Seastars were the very first species that were shown to be a Keystone species.

Which of the following groupings of fishes have cartilaginous skeletons?

What is the function of the dermal branchiae?

The Echinoderms are one of two groups of organisms whose anus develops before the mouth in the embryo. What is the other group?

Vertebrates can be divided into two groups — those with jaws, the gnasherostomes, and those without jaws, the agnathans.

Which of the following groupings of fishes have cartilaginous skeletons?

The subphylum Urochordata is different from the other chordates in that the adults have lost most of the characteristic features of the phylum.

Write down the 5 major groups of living fishes.

There are more freshwater and terrestrial species of echinoderms than all the marine species.

Among many new features found in the early vertebrates, one involved the development in the circulatory system of a ventral chambered , and cells for transporting oxygen in the blood called