Populations can have variety, despite being made up of the same species. If a population has different expressed traits, this can be due to different inherited alleles. The frogs below are the same species, but they have different shades of green based on their inherited alleles. In a particular environment, lighter green frogs are easier to see by predators. Explain how natural selection could lead to a change in allele frequency.

Answer / Explanation:

If an animal is more visible to predators, it is more likely to be caught and killed than an animal that is more hidden.

Therefore, in this case, light green frogs will be caught by predators more often. This reduces their likelihood of surviving to reproductive age and being able to pass their genes on to their offspring.

In contrast, frogs that are dark green will be more able to avoid predators, increasing their chance of being able to pass their genes on to offspring.

Therefore, if there are more green frogs reproducing and passing their information on to the next generation, then there will be an increased frequency of the alleles responsible for producing a dark green colour, whereas the alleles for the light green colour will reduce in frequency. This how the process of natural selection occurs.