A new species of chordate is discovered. It produces a free-swimming larva that has a notochord and a nerve cord. The larva attaches to a surface and matures into a saclike adult that filter feeds. The notochord and nerve cord are not present in the adult. To what group of chordates does this new species belong?

Urochordata

Explanation:

Chordata is an animal phylum characterized by four features at some point in their lifetime. These four features are:

Chordata is further divided into urochordata, cephalochordata and vertebrates.

Urochordates display all the four features of chordates in their larval form but their adult form has none of them except pharyngeal slits. They also change from their free swimming larval form to sessile adult form which means that they attach to a surface unlike the larval form. They also display filter feeding i.e. their food is filtered via the pharyngeal slits. Since all these characteristics are being displayed by the newly discovered species, it belongs to urochordata group.

the reason the two sea urchins don't compete with each other for food, resources, etc. is because the urchins have adapted to the environment but they have also adapted to each other. this is most likely because the genes of the sea urchins.