coetzee (1999) reported that the vital parameters measured in sperm morphology, (shape of the head, neck tail), have a great influence on the possibility of fertilisation and pregnancy rates, especially in in vitro fertilisation. Through conducting the sperm morphological studies, the chances of detecting defects or abnormalities in the sperm can be easily identified before carrying out an IVF, in which abnormal sperms are identified and isolated from the normal ones to increase the probability of fertilisation. This assessment is important such that, it helps in detecting developmental disorders in domestic animals before breeding, or during the gestation period to elevate the chances of giving rise to a viable offspring (Kondracki, et al., 2014).
The use of IVF in domesticated animals is increasing exponentially, and although it is a costly procedure, the chances of getting health and genetic disorder free offspring are high. In this case, it is clear that the studies on the morphology of the sperms are important as it is one of the sure ways of breeding healthy offspring.
Observation of vertebrate reproductive tracts and tissues
Image 2: Female reproductive tract
Image 3: Male reproductive tract
Gametogenesis is the process that ensures the development of gametes in the gonads (Desai, Ludgin, Sharma, Aniirudh, and Agarwal, 2013). This process is also known as spermatogenesis in males and oogenesis in females. These processes involve complex processes, for example, mitotic multiplication of the spermatogonia, which ensure that the resultant sperms and ova are produced normally (Philips, Gassei, and Orwig, 2010). The hormones that play an important role in regulating these processes are paracrine and endocrine. Follicle Stimulating Hormone (FSH) and Lutenizing hormone (LH), produced by the Leydig cells in the testis, facilitate spermatogenesis process by initiating the first step (Kretser, et al., 1998). LH induces the gonads to produce testosterone while FSH is raises and maintains testosterone at high levels capable of enhancing spermatogenesis occurrence (Krester et al., 1998). These hormones function well in sertoli cells simply because sperm cells lack hormonal receptors.
The oogenesis process in females start before birth, and the main part of activity is in the ovary and oviduct (Desai et. al., 2013). The process starts through a rapid mitotic division in the primordial germ cells, thereby giving rise oogonia, which forms the primordial follicles and initiates the meiotic process. Mitosis is a two-step division, which occurs in spermatogenesis and oogenesis processes, which results in daughter cells that have a haploid DNA. In oogenesis, there is the occurrence of an irregular cell division that leads to the production of an ovum with polar bodies that are extruded as the excess genetic material. On the other hand, the spermatogenesis process leads to the production of four haploid daughter cells that have similar features (Desai et. al., 2013).
Although spermatogenesis and oogenesis occur in male and female sexes, the two follow the same approach that involves two approaches, mitosis and meiosis, which lead to the production of haploid daughter cells. The major difference between the two processes is the fact that spermatogenesis occurs in males at puberty, while oogenesis occurs in females before birth. It is imperative to note that the oogenesis process results in the production of limited number of ova for the female while in spermatogenesis, sperms are produced as long as the male is sexually reproductive (Desai et. al., 2013).
Wildwood Trust workshop: Breeding Programmes
Captive breeding is a procedure in which the breeding process of animals is done in confined rather than the natural habitats of the different animals. The Wildwood trust workshop focuses on captive breeding with the aim of increasing the population of endangered species (WWF, 2007). The main objective of the program was aimed at creating a stable animal population for those species that have low chances of surviving. In this case, this program focuses on rehabilitating and raising animals to ensure that they healthy enough to survive in their natural habitats, after which they are released there. To ensure that the program is a success, there is a need for proper planning of the breeding program to ensure that the captive population is self sustaining to provide surplus animals that can be rehabilitated in the wild. In addition, enough space is required to provide a protected habitat. In this case, there is a need to ensure that there adequate funding to facilitate the program. Primack (2014) points out the importance of having effective monitoring and evaluation programs that can evaluate the progress made by the program occasionally and to make necessary adjustments to ensure that the program is effective in achieving the set objectives. Even with that, the program is forced to make major adjustments, especially in cases where the selected breeds are unable to breed in captivity.
One of the organisms this program has focused on producing is the Harvest mouse, which is probably the tiniest rodent in Britain (Micromys minutus) (Froder, 2006). One of the main advantages of this organism is that is lives mostly in marginal habitats, which are highly adaptable. The need to breed this organism is the fact that its population has reduced drastically recently because of the poor farm methods employed. Although these organisms are unwanted by the farmers, they play an important role in maintaining the ecological balance, which necessitates their continued breeding.
They attain sexual maturity at about a year old with a reproduction capacity of up to seven litters in a year, with each litter having about 8 young ones. Their mating season is usually between May and October, although it can sometimes prolong to December. The sexes are identical without dimorphism. Introducing the captive program for the mice species led to the realization of their competitive breeding, such that, and when a male and female are left alone they will not mate. They depict dominance in selecting mates before mating can occur (Froder, 2006).
The captive breeding programs is one of the effective ways of ensuring that some organisms are not extinct because of some human activities. In this case, it is correct to state that the Wildwood trust workshop is design a good job, especially with the harvest mouse, which is on the verge of becoming because of poor farm practices. Although the program faces major challenges, it is clear that it needs the support of the government and other stakeholders to make it more successful.
Cleavage and the blastula in nematodes: Caenorhabditis elegans
The cell of the embryo retracts after fertilization occurs, it separates from the zona pellucida and finally undergoes the cleavage process, and the process is a cell division that is of asymmetric form. Cleavage occurs in the early embryo, the cells are then observed to undergo a cell cycle which is often fast and simultaneous, however, according to Gilbert (2000), the cells do not experience any evident growth, and they produce some daughter cells which are different in nature. The embryos occur in different sizes owing to the axis placement. Due to different and varying number of cells, the embryos occur in different shapes and sizes during the different stages in development. Stage two of development is characterised by cells of the same size, the cells at this stage multiply at the same rate, and are quite bigger than they are in the previous stage compared to the cleavage stage. In the 3 fold stage, cells multiply with no evident increase in their size; they decrease in the membrane of the cytoplasm as it is being shared among the dividing cells which attributes to the decrease in size of the cells.
Cleavage in Caenorhabditis elegans is quite vital as it polarizes in the axes of the embryo and leads to the shape and form of the organism. Asymmetric cell division in the C. elegans is important as it helps in setting up the axes, anterior, posterior, ventral, and dorsal, of the body.