Difference Between Zygote and Fetus
What is a Zygote?
A zygote is a single-cell organism that is formed when a sperm fertilizes an egg during the process of conception. It is the earliest stage of human development and contains the complete set of genetic material that will determine the characteristics of the individual.
Examples of Zygote
Examples of zygotes include the fertilized eggs in the fallopian tube before implantation occurs and in vitro fertilization (IVF) embryos produced in a laboratory for assisted reproduction.
Uses of Zygote
Zygotes are used in various scientific and medical research studies to gain a deeper understanding of early human development, genetic disorders, and fertility treatments such as IVF.
What is a Fetus?
A fetus is the developing stage of a human organism that begins from the 9th week of gestation until birth. It is the period when all major organs and structures are formed, and the baby starts to grow in size and complexity.
Examples of Fetus
Examples of fetuses can be seen in ultrasound images where the baby’s features and body parts are more recognizable, and its movements can be observed.
Uses of Fetus
In medical terms, the fetus is monitored during prenatal care to check for its growth, detect any potential abnormalities, and ensure the well-being of both the mother and the developing baby.
Differences Between Zygote and Fetus
| Difference Area | Zygote | Fetus |
|---|---|---|
| Developmental Stage | Zygote represents the earliest stage of human development. | Fetus represents the later stage of human development. |
| Cellularity | Zygote is a single-cell organism. | Fetus is a multi-cellular organism. |
| Growth | Zygote undergoes rapid cell division and growth. | Fetus undergoes organ development and growth in size. |
| Appearance | Zygote is microscopic and not visible to the naked eye. | Fetus becomes visible during ultrasounds as the baby’s features form. |
| Viability | Zygote is not viable outside the womb. | Fetus becomes viable and can survive outside the womb with medical assistance from around 24 weeks. |
| Stage of Pregnancy | Zygote occurs in the early stages of pregnancy. | Fetus occurs in the later stages of pregnancy. |
| Dependency | Zygote is completely dependent on the mother for nutrition and protection. | Fetus starts to develop its own organs and become less dependent on the mother. |
| Movement | Zygote does not have any recognizable movement. | Fetus starts to exhibit movements, such as kicking and turning. |
| Size | Zygote is significantly smaller in size compared to a fetus. | Fetus grows in size and becomes much larger compared to a zygote. |
| Brain Development | Zygote has not yet developed a fully functional brain. | Fetus undergoes significant brain development during the later stages of pregnancy. |
Conclusion
In summary, a zygote is the single-cell organism formed during fertilization, representing the earliest stage of human development. On the other hand, a fetus is the developing stage of the human organism from the 9th week of gestation until birth. They differ in their developmental stage, cellularity, growth, appearance, viability, dependency, movement, size, and brain development.
People Also Ask
Q: Can a zygote survive outside the womb?
A: No, a zygote needs to implant in the uterus to develop further.
Q: At what stage does the fetus start to move?
A: Fetal movements are typically felt by the mother around 18-25 weeks of pregnancy.
Q: How does the size of a zygote compare to a fetus?
A: A zygote is significantly smaller in size compared to a fetus, which grows in size throughout pregnancy.
Q: Is the development of a zygote and fetus the same for every pregnancy?
A: While there are general stages of development, each pregnancy can have variations in the growth and development of the zygote and fetus.
Q: Are zygotes and fetuses used for medical research purposes?
A: Yes, zygotes and fetuses are used in scientific and medical research to study early human development, genetic disorders, and reproductive technologies.
