A particular species of animals had three coat colors: White, yellow and black. A population of this species in Africa has more number of yellow animals and less number of white and black animals. After hundreds of years, the species evolved having very few yellow animals. The white and black animals were almost similar in quantity. The type of natural selection seen in this example is

Options

A. Stabilising selection
B. Directional selection
C. Disruptive selection
D. It could be both stabilising and disruptive selection

Answer

To solve the question regarding the type of natural selection observed in the described animal population, we can follow these steps:

### Step 1: Understand the Initial Population
The species has three coat colors: white, yellow, and black. Initially, the population in Africa has a higher number of yellow animals, with fewer white and black animals.

### Step 2: Observe Changes Over Time
After hundreds of years, the population shows a significant decrease in yellow animals, while the numbers of white and black animals become almost equal.

### Step 3: Identify the Type of Natural Selection
Given that the yellow animals (the intermediate phenotype) have decreased in frequency, while the extreme phenotypes (white and black) have increased, we need to determine the type of natural selection at play.

### Step 4: Analyze the Types of Natural Selection
1. **Stabilizing Selection**: This type favors the intermediate phenotype, which is not the case here since yellow animals are decreasing.
2. **Directional Selection**: This type favors one extreme phenotype over the other, which is also not applicable since both white and black are increasing.
3. **Disruptive Selection**: This type favors both extreme phenotypes while selecting against the intermediate phenotype. In this scenario, the white and black animals are thriving, while the yellow animals are declining.

### Step 5: Conclusion
Based on the observations and analysis, the type of natural selection occurring in this population is **disruptive selection**. This is characterized by the increase in frequency of the extreme phenotypes (white and black) at the expense of the intermediate phenotype (yellow).

### Final Answer
The type of natural selection seen in this example is **disruptive selection**.

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