Female Ocellated Wrasse

Furthermore, to measure the toll that incubation takes on a male, Masonjones built a tiny respirator that records oxygen concentrations in water flowing into and out of a chamber. Before a male took on eggs, she checked his baseline need for oxygen. Then, she monitored the increase as the incubation progressed. The male's body had to work hard by the end of incubation, consuming almost a third again as much oxygen as he did before mating. To correct for oxygen used by the growing brood, Masonjones managed to keep ¼ inch-high premature seahorses alive outside the pouch so she could measure their oxygen needs. Although they undergo weeks of incubation, males directly contribute only half as much energy for offspring as females do. [5]Therefore, they do in fact fit into the widespread pattern of the less-invested sex being the less-choosy. {text:bookmark-start} {text:bookmark-end} Adaptations The question of why it is the males who undergo pregnancy rather than the females is actually not entirely known, though some researchers believe male pregnancy allows for shorter birthing intervals, hence more offspring. When looking at which sex has the ability to produce more young if they had an unlimited number of ready and willing partners, males have the potential to produce 17 percent more in a breeding season. Also, females have "time-outs” from the reproductive cycle that are 1.2 times

Pink colored spermatozoa (sperm) were surrounded by spermatocytes (formed after meiosis of spermatogonia) and spermotigonia (precursor to sperm)

Judson contributes to onefs understanding of sex among different organisms in that she makes difficult concepts simple to comprehend. Although she uses scientific terminology, she limits it so that anyone can understand the technical information she shares. Judson also describes the types of environments in which each species and

In the sharp contrast to active sperms, female only produces one ovum cell per month, which mainly functions as a “protector” and a “nurturer”. It creates a safe and warm environment, producing nutrimental supplies that nourish the embryo. In addition, egg is so loyal that, with the help of cortical granules filled with enzyme , it forms a cell membrane that keeps other sperms from entering. Imagine that millions of agile sperms competed with others and anxiously approach to one target -- egg -- no wonder only the most courageous and intelligent one wins the battle. Battle among sperms, to some extent, epitomizes male mindset of fighting off other men. Therefore, they are naturally more active; their organs for locomotion and control are inherently more flexible in order to maximize the possibility to defeat other males.

Martin McDonald is a 31 year old man who has been diagnosed as having a low sperm count, low sperm motility, and a high percentage of abnormal sperm cells. He has been married for six years and his wife has already undergone three unsuccessful attempts at artificial fertilisation and one unsuccessful attempt at in vitro

Hotchkiss also commented about the reference value provided by Moench for sperm morphology analysis67 (<20% of abnormal forms). Although he did not disagree from Moench, he argued: ‘In an incomplete but rather large groups of cases of proved fertility now under study I have yet to find an instance of normal pregnancy attributable to a seminal specimens with excessively large number of abnormal sperm, yet this condition is no infrequently encountered in cases of disturbed fertility.’

There is no sperm separation method that has produced high success rates of sperm separation to provide gender outcomes greater than 90% and therefore further work is needed to perfect the sex selection.

Multiple paternity within one set of eggs affects the survivability of the offspring. It has significant effects on the parental care and reproductive strategies, largely due to multiple males often defending the eggs and offspring. As previously stated above, anuran amphibians reproduce exclusively by external fertilization, so there are often “sneaker males” that fertilize eggs in addition to the paired male. In research about Kurixalus eiffingeri (commonly known as the rhacophorid frog), the effects of multiple paternity within an egg clutch was studied. A total of ten out of twenty-one egg clutches had multiple fathers, and of those ten, six had one or more attending males defending the clutch site. The tadpoles of the clutches with one or more males had a slightly higher number of tadpoles that made it to metamorphosis (Chen 2011). Again, this proves that polyandry is evolutionary favorable. If more than one male believes that he fertilized an egg clutch, he is more likely to stick around and defend those

Klinefelter’s syndrome is the most common genetic disorder found in men, an additional X chromosome giving the man a sex chromosomal pattern XXY, is the main cause of this disorder. The most common characteristics that are present in the men diagnosed with Klinefelter’s syndrome include, “gynocomastia, small testes, and azoospermia” or infertility (Mailburg, 2012, p 253). Although infertility is the most common diagnosis for this disorder, many of the men are not diagnosed until later in life, after they have failed to conceive, but with the help of intracytoplasmic sperm injections (ICSI) men are able to conceive their own biological children. Intracytoplasmic sperm injections are used in addition with in vitro fertilization, where a single sperm taken from the man is injected directly in the egg. There has been extensive research done on the best time to retrieve the sperm from those with Klinefelter’s syndrome and the possible problematic

the sperm are categorized as masculine and feminine. Finally, it seems that the end goal of

Sperm are analysed to find any abnormalities in structure, concentration, and motility (the ability to move spontaneously/actively, whilst consuming energy). If the sperm had any abnormalities it would not be used to breed, this reduces the chance of the offspring produced having undesirable phenotypes as only the sperm with the desired traits are used to inseminate. The best sperm are selected, and if they are going to be traveling to another location they will be stored in plastic straws which are frozen to -196 oC using liquid nitrogen and a sperm extender. The sperm extender is added to maintain the quality and life of the sperm, it is made up of; a cryoprotectant- glycerol is used to prevent damage to the sperm due to freezing; a buffer to help regulate the pH in the sperm due to its metabolic processes; a source of energy; and antibiotics for the sperm to kill any remaining pathogens (2). Artificial insemination in more beneficial for animals as I enables one bull to father more calves if they have better genetic make-up. Cows are also chosen to breed based on their milk production, udder structure, their body shape and strength of limbs, and in the case of cattle being breed for increased muscle mass, muscle mass. This means that only the best offspring are produced as only the cattle with the best physical traits are breed. AI is

Sexual selection can best be described by the definition given by Darwin himself. Sexual selection is “the advantage which certain individuals have over other individuals of the same species solely in respect of reproduction” (Hosken et al, 2011). Sexual selection occurs throughout the animal kingdom, where male frogs dominate through the depth of their croak, and certain peacocks reign superior based on the colour and intricate detail on their tails. They remain superior to their lesser counterparts as they bear more admirable characteristics, from which they are chosen by females of the same species.

Page 1 Child Growth and Development: "Life's Greatest Miracle" Paragraph In the video Life's Greatest Miracle, I was informed about how children are conceived, how they develop in the mothers body, and how amazing child birth can be. In the beginning it takes you through the steps of how sperm travels as for looking for an egg to fertilize. Although, in just one teaspoon of sperm there can be over 300 million sperm cells, only around 40% of them are usable. The other 60% can be deformed such as having two tales. The sperm can reach the Fallopian tube within 30 minutes, but it can be a 2 day swim just for sperm to reach an accepting egg. After the sperm that was strong enough to make it through the rough travel have met up with an egg, they

The diversity of animals is astounding, with different characteristics exhibited across extant species. Despite the vast differences, all animals share a fundamental similarity, and that is the need to reproduce to ensure perpetuation of their own kind, albeit with different methods of reproduction. Animals that diverged early from other groups, namely sponges from Phylum Porifera, are mostly hermaphroditic with individuals having both male and female reproductive organs. As animals increase in complexity and evolutionary trends lean towards cephalisation, most bilaterians develop a head where sensory organs are concentrated (Solomon et al., 2010). This allows active searching for suitable mating partners by facilitating locomotion and a greater awareness of their surrounding

Spermatocytogenesis is the male form of gametocytogenesis and results in the formation of spermatocytes possessing half the normal complement of genetic material. In spermatocytogenesis, a diploid spermatogonium which resides in the basal compartment of seminiferous tubules, divides mitotically to produce two diploid intermediate cells called primary spermatocytes. Each primary spermatocyte then moves into the adluminal compartment of the seminiferous tubules and duplicates its DNA and subsequently undergoes meiosis I to produce two haploid secondary spermatocytes, which will later divide once more into haploid spermatids. This division implicates sources of genetic variation, such as random inclusion of either parental chromosomes, and chromosomal crossover, to increase the genetic variability of the gamete.