Answer: it is involuntary, the process is called digestion.
Explanation:
bottleneck effect --- > A disease wipes out almost 90% of a population of birds, but the species adapts, and after 5 years its numbers increase dramatically.
gene flow ---> A population of rats travels on a cargo ship and mate with rats in a new region.
founder effect ---> Biologists introduce a small population of lizards on an island as part of a conservation effort.
mutation ---> A change in a DNA sequence causes a lizard to develop a darker skin color, which helps it hide from predators.