Selection Types in Evolutionary Biology

The video tutorial explores natural selection through examples of ground finches, ducks, and lizards. It discusses how environmental changes affect the distribution of traits within populations, leading to directional, disruptive, and stabilizing selection. Ground finches in the Galapagos show variation in bill size, with deeper bills favored during droughts. Ducks experience disruptive selection, where extreme bill lengths are advantageous. Lizards undergo stabilizing selection, favoring average body sizes. The tutorial explains how these selection modes influence population traits over time.

What was the main factor that determined the survival of ground finches during the drought?

• The color of their feathers

• The size of their wings

• The depth of their bills

• The length of their legs

During the drought, which type of bill was less likely to survive?

• Medium-sized bills

• Narrow bills

• Deep bills

• Short bills

What environmental condition led to the change in bill size distribution among ground finches?

• New food sources

• Increased predators

• Drought

• Flooding

In directional selection, what happens to the mean trait value of a population over time?

• It becomes more variable

• It splits into two extremes

• It remains the same

• It shifts in one direction

What is a key feature of directional selection?

• The population splits into two groups

• The population becomes more diverse

• The mean trait value shifts over time

• The mean trait value remains constant

Which type of selection favors individuals with traits at both extremes?

• Artificial selection

• Disruptive selection

• Directional selection

• Stabilizing selection

In disruptive selection, what happens to the mean trait value?

• It becomes more variable

• It remains unchanged

• It decreases

• It increases

What is the outcome of stabilizing selection on a population?

• Decreased variability

• Emergence of new traits

• Shift in mean trait value

• Increased variability

Which selection type results in a more uniform population?

• Artificial selection

• Directional selection

• Stabilizing selection

• Disruptive selection

Which selection type is characterized by a decrease in the number of individuals with extreme traits?

• Stabilizing selection

• Directional selection

• Balancing selection

• Disruptive selection