A tracheotomy is performed if enough air is not getting to the lungs, if the person cannot breathe without help, or is having problems with mucus and other secretions getting into the windpipe because of difficulty swallowing. There are many reasons why air cannot get to the lungs.
Trending Now. Answers. Best Answer: Yes, the smallest unit of evolution is the population. The reason is, the techical definition of evolution is change in allele frequency. You have to have a population in order to run the statistics to measure if there has been a change. Remember, a population does not necessarily mean all animals of one species.
The idea that evolution = natural selection is the biggest bugaboo of them all. It does not. Adaptive change is one kind of change, but probably a minority of the overall change that occurs at the genetic level (but maybe not at the phenotypic level).peciation is important and it is a kind of evolutionary event, but if you want to talk about the rate of speciation, then call it the ârate of speciationâ not the ârate of evolution.â They are not the same thing. Not addressed in this model is the simple fact that speciation does NOT take millions of years.