PASSAGE
The biological wealth of our planet has been declining rapidly and the accusing finger is clearly pointing to human activities. The colonisation of tropical pacific islands by humans is said to have led to extinction of more than 2000 species of native birds. The IUCN red list documents the extinction of 784 species. Since the origin and diversification of life on earth, there were five episodes of mass extinction of species. Current species extinction rate as estimated to be 100-1000 times faster. There are four major causes called “The Evil quartet” Habitat loss, over exploitation, Alien species invasion and co-extinction. Conservation efforts are necessary to preserve biodiversity and protect endangered species and their habitats.
Mr. X wants to understand the ‘Evil Quartet’ to know the reasons of Biodiversity loss. It is :
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Habitat loss, over exploitation, Alien species invasions and co-extinctions
The ‘Evil Quartet’ is the name given to the four major causes of the loss of biodiversity, as the passage lists.
Option (1) Habitat loss and fragmentation only — Incorrect. Habitat loss is the most important cause, but it is only one of the four.
Option (2) Over exploitation and Alien species invasions only — Incorrect. This names two of the four causes. Over-exploitation is over-harvesting, when ‘need’ turns to ‘greed’, and alien species can turn invasive and wipe out native species. Both are real causes, but the option leaves out habitat loss and co-extinctions.
Option (3) Co-extinctions and Alien-species invasion — Incorrect. Again, only two of the four causes. In co-extinction, species tied to another in an obligatory way die out with it, as parasites with their host fish. These two are real causes, but the option leaves out habitat loss and over-exploitation.
Option (4) Habitat loss, over exploitation, Alien species invasions and co-extinctions — Correct. The four major causes of biodiversity loss, called ‘The Evil Quartet’, are habitat loss and fragmentation, over-exploitation, alien species invasions and co-extinctions. Only an option with all four names the quartet.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.