B. Sympatric evolution. is responsible to this. It's the process of evolving species from one shared ancestor in the same geographic region.
Complete question:
In the 1890s, Northern elephant seals were hunted almost to extinction. An unknown population of less than one hundred animals managed to survive on the tiny island of Guadalupe off of Mexico. The current population of over 100,000 is thought to be derived from that tiny remnant population. Compared to the Southern elephant seals (which did not experience such a bottleneck), the Northern elephant seals likely have -------- (Lower - Higher) genetic diversity and -------- (Lower - Higher) levels of genetic diseases.
Answer:
In the 1890s, Northern elephant seals were hunted almost to extinction. An unknown population of less than one hundred animals managed to survive on the tiny island of Guadalupe off of Mexico. The current population of over 100,000 is thought to be derived from that tiny remnant population. Compared to the Southern elephant seals (which did not experience such a bottleneck), the Northern elephant seals likely have Lower genetic diversity and Higher levels of genetic diseases.
Explanation:
Genetic drift is the random change that occurs in the allelic frequency of a population through generations. The magnitude of this change is inversely related to the size of the original population. These changes produced by genetic drift accumulate in time. Eventually, some alleles get lost, while some others might set. Genetic drift affects a population and reduces its size dramatically due to a disaster or pressure-bottleneck effect- or because of a population split -founder effect-.
In the exposed example, extensive hunting acted as a pressure that reduced the number of Northern elephant seals to fewer than 100. This population experienced one or many generations of small size since these animals were affected by hunting. As the survivors did not have the whole genetic pool of the original population, the population size might have recovered to a current population size of 1000,000 individuals, but <u>the genetic pool might have not</u>. When the small population increases in size, it will have a genetically different composition from the original one. In these situations, there is a<u> reduced genetic variability</u>, with a possibility of developing a peculiar allelic component. If the survivors in the population carried or developed a mutation, probably this mutation passed from generation to generation. It will involve more individuals each time and<u> increase the probability of developing a genetic disease</u>.
Protists are essential in food chains, especially in marine environments.They are also leaders in global carbon fixation. Another role they have is decomposing organisms.
