3. Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics?
Species of a large population have a large number of genes, and therefore the number of different genes are high. A natural selection or genetic drift cannot lead to the extinction of the species. In small populations variation in genes is lesser. Here a slight disturbance in nature or accident may wipe out all the population and gene.
Currently, most tigers are confined only to Russia, Asia and Australia, and their number is decreasing drastically even after proclaiming them as endangered species. Loss of habitat due to urbanisation and deforestation are the major causes behind this.
Next: What factors could lead to the rise of a new species?
See also: Why are traits acquired during the lifetime of an individual not inherited?