Commonly called the enterics due to the fact that they inhabit the intestinal tracts of humans and other animals.
Default network
When the brain is unoccupied, an fMRI indicates that blood continues to flow via a web of brain regions called the default network.
The default network is a web of brain regions that have activity that corresponds greatly with each other and different from other networks within the brain. The default network is active when an individual's attention is not concentrated on the external environment and it is measured with the functional magnetic resonance imaging technique (fMRI).
The smaller a population, the greater the potential effect of genetic drift on gene frequencies.
Genetic drift is an evolutionary term which refers to the random changes in a population's allele frequencies. These changes happen by chance due to the random selection of alleles from the genetic pool in each generation. Genetic drift can lead to either loss of some alleles or the fixation of others (100% frequency). The effect of genetic drift is stronger in smaller populations. This is because, the larger the population, the larger the sample size and the slower the result of genetic drift.