Question

Why is the Paleozoic era sometimes called the era of Trilobites? How many different species of trilobites existed during the Paleozoic? Why is the Holocene epoch (modern times) called the age of “Insects”? How many species of insects are in existence today?

Answer 1

Trilobite were first time appeared in Cambrian periods of Palaeozoic era at an age of about 540 Million years ago. These were the first invertibrate life in the ocean and ruled the ocean by approximately about 300 Million years successfully. During the late Devonian extinction about 30% of trilobite gone extinct along with 40% other oceanic life. There are most abundant specie of ocean all over the world. They have adopted the most unconditional environment to survive and pass much more boundaries of extinction. They have complex visual system, Sofisticated digestive system, the trilobite was the foundation life of the Arthropods. The rates of growth of trilobite in Ocean rise to 60 different taxonomic families in 40 Million years of there appearance. During Ordovician period the Ocean climate change rapidly due to cold climate and glaciation that causes rise in sea level and 50% of trilobite extinct in Ordovician Silurian extinction boundary. During Carboniferous period trilobite to face tremendous evolutionary pressure of others organisms of ocean like fish etc and got completely extinct at permian Triassic boundary or PT boundary which is the largest extinction events in the geological history of the earth called great dying. About 20000 different taxonomic species are developed during the palaeozoic Era and in accordance with this huge gorwth the Palaeozoic is called as Age of Trilobite.

It is interesting to know that the firstborn insect was about 480 Million years old during Ordovician period. Form that time to Holocene about 1.5 million species of insects has been recorded in fossil record. Starting from Ordovician period insects are able to pass the PT boundary and KT boundary as well and till they are existing in Earth.