Question

A biologist studied the population of rats in a barn. He found that average natality was 250, average mortality 240, immigration 20 and emigration 30. The net increase in population is

• A. Zero
• B. 10
• C. 15
• D. 5

Answer 1

The Correct Option is A

To solve this problem, we need to calculate the net increase in the population of rats in the barn. This can be determined by considering the following factors:

1. Average Natality (Birth Rate): This is the number of new individuals entering the population due to birth. Here, the natality is given as 250.
2. Average Mortality (Death Rate): This is the number of individuals leaving the population due to death. Here, the mortality is given as 240.
3. Immigration: This is the number of individuals entering the population from outside. Here, immigration contributes an additional 20 individuals.
4. Emigration: This is the number of individuals leaving the population to move elsewhere. Here, emigration removes 30 individuals from the population.

We can calculate the net change in population using the formula:

\text{Net Increase} = (\text{Natality} + \text{Immigration}) - (\text{Mortality} + \text{Emigration})

Plugging in the values:

\text{Net Increase} = (250 + 20) - (240 + 30)

Simplifying further:

\text{Net Increase} = 270 - 270 = 0

Thus, the net increase in the population of rats is Zero.

Therefore, the correct answer is: Zero.