What features must an organism possess at some stage in development to be a member of phylum chordata?

Answer 1

There are three subphylums in Chordata. Two of them are invertebrates - Urochordata (tunicates) and Cephalachordata (lancelets), while the third is Vertebrata (vertebrates).

This phylum includes all animals which have a hollow dorsal nerve cord and a notochord at some stage during their development. In the case of vertebrates, the notochord is present in the embryo, and develops into the vertebral body. In the tunicates, the adult form no longer has the notochord.

Another characteristic they share is that, at some stage during their lives, they have pharyngeal grooves and pouches that develop into other essential parts of their anatomy (many textbooks still state that all vertebrate embryos have gill slits, but there has been a great deal of development in the science of embryology to refute this claim).

Chordates all have a post-anal tail, which means an extension of the notochord and nerve chord behind the anus, although this feature is no longer present in the mature forms of some creatures such as frogs, and some mammals such as people.

Chordates also have a closed circulatory system, although not all Chordates have an actual heart like the vertebrate Chordates do. They have chevron shaped musculature; are deuterostomes, meaning they have two openings to the alimentary canal, and have three coelomic (body) cavities.

Answer 2

To be a member of phylum Chordata, an organism must possess a notochord, a dorsal hollow nerve cord, pharyngeal slits or pouches, and a post-anal tail at some stage in its development. These features are present in chordates at some point in their life cycle, although they may not be present in the adult form in all species.

Answer 3

Alls it needs is a spine

Plato users the answer is D. Both A and B