Beetles on a diet Imagine a year or two of drought in which there are few plants a beetle can eat.
First generation of starving beetles
All the beetles have the same chances of survival and reproduction, but because of food restrictions, the beetles in the population are a little smaller than the preceding generation of beetles.
Second generation of starving beetles

Beetles of a different color

Most of the beetles in the population (say 90%) have the genes for bright green coloration and a few of them (10%) have a gene that makes them more brown.

Second generation of starving beetles

Some number of generations later, things have changed: brown beetles are more common than they used to be and make up 70% of the population.

Second Generation

Image credits: University of California Museum of Paleontology's Understanding Evolution (http://evolution. berkeley. edu).

Question: Which example illustrates descent with modification — a change in gene frequency over time, "Beetles on a diet" or "Beetles of a different color"? Why did you choose this example?