A severe drought occurs in a large grassland, drastically reducing the available water sources. As a result, a population of cheetahs is reduced to only a small number of surviving individuals. Before the drought, the population had high genetic diversity, with variations in coat patterns and running speeds. After the drought, the remaining cheetahs are closely related and have much less genetic variation than before. Even as the population size begins to recover, the genetic diversity remains low.
Which evolutionary mechanism best explains the reduced genetic diversity in the cheetah population?
A) Bottleneck effect, because a drastic reduction in population size caused by the drought led to a loss of genetic variation.
B) Gene flow, because new cheetahs migrated into the population and changed the allele frequencies.
C) Directional selection, because the drought favored cheetahs with specific traits that helped them survive.
D) Mutation, because new genetic changes after the drought led to the loss of certain traits in the population.
Explanation: The bottleneck effect occurs when a population is drastically reduced due to an environmental event, leading to a sharp decline in genetic diversity. In this case, the drought randomly eliminated many cheetahs, leaving only a small group with a limited gene pool. Even after the population size increases again, the genetic diversity remains low because the surviving cheetahs only pass on the genes that were present in the reduced population.
Buffalo grass is a species of plant found on the grazing prairie of Wyoming. It is a tough grass that has silicates (compounds containing oxygen and silicon) that reinforce its leaves. This variation has allowed this type of grass to survive for many years in an adverse environment. This is an example of which mechanism of evolution?
Dark colored mice blend in with their environment better than light colored mice. Hawks catch and eat more light colored mice. The dark colored mice survive better and pass their genes onto the next generation.
The mechanism of evolution described: Dropdown 1
As a result genetic variation willDropdown 2.
The fastest cheetahs in a population are able to catch more food, reproduce and feed their offspring.
The mechanism of evolution described:
As a result genetic variation will.
Owls will usually eat more white mice over dark mice because they are easier to see at night. Because of this, the mice in most deciduous forests are usually darker than the mice found in the prairies. This is an example of which mechanism of evolution?
In 1789, the mutineers of a British ship set the captain and the crew adrift. Twenty seven adults and one baby arrived at an island called Pitcairn and their descendants lived on that island for decades. This event caused a drastic reduction in the population size which decreased the genetic variation in the population.
A small group of 15 wild rabbits becomes separated from the main population due to a flood. The isolated rabbits manage to establish a new population in a nearby forest. Over the years, the new rabbit population grows to 500 individuals. However, researchers observe that several traits, such as fur color and ear length, are significantly different from the original population, and these traits appear in higher frequencies than they did in the larger, original group.
Question:
What genetic phenomenon is responsible for the unusual traits found in the new rabbit population, and why do these traits appear more frequently than in the original population?
a) Gene flow, because the rabbits have mixed with other populations, leading to an influx of new traits. b) Genetic drift, because the small founding population's limited genetic pool led to random changes in allele frequencies. c) Natural selection, because certain traits were more beneficial in the new environment. d) Mutation, because new genetic variations appeared in the small population over time.
The correct answer would be b) Genetic drift, since the isolated founding group had a limited genetic pool, which led to random changes in allele frequencies, possibly amplifying certain traits that may have been rare in the original population.