A farmer used insecticide on his crops. This decreased the insect population by 97%, which protected his crops for the season. The abundant crops produced excess grain and seeds. There are two groups of birds in in the area. One has a sharp, thin beak that eats insects and the other has a thick, short beak that cracks seeds to eat.
What is the main selective pressure in this scenario?
insecticide
seeds
the crop health
insect population
The main selective pressure in this scenario is the insecticide, which decreased the insect population and may have affected the availability of food for the birds with thin, sharp beaks.
The main selective pressure in this scenario is the insecticide.
The main selective pressure in this scenario is the insecticide.
To understand why, let's break down the situation:
1. The farmer used insecticide on his crops to decrease the insect population by 97%. This means that a large majority of the insects, which are a food source for the birds, were eliminated.
2. As a result of the decreased insect population, the birds that rely on insects as their primary food source would face a shortage of their preferred food.
3. However, the crop that was protected by the insecticide produced an abundance of excess grain and seeds.
4. The birds have two different types of beaks - one group has a sharp, thin beak that is specialized for eating insects, while the other group has a thick, short beak that is specialized for cracking seeds.
Now, let's consider the selective pressure. In this scenario, the birds that have a sharp, thin beak that primarily eats insects would face challenges because the insect population has significantly decreased due to the insecticide. These birds may struggle to find enough food to survive and reproduce.
On the other hand, the birds with a thick, short beak that can crack seeds would benefit from the situation. The abundant crop with excess grain and seeds would provide an ample food source for them. They would have an advantage over the birds that rely on insects since their food supply would not be significantly affected by the insecticide.
Therefore, the main selective pressure in this scenario is the use of the insecticide, as it has a significant impact on the food availability for the birds with the sharp, thin beaks that eat insects.