Before human development can begin fertilization, the fusing of the sperm and the egg in the fallopian tube, must occur for it to become a zygote. The developing embryo, is called a zygote at this stage, floats down the fallopian tube towards the uterus. The first week of development is called the period of cleavage. Shortly after fertilization the zygote cleaves into 2 cells then to 4 cells, 8 cells and so on. Around the third day it’s …showed first 75 words of 1671 total…

…showed last 75 words of 1671 total…ern Genetics, Dr. Jerome Lejeune has stated, “To accept the fact that after fertilization has taken place a new human has come into being is no longer a matter of taste or opinion...it is plain experimental evidence” From this point on, every developmental stage is just part of the whole life process. From zygote to fetus and eventually to who we are today, are all the stages in human life.