Evolution Test - 4

Poison glands of snakes are homologous to salivary glands of vertebrates.They are modification of the parotid salivary gland.

Organs with anatomical similarities but performing different functions are called homologous organs.

Vestigeal organs are functionless and smaller in size.Vestigiality refers to genetically determined structures or attributes that have apparently lost most or all of their ancestral function in a given species, but have been retained through evolution.

Among the given options, diaphragm is not a vestigial organ.The diaphragm separates the thoracic cavity containing the heart and lungs, from the abdominal cavity and performs an important function in respiration: as the diaphragm contracts, the volume of the thoracic cavity increases and air is drawn into the lungs.

The presence of salts in animal body fluid gives the proof that the life originated in sea water.

Coacervates were the first to be formed during origin of life.They are microscopic spontaneously formed spherical aggregates of lipid molecules that are held together by electrostatic forces and that may have been precursors of cells.

Balanoglossus is a connecting link between chordates and non-chordates. It has notochord in the upper part of the body and has no nerve chord.

Limulus is a living fossil.A living fossil is a living species (or clade) of organism that appears to be similar to a species otherwise known only from fossils, typically with no close living relatives.

Sudden appearance of an ancestral character is called atavism. An atavism is an evolutionary throwback, such as traits reappearing which had disappeared generations before.

Among these, peripatus is a living fossil.Peripatus is an invertebrate, said to be a living fossil because the living members appear similar to fossil species as much as 570 million years old, and because the group is transitional between the Arthropoda (including crustaceans and insects) and primitive Ecdysozoa such as tardigrades, priapulids and nematodes.