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NEET Syllabus Subject Wise 2025: Important Topics for Class 11 & 12

Population & Its Attributes MCQ - Practice Questions with Answers

Edited By admin | Updated on Sep 18, 2023 18:34 AM | #NEET

Quick Facts

  • Population & Its Attributes: Population Size or Density, Population Attributes - Age Pyramid, Population Attributes - Population Growth is considered one of the most asked concept.

  • 67 Questions around this concept.

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Population attribute having a ratio of male to female named:

It is much easier for a small animal to run uphill than for a large animal, because:

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

Population attribute is/are

A population has more young individuals compared to older individuals. What would be the status of the population after some years?

Pollen grains can be stored for several years in liquid nitrogen having a temperature of

Pollen tablets are available in tha market for:

Pollution refers to:

Order of different age group in the urn-shaped age pyramid for human population will be

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Natality refers to

Concepts Covered - 3

Population & Its Attributes: Population Size or Density
  • Individuals live in groups in a well defined geographical area, share or compete for similar resources, potentially interbreed and thus constitute a population.
  • The population that occupies a very small area, is smaller in size, such a population is called local population
  • A group of such a closely related local population is called meta-population.
  • A population has certain attributes that an individual organism does not. 

Population Size or Density:

  • It is the number of individuals of a species per unit area or volume.
  • It is usually expressed as the number of individuals per unit area or volume, for example, 100 trees per acre.
  • It is affected by the following factors:

1. Birth Rate or Natality:

  • Populations increase because of natality. 
  • Natality is equivalent to birth rate and is an expression of the production of new individuals in the population by birth, hatching, germination (or) fission.
  • For example, if in a pond, there are 20 lotus plants last year and through reproduction, 8 new plants are added, taking the current population to 28. Then, birth rate = 8/20 = 0.4 offspring per lotus per year.
     

 

2. Death Rate or Mortality:

  • It is the rate of loss of individuals (death rate) per unit time due to death or due to the different environmental changes, competition, predation, etc. 
  • For example, if individuals in a laboratory population of 40 fruit flies died during a specified time interval. Then, the death rate = 4/40 = 0.1 individuals per fruit fly per week.
     

3. Sex Ratio:

  • An individual is either a male or a female but a population has a sex ratio like 60% of the population are females and 40% are males.

 

Population Attributes - Age Pyramid
  • Population at any given time is composed of individuals of different ages. 
  • When the age distribution (percent individuals of a given age or age group) is plotted for the population, this is called age pyramid.
  • The age pyramid of human population generally shows the age distribution of males and females in a combined diagram.
  • The growth status of the population is reflected by the shape of the pyramids.

Expansive Pyramid: 

  • The population pyramid with broad base and with successive decline in the share of population of higher age groups is known as expansive pyramid.
  • This pyramid represents a situation of high fertility, high mortality, low life expectancy, higher population growth rates and low share of old age persons. 

Stationary or Stable Pyramid:

  • A pyramid is described stationary when the share of population remains constant in different age groups over the period of time. 
  • It represents a situation of low fertility, low mortality and high life expectancy. 
  • It indicates slow population growth or stable population. 
  • The stationary or near stationary population pyramid displays a somewhat equal share of juvenile and adult age groups.

Constrictive or Declining Pyramid:

  • A pyramid with a narrow base is called a constricted pyramid. 
  • It represents low fertility, low mortality, high life expectancy and ageing of population. 
  • It is typically associated with very advanced countries which have a high level of literacy, easy access to birth control measures and very good health and medical facilities.
     

 

Population Attributes - Population Growth
  • The size of a population for any species is not a static parameter, it keeps changing with time.
  • The density of a population in a given habitat during a given period, fluctuates due to the four basic processes:
    • Natality refers to the number of births during a given period in the population that are added to initial density.
    • Mortality is the number of deaths in the population during a given period.
    • Immigration is the number of individuals of the same species that have come into the habitat from elsewhere during the time period under consideration.
    • Emigration is the number of individuals of a population who left the habitat and moved elsewhere during a given period of time.
  • Out of these four, natality and immigration contribute an increase in population density while mortality and emigration contribute to the decrease in population density.
  • So, if N is the population density at time t, then its density at time t +1 is:

N_{t+1} = N_{t} + [(B + I) – (D + E)]- (D+E)]

Where, 
N = Population density
t = Time,
B = Birth rate,
I = Immigration,
D = Death rate,
E = Emigration

  • From the above equations, we can see that population density will increase if, (B + I) is more than (D + E).
     

 

Study it with Videos

Population & Its Attributes: Population Size or Density
Population Attributes - Age Pyramid
Population Attributes - Population Growth

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Books

Reference Books

Population & Its Attributes: Population Size or Density

Biology Textbook for Class XII

Page No. : 228

Line : 33

Population Attributes - Age Pyramid

Biology Textbook for Class XII

Page No. : 227

Line : 26

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