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The zygote is the earliest developmental stage. In humans and most other anisogamous organisms, a zygote is formed when an egg cell and sperm cell come together to create a new unique organism. The formation of a totipotent zygote with the potential to produce a whole organism depends on epigenetic reprogramming.
Zygosity (the noun, zygote, is from the Greek zygotos "yoked," from zygon "yoke") (/ z aɪ ˈ ɡ ɒ s ɪ t i /) is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism.
In biological terms, the development of the human body entails growth from a one-celled zygote to an adult human being. Fertilization occurs when the sperm cell successfully enters and fuses with an egg cell (ovum). The genetic material of the sperm and egg then combine to form the single cell zygote and the germinal stage of development commences.
The resulting zygote develops into an embryo, while the triploid endosperm (one sperm cell plus two female cells) and female tissues of the ovule give rise to the surrounding tissues in the developing seed. The ovary, which produced the female gametophyte(s), then grows into a fruit, which surrounds the seed(s).
The zygote then becomes implanted in the lining of the uterus, where it begins the processes of embryogenesis and morphogenesis. When the fetus is developed enough to survive outside of the uterus , the cervix dilates and contractions of the uterus propel it through the birth canal, which is the vagina , and thereby gives external life to the ...
In biology, a biological life cycle (or just life cycle when the biological context is clear) is a series of stages of the life of an organism, that begins as a zygote, often in an egg, and concludes as an adult that reproduces, producing an offspring in the form of a new zygote which then itself goes through the same series of stages, the ...
A conceptus (from Latin: concipere, to conceive) is an embryo and its appendages (adnexa), the associated membranes, placenta, and umbilical cord; the products of conception [1] or, more broadly, "the product of conception at any point between fertilization and birth."
The division of blastomeres from the zygote allows a single fertile cell to continue to cleave and differentiate until a blastocyst forms. The differentiation of the blastomere allows for the development of two distinct cell populations: the inner cell mass, which becomes the precursor to the embryo, and the trophectoderm, which becomes the precursor to the placenta.