Question

One feature that unites Kingdom Animalia is embryonic development, which is not found elsewhere in the Unikonta. The history of the Animalia is a story about changes in this embryonic development, resulting in changes in the physical appearance of animals with different body plans. Explain how specific changes in embryogenesis resulted in the diversity in adult animal body plans across the major clades of Animals. Make sure to discuss how the stages of embryogenesis have evolved across the Animal phylogeny and how these changes have allowed for new adaptations to arise. Spend one paragraph (and no more) discussing the role of homeotic genes in embryonic development.

Answer 1

Embryology supports the theory that every living thing has a common ancestor. That theory is evolution. The theory of evolution explains that not every feature of an ancestor's embryo is shown in its descendants. That explains why embryos develop into different species over time.

Embryonic development retraces evolutionary steps. Which means that the embryonic development of an organism follows all the intermediate forms of its ancestors throughout the course of evolution. The concept is primarily concerned with the changes that an embryo undergoes during the period of development.

Many traits of one type of animal appear in the embryo of another type of animal. For example, fish embryos and human embryos both have gill slits. In fish they develop into gills, but in humans they disappear before birth.

Homeotic gene, any of a group of genes that control the pattern of body formation during early embryonic development of organisms. These genes encode proteins called transcription factors that direct cells to form various parts of the body.