Question

Pikaia gracilens, the earliest known chordate collected from the Burgess Shale of British Columbia, closely resembles:

a. Hagfish
b. Lamprey
c. Lancelet
d. Tunicate

Answer 1

Pikaia gracilens, the earliest known chordate, closely resembles lampreys (option b).

Step-by-step explanation:

Pikaia gracilens is an extinct species of animal that lived during the Cambrian period, approximately 540 million years ago. It was discovered in the Burgess Shale of British Columbia, Canada, and is considered one of the most primitive chordates known to date. Chordates are a group of animals that include vertebrates such as humans, as well as other animals with a notochord, a hollow nerve cord, and gill slits.

Lampreys (option b) are a type of fish that belong to the phylum Chordata, and are closely related to hagfishes (option a) and vertebrates. They have a notochord, a hollow nerve cord, and gill slits, which are similar to the characteristics of Pikaia gracilens. In fact, lampreys are sometimes referred to as “living fossils” because they have remained relatively unchanged for millions of years, and their anatomy is similar to that of their ancient ancestors.

So, the correct answer is B.