Question

Which is the correct order of increasing geological time scale for a hypothetical vertebrate evolution?
A. Cenozoic, Mesozoic, Palaeozoic. Proterozoic
B. Cenozoic, Palaeozoic. Mesozoic. Proterozoic
C. Proterozoic, Cenozoic. Palaeozoic, Mesozoic
D. Proterozoic, Palaeozoic, Mesozoic, Cenozoic

Answer 1

Hint: The above mentioned time scales are different geological eras. According to the macroscopic fossil record, the Palaeozoic, Mesozoic, and Cenozoic eras represent "old life," "middle life" and "recent life" respectively.

Complete answer: A ‘Geological Time Scale’ or ‘GTS’ is used to define the timing and relationships of events in geological history by geologists, palaeontologists, and other earth scientists. An era refers to a particular geologic time subdivision that divides an ‘eon’ into smaller units of time. The sequence of the geological time scale is as follows:
a) The first organism occurred in the Proterozoic era.
b) The age of fish and amphibians is the Palaeozoic era.
c) The Age of Reptiles is the Mesozoic era. It is also known as the age of dinosaurs.
d) The Cenozoic era is referred to as the age of mammals.
Proterozoic era covers the period from the emergence of oxygen in the atmosphere to just before the emergence of complex life on the Earth. The Palaeozoic era started with the breakup of one supercontinent and the formation of another and during this time plants have become prevalent; the land was colonized by the first vertebrate species.
Hence, the correct answer is option D.

Note: A method of chronological dating that classifies geological strata in time is the geologic time scale (GTS). The primary and largest catalogued divisions of time are periods called eons. The first eon was the Hadean when the Earth and moon were predicted to be formed, lasting over 600 million years.