(a) List the different attributes that a population has and not an individual organism.
(b) What is population density ? Explain any three different ways the population density can be measured, with the help of an example each.
(a) Following are the attributes that a population has but an individual organism does not have:
(b) Population density means number of individuals present per unit area. Population density can be measured by determining the population size. The different methods to study population size are as follows:
(1) Indirect method: In this method the population density is measured without actually counting or seeing the organism. For examples – the tiger consensus in our national park and tiger reserves are often based on the pug marks and fecal pellets of the tiger.
Example: The number of Parthenium plants in a given area can be measured using the quadrat method.
(2) Direct observation: It involves the counting of organisms in the given area.
Example: In order to determine the number of bacteria growing in a Petri dish, their colonies are counted.
(a) Explain giving reasons why the tourists visiting Rohtang Pass or Mansarovar are advised to resume normal active life only after a few days of reaching there.
(b) It is impossible to find small animals in the polar regions. Give reasons.
(a) Name the two growth models that represent populations growth and draw the respective growth curves they represent.
(b) State the basis for the difference in the shape of these curves.
(c) Which one of the curves represent the human population growth at present ? Do you think such a curve is sustainable ? Give reason in support of your answer.
'Analysis of age-pyramids for human population can provide important inputs for long-term planning strategies.' Explain.
(a) Represent diagrammatically three kinds of age-pyramids for the human population.
(b) How does an age pyramid for human population at given point of time helps the policy makers in planning for the future.
