Difference Between Frog and Chick Gastrulation

The key difference between frog and chick gastrulation is that the frog gastrulation results in a hollow ball gastrula while chick gastrulation results in a gastrula with flat sheets of cells. Furthermore, the frog gastrulation starts with epiboly while chick gastrulation starts through blastoderm.

Fertilization is the union of sperm with the egg cell. As the result of this process, a zygote is formed. The zygote divides by mitosis and produces the morula. Modula undergoes the blastula stage and then comes into the important stage called gastrulation. Gastrulation stage determines the fate of the cell. It will decide what kind of tissues should be made. A single layer of cells converts into the multilayered structure. These cell layers are the primary germ layers namely endoderm, ectoderm and mesoderm in triploblastic organisms. However, the gastrulation process differs among the species. There are differences as well as similarities between the gastrulation of different species in the animal kingdom. Gastrulation of frogs, sea urchins and chicks are well-known processes. After gastrulation, organogenesis begins.

CONTENTS

1. Overview and Key Difference
2. What is Frog Gastrulation
3. What is Chick Gastrulation
4. Similarities Between Frog and Chick Gastrulation
5. Side by Side Comparison – Frog vs Chick Gastrulation in Tabular Form
6. Summary

What is Frog Gastrulation?

The gastrulation of frogs explains the process of how frog blastula is becoming the three germ cell layers; ectoderm, endoderm and mesoderm. Frog blastula contains a cavity called blastocoel. At the vegetal pole, it contains yolk filled with big cells. And in the animal pole, it has smaller cells. Then the beginning of the development of three cell layers occurs. At the initial stage of frog gastrulation, few surface cells called bottle cells move into the interior of the embryo. This movement causes to create a dorsal lip.

Figure 01: Frog Gastrulation

By the epiboly process, ectoderm expands. Furthermore, a cavity called archenteron forms inside, hence, blastocoels becomes small. Endoderm surrounds the archenteron completely. This cavity connects to the outside through blastopore and then eventually become the anus. At the end of the gastrulation process, the fate of the three layers has determined. Blastula became gastrula. Ectoderm develops into the skin, sense organs and the nervous system while endoderm gives the digestive and respiratory tract and associated structures. Mesoderm gives skeleton, muscles, circulatory system, excretory system and most of the reproductive systems.

What is Chick Gastrulation?

Chick gastrulation is the conversion of chick blastula into chick gastrula by determining the fate of three germ layers. Blastocyte of chicken contains 32 cells. This 32 celled blastocyte then convert into gastrula by cell differentiation. The outer layer of the yolk sac starts to form new cells to the outside. After going through this process for a certain time, another new layer starts to form on the top of that. Yolk sac compresses and begins to deplete. When these events occur, a pore called blastopore develops.

Figure 02: The Development of the Chick

Cell invagination occurs thought this blastopore. The inner layer formed is the endoderm while the second layer is the ectoderm. Mesoderm develops in the anti clock direction as a sheet. All these three layers develop around the yolk sac. In the end, a small yolk sac remains in the gastrula. The fate of the three layers is decided at this stage. Ectoderm gives nervous system, eyes, feathers, etc. while endoderm forms digestive system. Mesoderm develops into a skeleton, circulatory system, muscles, excretory system, reproductive system, etc.

What are the Similarities Between Frog and Chick Gastrulation?

• Amphibians and birds complete neurulation in a very similar manner.
• The fate of the three layers is the same in frog and chick.

What is the Difference Between Frog and Chick Gastrulation?

Gastrulation is a phase of embryonic development. During this stage, single layered blastula develops into multilayered gastrula. Concerning frog and chick, the main difference between frog and chick gastrulation is that the frog gastrulation starts with epiboly and results in a hollow ball gastrula while chick gastrulation starts through blastoderm and results in a gastrula with flat sheets of cells.

The below infographic presents the difference between frog and chick gastrulation in tabular form.

Summary – Frog vs Chick Gastrulation

Gastrulation is a process in the early embryonic development of organisms during which the single-layered blastula converts into a multilayered structure known as the gastrula. Gastrulation is followed by organogenesis. During the gastrulation, the fate of the cells decides, and germ layers develop. Looking at the difference between frog and chick gastrulation, the gastrulation in frog and chick differ by several factors as mentioned above. And, the key difference between frog and chick gastrulation is that the frog gastrulation results in a hollow ball gastrula while chick gastrulation results in a gastrula with flat sheets of cells. However, the fates of the three germ layers are the same in both organisms.

Reference:

1.“Gastrulation.” Wikipedia, Wikimedia Foundation, 9 Aug. 2018. Available here 
2.Editors. “Gastrulation in Frog Embryo, Chick Embryo and Sea Urchin.” Biology Dictionary, Biology Dictionary, 27 Mar. 2018. Available here 

Image Courtesy:

1.”14740956736″ by Internet Archive Book Images (Public Domain) via Flickr
2.”14768762243″ by Internet Archive Book Images (Public Domain) via Flickr

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