These jobs are geneticists and criminologists! Geneticists study genes and how they're inherited, seeing where the DNA came from. Criminologists will supply the samples to the geneticists, as they take them from the crime scene.
I think it may be conservation.
Autotroph is to producer as Hetrotroph is to consumer
Autotrophs make their own food, which makes them producers
While Hetrotrophs cannot make their own food, and must obtain it from another source, making them consumers
Any herbivores would have thrived if left alive. same with the smaller predators like foxes or owls. populations shoot up. increase in inbreeding if the islands are isolated and eventually disease catches up with them