Final answer:
The term given to the fertilized ovum is 'zygote,' which then undergoes cell divisions to eventually form the blastocyst ready for implantation in the uterus, marking the onset of pregnancy.
Step-by-step explanation:
The Special Term for a Fertilized Ovum
The special term given to the fertilized ovum is zygote. This occurs when fertilization happens, which is the union of a sperm and an egg. Once the sperm successfully penetrates the corona radiata and the oocyte, and fusion of their nuclei takes place, we get the formation of the zygote. This zygote then undergoes many cell divisions, a process known as cleavage, becoming a morula and then a blastocyst, which eventually leads to the implantation in the uterine lining. This journey from fertilization to implantation signifies the start of pregnancy, and the zygote is the earliest developmental stage of the embryo which later grows into a full-fledged organism.
During its travel through the fallopian tube towards the uterus, the zygote carries out several mitotic cell divisions and eventually becomes a blastocyst. Within this stage, the conceptus is ready for the process of implantation in the uterus, marking the beginning of gestation.