Question

Age of amphibians is__________.
a. Carboniferous
b. Ordovician
c. Devonian
d. Cambrian

Answer 1

Hint: By careful analysis of the distribution of fossils in different strata of rocks, the time in history when different species were formed or become extinct can be inferred. Scientists have divided the earth’s past into large blocks of times called eras. Eras are further subdivided into smaller blocks of time called periods and some periods are subdivided into epochs. Carboniferous, Ordovician, Devonian, and Cambrian are periods belonging to the Paleozoic era.

Complete answer:
There are four eras- Precambrian/Proterozoic, Paleozoic, Mesozoic (age of reptiles), and Cenozoic (age of mammals). Each ear is divided into periods.

Now, let us consider all the options.
> Carboniferous: Extensive forest of vascular plants; first seeds plants were found in this period. The fossils found in this period underline that this period was the origin of reptiles. Amphibians dominate this period, thus it is referred to as the Age of amphibians.

> Ordovician: This period was around 500-505 million years ago. In this period, the first vertebrates, especially jawless fishes, were found. Marine algae were abundant. It is known as the Age of invertebrates.

> Devonian: It was around 408-400 million years ago. In this period a diversification of bony fishes was seen through fossil evidence. It is referred to as the Age of Fishes.

> Cambrian: It was around 550-544 million years ago. This period fossil suggests that most of the invertebrates originated from here. In this period there was the diversification of phylum algae.

Hence, the correct answer is option (A).

Note: Fossils are formed when parts of dead organisms decay with time and get replaced, molecule by molecule, by inorganic material like iron pyrites, silica, and calcium carbonate. This mineral replacement is called petrification.