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A biologist studied the population of ra...

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

A

10

B

15

C

5

D

zero

Text Solution

Verified by Experts

The correct Answer is:
D
A population has birth rates and death rates. The rates are expressed as change in numbers (increase or decrease) with respect to members of the population.

In this case, the net increases in population will be zero. Because Birth rate (B)+Immigration (I)-Death rate(D)+Emmigration(I)=Density of population. Therefore, Density=[250+20]-[240+30]=0
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A biologist studied the population of rats in a barn. He found that the average natality was 250, average mortality 240, immigration 20 and emigration 30. The net increase in populations is :

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On investigation, the following data was obtained regarding population of rats in a barn: Average natality =500 per year, Average mortality = 480 per year, Immigration = 25 per year, Emigration = 45 per year Indicate whether the population is increasing or decreasing? If at the start of investigation there were 100 rats, how many would there be at the end of ten years?