Natural selection
Greater than 2 cm or less than 2 cm
A scientist measures the circumference of acorns in a population of oak trees and discovers that the most common circumference is 2 cm. What would you expect the most common circumference(s) to be after 10 generations of *directional* selection? -2 cm -Greater than 2 cm or less than 2 cm -Greater than 2 cm and less than 2 cm -Can't tell from the information given
Greater than 2 cm and less than 2 cm
A scientist measures the circumference of acorns in a population of oak trees and discovers that the most common circumference is 2 cm. What would you expect the most common circumference(s) to be after 10 generations of *disruptive* selection? -2 cm -Greater than 2 cm or less than 2 cm -Greater than 2 cm and less than 2 cm -Can't tell from the information given
2 cm
A scientist measures the circumference of acorns in a population of oak trees and discovers that the most common circumference is 2 cm. What would you expect the most common circumference(s) to be after 10 generations of *stabilizing* selection? -2 cm -Greater than 2 cm or less than 2 cm -Greater than 2 cm and less than 2 cm -Can't tell from the information given
Disruptive selection
Imagine a plant of extremely variable height that is pollinated by 3 different pollinators, one that was attracted to short plants, another that preferred plants of medium height and a third that visited only the tallest plants. If the pollinator that proffered plants of medium height disappeared from an area, what type of selection would it be?
Stabilizing selection
Imagine a plant that is too short, and it may not be able to compete with other plants for sunlight. However, tall plants may be more susceptible to wind damage. The medium plants will increase. What type of selection is this scenario?
Stabilizing selection
Starlings produce an average of five eggs in each clutch. If there are more than five, the parents cannot adequately feed the young. If there are fewer than five, predators may destroy the entire clutch. What type of selection is this?
Disruptive selection
The occurrence of large or small beak sizes among seed crackers in the absence of medium sized beaks is what type of selection?
Directional selection
There was a selection pressure against short necks, since individuals with short necks could not reach as many leaves on which to feed. As a result, the distribution of neck length favored individuals with long necks. Using the example of giraffe necks, what type of selection would this scenario be?
Extremes of a trait
What types of individuals in a population are represented by the two ends of a bell curve?
Disruptive selection
When individuals at both of the extremes of a trait are both more fit and are favored over the average individuals in the population
Directional selection
When individuals at one end of the curve have higher fitness and are favored more than individuals in the middle or at the other end
Stablizing selection
When the average individuals in the population have higher fitness and are favored
