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प्रश्न
An individual and a population has certain characteristics. Name these attributes with definitions.
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उत्तर
A population has certain attributes that 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, respectively. The rates, hence, expressed as change in numbers (increase or decrease) with respect to members of the population.
- 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 the human population, the age pyramids generally show the age distribution of males and females in a combined diagram. The shape of the pyramids reflects the growth status of the population.
- Whether it is growing
- Stable
- Declining

Representation of age pyramids for human population
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संबंधित प्रश्न
Construct an age pyramid which reflects a stable growth status of human population.
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
Represent diagrammatically three kinds of age-pyramids for human populations.
If a population growing exponentially double in size in 3 years, what is the intrinsic rate of increase (r) of the population?
What is an age-pyramid?
What is reproductive fitness? Explain it with the help of an example.
Answer the following question.
What is "population" according to you as a biology student?
Mention the different ways by which the population density of different species can be measured.
The phenomenal and rapid increase of population in a short period is called ______.
`"dN"/"dt" = "rN" (("K"- "N")/"K")` in logistic growth "K" represents:
The density of a population in a habitat per unit area is measured in different units. Write the unit of measurement against the following:
Banyan
The density of a population in a habitat per unit area is measured in different units. Write the unit of measurement against the following:
Fish

Label the three tiers 1, 2, 3 given in the above age pyramid.
Draw an age pyramid for the ‘zero population growth rate’.
The following diagrams are the age pyramids of different populations. Comment on the status of these populations.

What would be the best method to measure the total population density of a dense bacterial culture in a petridish and why?

Identify the type of pyramid given above. Write the identifying feature on the basis of which you identified it.
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.
