Difference between Foetus and Zygote
The development of a human being occurs in a series of stages. Two of the earliest stages are the zygote and the foetus. Although the two terms might seem interchangeable, they refer to very different stages of human development. In this article, we will explore the difference between foetus and zygote.
Definition of Zygote
The zygote is a single fertilized cell created by the fusion of a sperm and an egg during conception. The zygote contains all the genetic information from both the mother and father, and it represents the starting point of human development. The zygote divides rapidly, generating more cells that will eventually develop into an embryo.
Definition of Foetus
A foetus is the unborn offspring of a mammal, specifically after the embryonic stage and before birth. In humans, the foetal stage begins at the end of the 8th week of gestation and lasts until delivery. During the foetal stage, the various organs and systems of the body continue to form and mature. The foetus grows rapidly, and it becomes more and more recognizable as a miniature version of an adult human.
Key Differences between Foetus and Zygote
While the zygote and foetus are both stages in human development, they are quite different from each other. The main differences between the two include:
– Size: A zygote is a single-cell organism, whereas a foetus can weigh several pounds at birth.
– Development: A zygote is just beginning the process of cell division, while a foetus has already developed most of its organs and systems.
– Timeline: The zygote stage lasts just a few days, while the foetus stage lasts for several months.
– Appearance: A zygote is too small to see with the naked eye, whereas a foetus is clearly visible in an ultrasound scan.
– Viability: A zygote cannot survive outside of the womb, whereas a foetus can survive if born prematurely, with medical intervention.
Conclusion
In summary, the differences between foetus and zygote are significant. The zygote is an early stage in human development that marks the beginning of cell division. The foetus, on the other hand, is a much more advanced stage, where most of the body’s organs and systems have already formed. Understanding these differences is important for anyone interested in human development, whether they are healthcare providers, expectant parents, or just curious individuals.
Table difference between foetus and zygote
| Characteristics | Foetus | Zygote |
|---|---|---|
| Size | Larger | Smaller |
| Development stage | Later stage of development | Earliest stage of development |
| Weeks of gestation | From 9th week onward | First two weeks of gestation |
| Major organs formed | All major organs are formed | No major organs are formed yet |
| Placenta | Fully formed | Not formed yet |
| Embryo sac | Not present | Present |