Among other functions, the Notch signaling pathway contributes to the development of somites in animals. It involves a cell signaling mechanism with a wide range of functions, including cellular differentiation, and the formation of the embryonic structures (embryogenesis). All multicellular animals use Notch signaling, which is involved in the development, maintenance, and regeneration of a range of tissues. The Notch signaling pathways spans two cells, and consists of receptor proteins, which cross one cell's membrane and interacts with proteins on adjacent cells, called ligands. The physical interaction of receptors and ligands directs the genetic response of the first cell to produce proteins that define the type of cell it will become. One of the earliest discovered roles of the Notch signaling pathway in vertebrates is in somite formation (somitogenesis). Somitogenesis is the formation of somites, which are sphere-like structures in early vertebrate embryos that are the first visible signs of segmentation. Somites then help to define many tissues and features of the adult animal's body. The Notch signaling pathway plays at least two distinct roles during somitogenesis: the first is maintenance of an oscillating protein gradient, called the segmental clock, and the second is establishing the polarity of somites. Mutations to genes in the Notch pathway can result in birth defects characterized by abnormal development of bones of the spine and ribs, like spondylocostal dysostosis. Additionally, dysfunction in the pathway linked to cancer progression, HIV-related complications, and Alzheimer´s disease, among other disorders.

The source-sink model, first proposed by biologist Francis Crick in 1970, is a theoretical system for how morphogens distribute themselves across small fields of early embryonic cells. A morphogen is a substance that determines the fate and phenotype of a group of cells through a concentration gradient of itself across that group. Crick’s theory has been experimentally confirmed with several morphogens, most notably with the protein bicoid , the first discovered morphogen. The model provides a theoretical structure for the understanding of some features of early embryonic development.

The Southern Gastric-Brooding Frog (Rheobatrachus silus) was an aquatic frog that lived in south-east Australia. In 2002, the International Union for Conservation of Nature Red List declared the frog extinct, although no wild specimens had been reported since 1981. As the common name alludes to, the R.
silus was a gastric-brooder, meaning that the female's eggs developed inside of her stomach. Weeks after ingestion, juvenile frogs escape through the mother's mouth. Because no other observed species performs this reproductive behavior, in the early twenty-first century R. silus became a target of
the de-extinction movement that aims to resurrect extinct species. Researchers studied this frog's reproductive behavior and how the eggs and embryos escape digestion. Some scientists claimed that resurrecting this frog could result in future medical applications related to digestion and to reprogramming organ function, as during pregnancy, R. silus's stomach physiologically functioned as a uterus.