Written on: February 20, 2012
After proving itself to be the dominant egg among 19 other immature eggs, the egg matures and is released from the ovaries. From here, a predetermined path is set out for the egg, such that its fate will be the eventual release from a woman’s reproductive system. This can occur in two ways: either as a baby or as period.
The probably of the egg being released in the form of a baby is incredibly low, as most would be released as period in the form of a damaged egg, unfertilized egg, or dead fetus. However, let’s focus on its fate as the release from the reproductive system as a baby. In other words, let’s say this egg would encounter many sperms in its lifetime, and that once fertilized the environment would be suitable for the growth of the fetus.
Provided that there are sufficient amount of estrogen, progesterone, other hormones, and an overall healthy physiology of the system to maintain an ideal environment for the entire path of the egg’s journey, this isolates out sperms from the external environment as the only factor in contributing to the egg’s fate as being released either as a baby or as period. Obviously, the strongest and healthiest sperm must be available to penetrate the egg in order for the fate-as-baby path to happen. And this is where there are complications:
1) If all sperms are defective
This is highly unlikely, as nature has already created a very sophisticated system to make sure that there would be at least some effective sperms. This is so to ensure that life continues on Earth. However, if this was really the case then that would be too bad, and the egg would be released as period.
2) If a healthy sperm is available and it is successful in penetrating the egg
This is the ideal situation where the egg gets a perfect match with its ideal sperm. This sperm somehow has the ability to enter the world of the egg. And so the two merges, fertilization occurs, and together they grow and develop until their journey ends as a fully developed fetus that would exit the reproductive system as a baby.
(And now this is when things get a little creative, because I really don’t know the details with how the whole fertilization process occurs.)
3) If some sperms are defective and intrusive
Of course, each batch of sperms that the egg would encounter would not only include the perfect ones and the defective ones. Sometimes, there might be a sperm that appears to be healthy and strong, with the potential to penetrate the egg. But at the same time, this sperm would be toxic to the egg in one way or another. That is, perhaps the environment that it came from was toxic, so that if it would successfully penetrate the egg, it would toxify the egg. Another possibility might be that the sperm itself is the toxic. Either way, if the egg gets fertilized by this sperm, its fate would also end up being released as period, perhaps as a dead fetus. This is not ideal, and the egg would prevent this from happening.
Then what does the egg do? Once this toxic sperm starts trying to penetrate the egg, the receptors of the egg detects its toxic-ness and triggers a whole cascade of reaction to translate proteins that would strengthen the wall of the egg. While this might prevent the toxic sperms from entering, it also has its trade-off by making it difficult for the perfectly ideal sperm to fertilize the egg. And of course, if there were a lot of these toxic sperms, the wall of the egg would just get stronger and stronger, to the point that it becomes impossible even for the healthiest sperm to penetrate. Then what? The egg would just get released as period in the form of an unfertilized egg?
4) If there are toxic sperms and compromised physiological environment
If the egg was developed in an environment with insufficient hormones or some sort of compromised physiology to begin with, it would mean that its walls were already strengthened to begin with. And as a result, it would likely be more reactive to any toxic sperms that it encounters later on. Since the gametes these days are not as well-maintained by their hosts, the quality of each batch of sperms must contain a portion of toxic sperms. So when the egg-with-strengthen-wall meets these toxic sperms, its wall would just get thicker and thicker, so poor ideal sperm would never be able to penetrate and fertilize the egg anymore. Optimistically, it could be the case that the egg-with-strengthen-wall meets the ideal sperm before meeting all the toxic ones, so that the ideal sperm would just have to put in an extra bit of effort for fertilization to occur. But how likely is that going to happen? Probably not that likely. As a result, there’s a higher chance that both would end up leaving the reproductive system as period as well.
But if the eggs have mechanisms to adapt to this kind of toxic and/or compromised environment, making the ideal sperms’ lives difficult, then shouldn’t these ideal sperms also have a way to adapt too? After all, the purpose of the life of a sperm is to penetrate and fertilize one egg (unless it is in vitro fertilization where the sperm can try to fertilize several eggs at the same time). Surely they would try to find a way to break through the strengthened wall of the egg, so that they both don’t end up exiting the reproductive system as period?
1) Course on Developmental Psychobiology
2) Rants on 9gag
3) Course on Avian Biology
4) Course on Comparative World Religions
5) Course on Biochemistry
6) The Hunger Games
Published on February 20, 2012