What is the proper sequence of developing fertilized egg?

The proper sequence of development from a fertilized egg (zygote) to a fully formed individual is a complex and fascinating journey. Here's a simplified breakdown:

1. Cleavage: The zygote undergoes rapid cell division, creating a ball of identical cells called a morula.

2. Blastulation: The morula hollows out, forming a fluid-filled cavity called the blastocoel. This structure is now called a blastocyst.

3. Implantation: The blastocyst implants itself in the lining of the uterus, beginning the process of pregnancy.

4. Gastrulation: Cells within the blastocyst rearrange and differentiate, forming the three primary germ layers:

* Ectoderm: Develops into skin, nervous system, and sensory organs.

* Mesoderm: Develops into muscles, bones, circulatory system, and reproductive organs.

* Endoderm: Develops into the lining of the digestive tract, lungs, and other internal organs.

5. Organogenesis: The germ layers further differentiate, giving rise to the formation of specific organs and organ systems.

6. Fetal Development: The developing organism is now called a fetus. This stage involves significant growth and development, with the fetus undergoing major changes in size and complexity.

7. Birth: The fetus is born, marking the transition from intrauterine development to life outside the womb.

8. Postnatal Development: After birth, the individual continues to grow and develop, reaching full maturity over time.

Key Points:

* This process varies slightly depending on the species.

* The development of the fertilized egg is guided by genetic instructions and influenced by external factors.

* Hormonal changes play a critical role in regulating each stage of development.

This is just a basic overview. There are many other complex processes involved in the development of a fertilized egg, including cell signaling, gene expression, and morphogenesis. It's a testament to the incredible complexity of life and the remarkable processes that lead to the creation of a new individual.