Zebrafish - Zygote Period
The duration of this period is from 0 to 0.75 hours
- It is here that there is a transition from one cell to two cells
- Fertilisation occurs activating cytoplastimic movement
- The animal poles within the cell segregate the blastodisc from the yolk cytoplasm
- Segregation continues into the Cleavage Period
Here cytoplasm moves toward the animal pole to form the blastodisc, which is where future cell divisions will occur. The blastodisc then divides into 2 cells and this division continues occurring well into the cleavage stages.