Embryonic Development in Periplaneta Americana

Periplaneta americana, commonly known as the American cockroach, is a species of insect belonging to the order Blattodea. It is a large, winged insect that is found worldwide and is known for its adaptability and resilience. In terms of its embryonic development, there are several features present in Periplaneta americana, except for indeterminate and radial cleavage.

Embryonic cleavage refers to the process of cell division that occurs during the early stages of development in an embryo. It plays a crucial role in the formation of the body plan and the differentiation of various cell types. Cleavage can be classified into two types: determinate and indeterminate.

Determinate cleavage is characterized by the presence of cells that are predetermined to develop into specific structures. In this type of cleavage, the fate of each cell is determined early on, and the cells are restricted in their developmental potential. This type of cleavage is observed in many organisms, including humans.

Indeterminate cleavage, on the other hand, is characterized by the presence of cells that have the potential to develop into any cell type or structure. In this type of cleavage, the fate of each cell is not predetermined, and the cells have the ability to differentiate into various cell types. This type of cleavage is observed in organisms such as sea urchins and some other invertebrates.

In the case of Periplaneta americana, the embryonic development does not exhibit indeterminate and radial cleavage. Instead, it follows a different pattern of cleavage. The exact type of cleavage in Periplaneta americana is not mentioned in the given options, but it is clear that indeterminate and radial cleavage are not present.

Exoskeleton Composition

One of the features mentioned in the options is the composition of the exoskeleton in Periplaneta americana. The exoskeleton of Periplaneta americana is composed of a polysaccharide called chitin, which is a derivative of N-acetylglucosamine. Chitin provides structural support and protection to the insect's body, and it is a characteristic feature of arthropods.

Conclusion

In summary, the feature that is not present in Periplaneta americana is indeterminate and radial cleavage during embryonic development. The other features mentioned in the options, such as a metamerically segmented body, schizocoelom as the body cavity, and an exoskeleton composed of N-acetylglucosamine (chitin), are present in Periplaneta americana.