Invasion of an Alien species leads to extinction of native species. Justify this with two examples.

Explanation

When alien species are introduced into a habitat, they turn invasive and establish themselves at the cost of the native species.
Ex : Nail perch introduced into lake Victoria, in east Africa led to the extinction of 200 specie of Ciohlid fish in tha lake. Illegal introduction of exotic African catfish for aquaculture purposes in posing a threat to the native catfish.