Practicing Success

Target Exam

CUET

Subject

Biology

Chapter

Organisms and Populations

Question:

Read the given passage and answer the following questions :

In nature, we rarely find isolated, single individuals of any species; majority of them live in groups in a well defined geographical area, share or compete for similar resources, potentially interbreed and thus constitute a population. A population has certain attributes whereas, an individual organism does not. An individual may have births and deaths, but a population has birth rates and death rates. In a population these rates refer to per capita births and deaths. The rates, hence, expressed are change in numbers (increase or decrease) with respect to members of the population. Here is an example. 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. Another attribute characteristic of a population is sex ratio. An individual is either a male or a female but a population has a sex ratio (e.g., 60 per cent of the population are females and 40 per cent males). A population at any given time is composed of individuals of different ages. If the age distribution (per cent individuals of a given age or age group) is plotted for the population, the resulting structure is called an age pyramid. For human population, the age pyramids generally show age distribution of males and females in a diagram. The shape of the pyramids reflects the growth status of the population - (a) whether it is growing, (b) stable or (c) declining.

What does the sex ratio of a population refer to?

Options:

The total number of males

The total number of females

The proportion of males and females in the population

The reproductive capacity of individuals

Correct Answer:

The proportion of males and females in the population

Explanation:

The correct answer is Option (3) – The proportion of males and females in the population

The sex ratio of a population refers to the relative number of males and females within that population. It is typically expressed as the proportion or ratio of males to females. This ratio is an important demographic parameter because it affects the reproductive potential and dynamics of the population.

Understanding the sex ratio is crucial for studying population dynamics, mating patterns, and predicting future population growth or decline.