Encounters: Zebrafish

Unfortunately, our zebrafish did not lay any eggs, so we were not able to observe the development of the zebrafish. I was very interested to see the development of the zebrafish, since their embryos are see through. I went online and found a youtube video of the developmental stages from zygote to the larval period.

The stages of the zebrafish development begins with the zygote period, in which the zygote reaches its morula stage and then reaches the 2 cell stage.

 

Within about 0.75 to 2.25 hours, it reaches the cleveage period where it will divide into the 64 cell stage. Meroblastic cleavage occurs in the zebrafish.

Between 2.25 and 5.25 hours, the embryo reaches the blastula stage. After the mid-blastula transition stage

Gastrulation begins between 5.25 10.33 hours. The tailbud begins to form and 2 somites can be observed.

Betwen 10.33 and 24 hours, segmentation begins to happen. This the period in which the folding of the embryo begins to occur and the formation of the somites begins to continue. The embryo begins to elongate and the neural cord and notochord continue to develop. During this stage, the dermis, vertebrae and skeletal muscle are formed as well.

The next stage that happens is the pharyngula period, which occurs between 24-48 hours. During this time period, the notochord is fully developed, the pectoral fins begin development and the cirgulatory system can be observed along with a heart beat.



The next step is the hatching period in which the olfactor palcodes are fully developed, the pectoral fins are elongated and the development of cartilage begins. This stage usually occurs between 48 and 72 hours.

The last stage of development of the zebrafish is the larval period.

VIDEO OF ZEBRAFISH DEVELOPMENT