Question

Which class of chordates existed first on earth?

Answer 1

Chordates:

1. Pikaia gracilens was one of the earliest chordates discovered to date.
2. Regarding its phylogenetic position, scientists are still unclear.
3. In fact, it is speculated to belong to a stem-chordate that is not closely related to any extant lineage.
4. Pikaia gracilens is the most primitive known vertebrate and therefore the ancestor of all descendant vertebrates, including humans.
5. The tiny creature had the beginnings of a backbone and skeletal muscle making it the oldest ancestor like us.