Are Humans Protostomes or Deuterostomes?

kristian sekulic/Vetta/Getty Images

Humans are deuterostomes. Deuterostomes belong to the even larger bilateria group. The bilateria group of organisms is thus named because the organisms are bilaterally symmetrical with matching left and right sides to their bodies.

A deuterostome has both an anus and a mouth, while protostomes only have a mouth. During development, the opening that forms at the gastrula’s lower end, which scientists call the blastopore, becomes the anus after development. For protostomes, the blastospore becomes the mouth after development. Deuterostomes have a mouth at the opposite end, and then the development of the digestive tract connects both of the openings. All of this development occurs during the embryo stage.