Allopatric speciation is just a fancy name for speciation by geographic isolation, discussed earlier. In this mode of speciation, something extrinsic to the organisms prevents two or more groups from mating with each other regularly, eventually causing that lineage to speciate.
The downside of this is that it can only tell if youâve engaged in drug use in that window. For example, if you smoke marijuana on a daily basis but stop 2-3 days prior to your mouth swab test, the results will probably come back negative. It canât detect prolonged use or the remaining presence of a trace amounts like a urine test can.
Marijuana does not stay in saliva for very long. Most of the rules that apply to marijuanaâs detection time in urine and hair do not apply to marijuana in saliva. It can be detected by a saliva drug screen about an hour after intake. The accuracy of a saliva drug test (97%-98%) will decrease rapidly about 12 hours after the marijuana was consumed.