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Three Modes of Natural Selection

 

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Directional Selection

 

  1. What is the most common bill size in the Galapagos Ground Finch?

 

 

  1. What food source was available after the drought of 1977?

 

 

  1. What bill size was selected for by the drought of 1977?

 

 

  1. What bill size was selected against by the drought of 1977?

 

 

  1. Why was this bill size selected against?

 

 

  1. Which of the three histograms from the right column demonstrates what will happen to the population if these environmental conditions were to continue for several years? (Draw the histogram)

 

 

 

  1. What type of selection does this represent?

 

 

  1. What is the result of this type of selection?

 

 

  1. What is the key feature of directional selection?

 

Disruptive Selection

 

  1. What is the most common bill length in the ducks?

 

 

  1. What two bill lengths were selected for

 

 

  1. Why was each different bill length selected for?

 

 

  1. What bill length was selected against?

 

 

 

  1. Why was this bill length selected against?

 

 

  1. Which of the three histograms from the right column demonstrates what will happen to the population if these environmental conditions were to continue for several years? (Draw the histogram)

 

 

 

 

  1. What type of selection does this represent?

 

 

 

  1. What is the result of this type of selection?

 

 

 

  1. What does disruptive selection favor?

 

 

 

Stabilizing Selection

 

  1. What is the most common size for green lizards?

 

 

 

  1. What size of lizard was selected for

 

 

  1. What two sizes of lizards was selected against?

 

 

  1. Why was each lizard size selected against?

 

 

 

  1. Which of the three histograms from the right column demonstrates what will happen to the population if these environmental conditions were to continue for several years? (Draw the histogram)

 

 

  1. What type of selection does this represent?

 

 

 

  1. What is the result of this type of selection?

 

 

 

  1. What does stabilizing selection favor?

 

 

 

  1. Describe the population as a result of stabilizing selection.

 

 

Take the quiz at and write your answers below:

https://www.qzzr.com/c/quiz/180737/3f0b4f31-6876-42a5-b2dc-2e5fbac6b1eb

 

  1. Small lizards have difficulty defending territories, but large lizards are more likely to be preyed upon by owls.  Which mode of natural selection does this describe?

 

 

  1. In a species of snail, dark snails are better hidden from birds in the shady forest and lighter snails are better hidden in the well lit areas. Which mode of natural selection does this describe?

 

 

  1. Competition between two races within a species over time might lead to two different species through ...

 

 

  1. Directional selection...

 

 

 

 

  1. Robins typically lay four eggs. Larger clutches may result in malnourished chicks and smaller clutches may result in no viable offspring. Which mode of natural selection does this describe?

 

 

  1. In a population of woolybeasts, individuals with long snouts tend to survive better on an island that has burrowing termites. Which mode of natural selection does this describe?

 

 

  1. In a certain population, disruptive selection is occurring. In this population, which is most likely to survive?

 

 

 

  1. The fact that the majority of human newborns weigh around 7 pounds is reflective of ...

 

  1. The occurrence of large or small beak sizes among seed crackers in the absence of medium-sized beaks is an example of ... 

 

 

  1. Female elk tend to choose males that have large body size and large antlers with many points.  Which mode of natural selection does this describe?