Did a vertebrate come first or an invertebrate?

Answer 1

In vertebrates, definitely. The first animals which were invertebrates evolved in the Precambrian time around 600 million years ago. The first vertebrates appeared around 520 million years ago in the Cambrian. Dinosaurs did not emerge until about 230 million years ago in the Triassic.

Answer 2

Vertebrates evolved from invertebrates. Most likely a worm-like animal evolved a stiff rod like structure called notochord along its back and became something like the lancelet . Then later on the rod became a proper backbone, giving rise to real vertebrates in the form of fish.

Answer 3

Life started out with very simple organisms, and dinosaurs were very complex, so naturally they came long after the first life. Here's a way to appreciate the timing: If the whole existence of the Earth so far were represented as a single year, beginning January 1st, some life would be present before spring, but dinosaurs wouldn't appear until Christmas.