What is Embryo?
[[File:Wrinkledfrog embryos.jpg|thumb|right|230px|Frog embryos]] [[File:Human Embryo - Approximately 8 weeks estimated gestational age.jpg|thumb|right|230px|This is what a human embryo looks like six weeks after [[conception]]]] [[File:Ginkgo embryo and gametophyte.jpg|thumb|right|Inside a ''[[Ginkgo]]'' seed is an embryo, with the beginnings of leaves and a stem.]] An '''embryo''' is the earliest stage in the development of a [[Fertilization|fertilised]] [[Egg (biology)|egg]] (the [[zygote]]). It is the term used for any animal or plant,<ref>technically, any [[multicellular organism|multicellular]] [[ploidy|diploid]] [[eukaryote]]</ref> from the first [[cell division]] until [[birth]], or [[Egg (biology)|hatching]], or [[germination]] in plants. In humans, it is called an embryo until about eight weeks after [[fertilisation|fertilization]], and from then until birth it is called a [[foetus]] (US: fetus). The development of the embryo is called '''embryogenesis''', and the study of embryos is called [[embryology]].<ref>{{Cite web|url=https://www.britannica.com/science/embryo-human-and-animal|title=Embryo (Human and Animal)|date=10 May 2018|website=Encyclopædia Britannica}}</ref> The development of an embryo passes through various stages: the [[blastula]], a hollow ball of cells; the [[gastrula]], migration of cells; [[morphogenesis]]; [[Tissue (biology)|tissue]] [[differentiation]], and so on. In [[organism]]s that [[sex|reproduce sexually]], once a [[sperm]] fertilizes an [[ovum|egg cell]], the result is a [[cell]] called the [[zygote]], which has [[DNA]] from each of the two parents. In [[plant]]s, [[animal]]s, and some [[protist]]s, the zygote divides by [[mitosis]] to produce an '''embryo'''. == Related pages == *[[Developmental biology]] == References == <references />{{-}} {{biology-stub}} [[Category:Biological reproduction]] [[Category:Developmental biology]] [[he:עובר#התפתחות עובר האדם]]