Question

Which of the following is not a living fossil -
(a) King crab
(b) Sphenodon
(c) Archaeopteryx
(d) Peripatus

Answer 1

Fossils are the preserved remains or traces of ancient organisms. They are in the form of rock. They are helpful in providing the knowledge of the ancestors and the phylogenetic relationships of the organisms.

Complete answer:
The living fossils are those organisms that are living and even in hundreds of years, they remain unchanged even in the unfavorable environmental conditions. Archaeopteryx is not a living fossil in fact it is a connecting link between the birds and the reptiles while King crab, Sphenodon, and Peripatus are the living fossils. Archaeopteryx is basically known to be the connecting link between birds and reptiles as it looks like a bird and possesses bird wings. The teeth and the tail are closer to those of reptiles. As we know that birds evolved from reptiles, therefore Archaeopteryx links reptiles and birds.

Additional information:
Importance of fossil are as follows:
-Fossils present at the bottom of the rock are simple while the ones which are present at the top are the most recent fossils. This succession revolves around evolution.
-They act as the direct link and connect two links two groups together.
-The fossils of the dinosaurs were found beneath the rock as they live under the rocks to get warmth for their body. This also referred to the evolution where it was indicated that the dinosaurs developed wings like birds for the purpose of flying. Hence, it helps in showing the evolutionary or phylogenetic relationship between the birds and the reptiles.
-By studying the geological time scale, the records of the fossils of various mammals can be overlooked to study the series of evolution.

Note:
King crab are the living fossils that were found over 400 million years ago having a hard shell and belong to the phylum Arthropoda. Sphenodon is the living fossil found around 200 million years ago having a wedge-like tooth. Peripatus are the worms that are living fossils and are found around 570 million years ago.