Question

In which period of the paleozoic era first vertebrates appear.
A. Ordovician
B. Devonian
C. Silurian
D. Mississipian

Answer 1

Hint: The Paleozoic Era, which ran from about 542 million years ago to 251 million years ago, was a time of great change on Earth. The era began with the breakup of one supercontinent and the formation of another.

Complete Answer:
- This development occurred against the background of moving landmasses and an evolving atmosphere. During the Cambrian Period of the Paleozoic, the continent went through a change. They had been joined as one supercontinent, Rodinia, however during the Cambrian Period, Rodinia divided into Gondwana (comprising of what might in the long run become the advanced continent of the Southern Hemisphere) and littler landmasses comprised of pieces and bits of the land that would in the end make up the present northern continent.

- The Cambrian was warm around the world, yet would be trailed by an ice age in the Ordovician, which made ice sheets structure, sending ocean levels descending. Gondwana moved further south during the Ordovician, while the latter continent began to draw nearer together. In the Silurian Period, the land masses that would turn out to be North America, focal and northern Europe, and western Europe drew even nearer together. Ocean levels rose once more, making shallow inland oceans.

- In the Devonian, the northern land masses kept combining, and they at long last consolidated into the supercontinent Euramerica. Gondwana still existed, yet the remainder of the planet was sea. By the last time of the Paleozoic, the Permian, Euramerica and Gondwana got one, shaping maybe the most popular supercontinent of all: Pangaea. The monster sea encompassing Pangaea was called Panthalassa. Pangaea's inside was likely dry, since its monstrous size forestalled water-bearing precipitation mists from infiltrating a long way past the coasts.

Hence the Correct Option: - A) Ordovician.

Note: The significant divisions of the Paleozoic Era, from most established to most youthful, are the Cambrian (541 million to 485.4 million years prior), Ordovician (485.4 million to 443.8 million years back), Silurian (443.8 million to 419.2 million years prior), Devonian (419.2 million to 358.9 million years prior), Carboniferous (358.9 million to 298.9 million years back), and Permian (298.9 million to 252.2 million years back) periods. The Paleozoic takes its name from the Greek word for antiquated life.