Why is the sobriquet ‘The Evil Quartet’ used in the context of biodiversity? Name the members of this quartet. Why do we grieve for the genes when a species is lost?
The term ‘Evil Quartet’ is used to refer to the cause of the loss of biodiversity. The members of the quartet are: (i) Habitat loss and fragmentation: When due to various human activities, large habitats are broken up into smaller fragments the animals requiring large territories such as elephants, birds, etc. are getting affected badly and their populations decline. (ii) Over-exploitation: When the need for a resource becomes greed. e.g., overexploitation of passenger pigeons led to its extinction. Also marine fish are on the brink of being endangered due to overexploitation. (iii) Alien species invasion: Introduction of an intentional or unintentional species to a nearby area may disturb the harmony of existing species. e.g., Eichhornia after its introduction posed a big threat to the native species. (iv) Co-extinction: Extinction of one species invariably leads to the extinction of another when they are associated with each other in an obligatory way. E.g: When a host species becomes extinct, the obligate parasites that are dependent on it also die. We grieve for the genes when a species is lost because the wild forms are hardy and more resistant to pathogen attack and can be beneficial in crop breeding programs.
