If 100 fruit flies die in a laboratory population of 1,000 during a month, the death rate in the population is ________ individual per fruit fly per month:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 0.1
Death rate = number dying ÷ population = 100 ÷ 1000 = 0.1 individual per fruit fly per month.
Option (1) 0.1 — Correct. Death rate is the number of deaths per individual over a period. Here 100 of 1000 flies die in a month, so the death rate = 100 ÷ 1000 = 0.1 individual per fruit fly per month.
NCERT Extract:
Population Attributes – “… If in a pond there were 20 lotus plants last year and through reproduction 8 new plants are added, taking the current population to 28, we calculate the birth rate as 8/20 = 0.4 offspring per lotus per year. If 4 individuals in a laboratory population of 40 fruitflies died during a specified time interval, say a week, the death rate in the population during that period is 4/40 = 0.1 individuals per fruitfly per week.”