Identical twins in humans, which are deuterostomes, are formed when cells at the four-cell stage are separated. A grasshopper, which is a protostome, will die if the cells are separated at the four-cell stage. What does this indicate about when the cells are differentiated in the zygote? Why might deuterostomes differentiate their embryonic cells later than the protostomes?

Identical twins or deuterostomes, at the four-cell stage are separated. A protostome, will die if the cells are separated at the four-cell stage:

What does this indicate about when the cells are differentiated in the zygote?

This indicates that although in both, deuterostomes and protostomes, the zygote first early four-stage stage divisions occur into a blastula or hollow ball of cells, deuterostome embryos develop into a parallel or perpendicular to the polar axis division, known as radial cleavage, w

hile many protostomes develops under spiral cleavage, this is when the protostomes and the deuterostomes start to differ.

Why might deuterostomes differentiate their embryonic cells later than the protostomes?

Because in deuterostomes display indeterminate cleavage, in which the developmental fate of the cells in the developing embryo are not determined by the identity of the parent cell. The notochord, a flexible rod structure in mesodermal cells, a structural element of chordates and of the early embryo of vertebrates, plays an organizational role in the nervous system development. In later vertebrate development, it becomes part of the vertebral column. The anus forms first from blastopore, and then followed by the mouth. This all occurs in the gastrulation stage, by the other hand in the protostomes the mouth opening is the first to be formed from blastopore, and later followed by the anus. Most protostomes are schizocoelomates, which means a strong mass of the embryonic mesoderm parts to frame a coelom, which develops through enterocoely.

Explanation:

The main difference between protostomes and deuterostomes are how they develop in the early embryo stages.

While in protostomes in the lower invertebrate phyla, the mouth appears before the anus during development, cleavage is spiral and determinate, and the coelom forms as a splitting of the mesoderm, but if the first four cells are separated, each cell is capable of forming a complete small larva; and if a cell is removed from the blastula, the other cells will compensate, i

n the deuterostomes, the oral end of the animal develops from the second opening on the dorsal surface of the animal; the blastopore becomes the anus.

Animals from both groups possess a complete digestive tract, but in protostomes the first opening of the embryonic gut develops into the mouth, and the anus forms secondarily. In deuterostomes, the anus forms first while the mouth develops secondarily.