Which of the following situations will lead to natural selection?

• A. A population of insects is exposed to a pesticide, and all individuals are equally affected.
• B. A population of birds develops a mutation that allows them to digest a new type of seed, increasing their survival rate.
• C. A population of mammals migrates to a new area where food is abundant, and all individuals thrive equally.
• D. A population of fish experiences a sudden drop in water temperature, but all individuals survive equally well.

Answer: (B)

Verified step by step guidance

1. Understand the concept of natural selection: Natural selection is a process where individuals with certain heritable traits tend to survive and reproduce at higher rates than others because of those traits.
2. Identify the key factor for natural selection: Variation in traits among individuals in a population is crucial for natural selection to occur. Without variation, all individuals are equally affected by environmental changes, and no selection can take place.
3. Analyze each situation: Look for scenarios where there is variation in traits that affect survival or reproduction. This variation can be due to mutations, environmental changes, or other factors.
4. Evaluate the given situations: In the situation where a population of birds develops a mutation allowing them to digest a new type of seed, there is a variation in traits (the mutation) that increases survival rate, leading to natural selection.
5. Conclude which situation leads to natural selection: The situation with the birds and the mutation is the one that leads to natural selection because it involves a heritable trait that affects survival and reproduction, unlike the other scenarios where all individuals are equally affected.