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प्रश्न
The following diagrams are the age pyramids of different populations. Comment on the status of these populations.
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उत्तर
Fig.A: It is a ‘pyramid’ shaped age pyramid. In this figure, the base i.e pre- reproductive stage is very large when compared with the reproductive and past reproductive stages of the population. This type of age structure indicates that the population would increase rapidly.
Fig.B: It is an ‘inverted bell’ shaped pyramid. In this figure, the pre-reproductive and reproductive stages are the same. This type of age structure indicates that the population is stable.
Fig.C: It is ‘Urn’ shaped pyramid. In this figure, the pre-reproductive and reproductive stages are less than the post-reproductive stage of this population. In this population more older people are present. This type of age structure indicates that the population definitely is declining.
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संबंधित प्रश्न
(a) Name the two growth models that represent population growth and draw the respective growth curves they represent.
(b) State the basics for the difference in the shape of these curves
(c) Which one of the curves represents the human population growth at present? Do you think such a curve is sustainable? Give reason in support of your answer.
Study the graph given below and answer the questions that follow :
(i) Write the status of food and space in the curves (a) and (b).
(ii) In the absence of predators, which one of the two curves would appropriately depict the prey population?
(iii) Time has been shown on X-axis and there is a parallel dotted line above it. Give the significance of this dotted line
What is an age-pyramid?
What is reproductive fitness? Explain it with the help of an example.
Study the flow chart given below and complete the equation that follows by identifying 1, 2, 3 and 4.
Nt + 1 = Nt + {(1+ 2) − (3 + 4)}
Animals that can move from fresh water to sea called as ________.
Measures of ‘Central tendency’ refer to:
Nutrient enrichment of water body result.
Population having large number of postreproductive and small number of prereproductive age group is called
`"dN"/"dt" = "rN" (("K"- "N")/"K")` in logistic growth "K" represents:
What parameters are used for tiger census in our country’s national parks and sanctuaries?
The density of a population in a habitat per unit area is measured in different units. Write the unit of measurement against the following:
Bacteria
Label the three tiers 1, 2, 3 given in the above age pyramid.
Given below is the Age Pyramid of the population in one of the states in India as per 2011 census. It depicts the male population on the left-hand side, female population on the right-hand side, newborns towards the base and gradually increasing age groups as we move from base to the top, with the oldest population at the top. Study this pyramid and comment upon the appropriateness of the Assertion and the Reason.
Percentage to the total population
Assertion: It is a stable population.
Reason: The pre-reproductive and reproductive individuals are almost in equal numbers and the post-reproductive individuals are relatively fewer.
Important attributes belonging to a population but not to an individual are:
- Birth rate and death rate
- Male and female
- Birth and death
- Sex-ratio
Select the correct option from the given options:
The number of lily plants in a pond was found to be 50. After one year, the number. increased to 65. Calculate the natality of lily plants.
