Final answer:
In embryonic development, animals are classified as protostomes or deuterostomes based on the fate of the blastopore; protostomes develop the mouth from the blastopore while deuterostomes develop the anus. Protostomes have spiral mosaic cleavage and determinate cell fate, while deuterostomes have radial regulative cleavage and indeterminate cell fate.
Step-by-step explanation:
Differences Between Protostomes and Deuterostomes
The fate of the blastopore during embryonic development distinguishes two groups of animals: protostomes and deuterostomes. For protostomes, the blastopore develops into the mouth with spiral mosaic cleavage and determinate cell fate, leading to organisms like arthropods, mollusks, and annelids.
In contrast, deuterostomes have the blastopore developing into the anus, exhibit radial regulative cleavage, and have indeterminate cell fate, which includes animals such as chordates and echinoderms.
Furthermore, during embryogenesis, the blastocoel is formed, and gastrulation takes place where the primitive gut or archenteron is created.
Protostomes form the coelom through schizocoely, whereas, in deuterostomes, it forms through enterocoely. These developmental processes reflect deeper evolutionary divergence in body plan organization.
It is essential to note that current evidence provides a more complex picture of these developmental pathways, indicating that the relationship between blastopore fate and mouth formation is not as simple as once believed.
However, these two categories still offer a fundamental framework for understanding early animal development and evolutionary relationships.