GEOLOGY

Detailed explanation-1: -Trilobites were some of the first multicellular animals to live in the world’s oceans. Their fossil record extends back 530 million years to the early part of the Cambrian Period and indicates that trilobites evolved rapidly in the shallow seas of this time.

Detailed explanation-2: -The oldest trilobite body fossils around the world, at or near the Terreneuvian–Cambrian Series 2 boundary (ca. 521 Ma), already show established diversity, phylogenetic disparity, and biogeographic provincialism (11–13).

Detailed explanation-3: -What about some of the oldest animals in our collections? Just a few steps from the stromatolites, you can find trilobites, which are among the oldest animals on Earth. These critters evolved during the Cambrian Period, starting around 500 million years ago.

Detailed explanation-4: -The animal. Like many invertebrate animals living today, including crustaceans, spiders and insects, trilobites were arthropods, belonging to the phylum Arthropoda. Geologists know that they were marine animals because of the rocks in which they are found and the other types of fossils associated with them.