In a population of mice, individuals with medium brown fur are less likely to be seen by predators then light brown and dark brown mice. What type of selection is this, and what would the distribution curve for the mouse population look like?
A.disruptive; two peaks at either end of graph with a dip in the middle
B.stabilizing; two peaks at either end of graph with a dip in the middle
C.stabilizing; a tall, narrow peak in the center of the graph
D.disruptive; a tall, narrower peak in the center of the graph
C.stabilizing; a tall, narrow peak in the center of the graph.
This is because stabilizing selection favors average individuals and selects against extreme variations. In this case, medium brown mice are favored and have a higher chance of survival, leading to a concentration of individuals with medium brown fur in the population.
Paleontologists observed changes in sizes of black bears as their environment changed. During warmer periods between ice ages, most black bears were small. During ice ages, most black bears were large. Which type of selection is this, and how would a graph of the distribution curve of black bear size change as earth moved out of an ice age?
A.directional; the curve would shift to the right
B.directional; the curve would shift to the left
C.disruptive; the curve would break into two peaks with a dip in the middle
D.stabilizing; the curve would become taller in the middle and shorter on each side
A.directional; the curve would shift to the right.
This is because directional selection favors individuals with one extreme of a trait, in this case larger size during ice ages. As the environment changes and the earth moves out of an ice age, the selection pressure favors smaller individuals, causing the curve to shift to the right with a higher concentration of smaller black bears.
The correct answer is C. stabilizing; a tall, narrow peak in the center of the graph.
In this scenario, medium brown fur provides a selective advantage over both light brown and dark brown fur. This type of selection, where individuals with intermediate traits have a higher fitness than individuals with extreme traits, is known as stabilizing selection.
In a population undergoing stabilizing selection, the distribution curve would show a tall, narrow peak in the center of the graph. This indicates that the majority of individuals possess the trait that provides the highest fitness (medium brown fur, in this case), while individuals with extreme traits (light brown and dark brown fur) are gradually eliminated from the population.