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

Write down the 5 major groups of living fishes.

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

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

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

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

Ancestral arthropods have two pairs of appendages for every body segment, though more modern arthropods have often reduced that number or even increased it to several pairs of appendage per segment.

The major difference between Placoderms and Acanthodians was  ___________________________

The major difference between Placoderms and Acanthodians was  ___________________________

Brittle stars are the most active of the echinoderms, using their extensive and well-developed tube feet to chase and capture their prey.