Question

Tusklessness in African elephant populations is increasing because of heavy poaching by humans. Which graph demonstrates the type of natural selection occurring? (solid line is the original bell curve)

Answer 1

In the case of increasing tusklessness in African elephant populations due to poaching, the type of natural selection occurring is likely **directional selection**. This is because the selective pressure (the poaching of elephants with tusks) is favoring individuals without tusks, leading to a shift in the population over time.

To visualize this on a graph:

- The **original bell curve** (solid line) represents the original distribution of tusk size (with a range of individuals having varying sizes of tusks).
- After the selective pressure (poaching), the new distribution would shift to the left on the x-axis (tusk size), showing an increase in frequency for tuskless individuals (those with very small or no tusks).

In terms of what the graph would show:
- The solid line (original curve) would shift to form a new, modified curve that has a peak that is lower and to the left, representing an increased frequency of tuskless elephants.

This demonstrates that over time, the trait of having tusks is being selected against, leading to a change in the population's characteristics.