The best evidence of such phenomena could be a population's genetic variation decrease.
When a population bottleneck occur it means that for some reason (i.e. environmental events) the size of a population is largely reduced. This leads to reduction of the genetic variation in that new smaller population. When a bottleneck occur, the founder effect is normally seen, which is that one population is established by a small group of a previously larger population leading once again the genetic variation, now though with a bigger population, to be very reduced.
A group of tissue that work together is a organ
It's the definition of a SPECIES.
Those animals are from the same species.
False negative is a condition when you got a negative result for a specimen which was positive. To prevent false negative occur, first you need to use golden standard test or a test with high specificity. You can do multiple tests to ensure the specimen is negative and using a positive control to make sure the reagent is still working fine.
