Zygote and Embryo

Zygote refers to the fertilisation process during which male and female gamete unite. In simpler words, the zygote is fertilised egg produced from the union of a female ovum and male sperm. This stage is very short as it is further segmented into cells of smaller size. The zygote contains all the information related to the living organism’s genes. Both the male and female sperm contribute equally. On the contrary, an embryo refers to the early developmental stage of a multicellular organism. Embryo development starts after the fertilisation stage and continues until body structures are formed. 

Zygote

The contact of sperm and egg fusion takes place, resulting in fertilisation. Sperm nuclei and eggs fuse into a singular nucleus in the fertilisation process. After which, the fertilised egg is formed named a zygote. The term zygote originates from a Greek word named “zygotes”, of which the English meaning is combined or to join.  

A zygote is the first developmental stage of any organism. Since it is developed from parent cells, it contains genetic information, which is essential for organism growth. It transmits all the genetic information during embryo development. This is why a baby looks similar to a father or mother. Since the zygote takes the equal contribution of genes from parents, the baby is not a carbon copy of any parent.  

During the transmission of information zygote, a process named mitosis. It is the process of cell duplication, which includes the subdivision of cells of identical genes. Mitosis helps the zygote in its conversion into an embryo, through which it enters further developmental stages. 

Embryo

In medical terms, the embryo is called a diploid eukaryote. Many textbooks claim its derivation from the Greek word ” embryonic”, which means fetus. On the contrary, some authors claim it is derived from a Latin word named “embryo”, which means growth.  

After the fertilisation of the zygote, the embryo begins its developmental stage. The embryo is formed from zygote division through the process named embryogenesis. After sexual reproduction, the embryo is in the second developmental phase. The embryo grows until birth, embarking on the continuous division of cells. 

The embryo developmental stage is different amongst the animals. The embryo develops from unborn hatches. Thus, a fertilised egg is further subdivided into cells known as pre-embryo. Hence, within animals, the embryo undergoes different fertilisation processes.

It continuously divides itself into cells, and balls which further develop into tissues and body organs. The development of structure is known as an embryo. It is further embedded within the uterus wall, where further development occurs. The further development of the embryo takes place in body parts of legs, heads, ears, and eyes. This stage of embryo development is found in the foetus. 

Zygote and Embryo: Differences

Zygote and embryo are two different concepts, although they are interrelated concepts. The processes involved in zygote and embryo lead to fetus formation. Fetus development usually takes a time of nine weeks. In the nine weeks, different organs are developed like nails, fingers, and others. After conception, zygote and embryo development takes place.

Conclusion 

Zygote refers to the original cell, which is created after forming a new organism. The cell is formed through sexual reproduction. Unification of two different gamete results in the formation of a zygote. After the fertilisation of the zygote, embryo development takes place. 

The embryo is a second developmental stage after sexual reproduction. Both embryo and zygote occur after the unification of male and female gamete. Although they both are different. A zygote is the first developmental stage, hence containing gene information from both parents. Embryo development only starts after fertilisation of the zygote and continues till the baby is born.