environmental stochasticity, and demographic stochasticity.
Explanation:
The small population species are prone to extinction. Due to the process of evolution, many species raised from a single species. This is because of variation, different individuals came and survive. But all the species can't achieve reproductive success. They also can't adapt to the changing environment. The changing of the environment in the biodiversity is called stochasticity. The fewer Populus species can't face the natural selection. As a result, their mortality rate is more and the natality rate is high. Sometimes demographic stochasticity also responsible. The fewer reproduction results in less number of the individual over time. This causes mass extinction. The extinction of dinosaurs is an example of mass extinction. The more reproduction of the species means more variety. They can better adapt to the changing environment. Some of the extinct animals are also living and known as living fossils. e.g. Armadillo, Platypus. The changing biodiversity and randomness of the population cause the extinction of a small population.
Answer: The most serious of these mutations will be the insertion of 2 bases. Becasue the genetic code is read in triplets, a 2 base insetion will alter the reading frame of the code causing a frameshift mutation meaning every amino acid after the site of the mutation will be incorrect.