An embryo (/ ˈɛmbrioʊ / EM-bree-oh) is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins …

In organisms that reproduce sexually, the union of an ovum with a sperm results in a zygote, or fertilized egg, which undergoes a series of divisions called cleavages as it passes down the fallopian tube. …

: an animal in the early stages of development that are marked by cleavage, the laying down of the basic tissues, and the formation of primitive organs and organ systems compare fetus. : a tiny young plant …

Not only do embryos get bigger during that time, but they also go from being just a simple, single, cell to being the many cells that make up a human. All of a human’s features, organs, and body systems …

Dec 3, 2025 · Early human embryo cells, once thought to be a blank slate, show abundant differences and potential for success, researchers find.

Aug 13, 2023 · In Biology, an embryo is designated as the initial phase of development for a multicellular organism arising after the fusion of a sperm cell (male sex gamete) and an egg cell (female sex …

Clicking the Carnegie stage numbers opens a page dedicated to describing that single stage and the associated developmental events. This page shows some key events of human development during …

Jul 22, 2025 · Human embryo development begins with fertilization, the union of a sperm and an egg, typically in the fallopian tube. This fusion forms a single-celled zygote, containing a complete set of …

May 21, 2024 · Embryos in animals typically indicate any pre-birth stage of development, including those in wombs or eggs. Plant embryos can take a number of different forms, though they are commonly …

Dec 3, 2025 · A new study from Caltech examines mouse embryos when they are composed of just two cells, right after undergoing their very first cellular division. This research is the first to show that …