Embryo

Embryos (and one tadpole) of the wrinkled frog (Rana rugosa).

An embryo is an animal or a plant in its earliest stage of development.

Plants

In botany, a plant embryo is part of a seed, consisting of precursor tissues for the leaves, stem (see hypocotyl), and root (see radicle), as well as one or more cotyledons. Once the embryo begins to germinate — grow out from the seed — it is called a seedling.

Animals

The embryo of vertebrates is defined as the stages between the first division of the zygote (a fertilized ovum) until it becomes a fetus. An embryo is called a fetus at a more advanced stage of development and up until birth or hatching. In humans, this is from the eighth week after outward

Stages

Morula-> blastula->gastrula.

See also : in vitro fertilization -- embryology

External links

• chart of human development (http://www.genefaith.org/ethgen/pages/databases/resources/humdevchart.html)

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