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

Freshwater fish live in an environment where the surrounding medium contains salts and ions in much lower concentrations than their body fluids.  Consequently, freshwater fishes actively absorb salts and excrete large volumes of dilute urine

What is unusual about the lifecycle of nonparasitic lampreys?

The original form of the perforated pharynx was to act as a filter-feeding device. It then changed to pump water for what purpose?

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

The fishes, as we know them today, originated about 550 million years ago from a paraphyletic assemblage of jawed fishes that included the Ostrascoderms.

Hagfish have a number of odd characteristics including a low pressure circulatory system with four hearts. Write down two other unusual characteristics.

Which of the following is not a feature that chordates share with invertebrates

The fishes, as we know them today, originated about 550 million years ago from a paraphyletic assemblage of jawed fishes that included the Ostrascoderms.

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