A biologist studied the population of rats in a granary. He found the average natality was 280, average mortality was 200, immigration was 40 and emigration was 50. The net increase in population is:
Show Hint
- 80
- 70
- 10
- 90
The Correct Option is B
Solution and Explanation
= (280 + 40) − (200 + 50)
= 320 − 250
= 70
Top Questions on Organisms and Populations
Answer the following questions:
- [(i)] Describe the population growth curve applicable in a population of any species in nature that has unlimited resources at its disposal.
- [(ii)] Explain the equation of this growth curve.
- [(iii)] Name the growth curve and depict a graphical plot for this type of population growth.
- [(i)] Explain the conclusion drawn by Alexander von Humboldt during his extensive explorations in the wilderness of South American jungles.
- [(ii)] Give the equation of the Species-Area relationship.
- [(iii)] Draw a graphical representation of the relation between species richness and area for a wide variety of taxa such as birds, bats, etc.
- CBSE CLASS XII - 2025
- Biology
- Organisms and Populations
Student to attempt either option (A) or (B):
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OR
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- Biology
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Student to attempt either option (A) or (B):
(A) How is the interaction between Ophrys and its specific bee pollinator one of the best examples of co-evolution? Explain.
OR
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- Biology
- Organisms and Populations
- (a) Draw a graph for a population whose population density has reached the carrying capacity.
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(c) Draw a growth curve where resources are not limiting for the growth of a population and give its equation.
- CBSE CLASS XII - 2025
- Biology
- Organisms and Populations
(a) (i) Describe the population growth curve applicable in a population of any species in nature that has limited resources at its disposal.
(ii) Give the equation of this growth curve.
(iii) Name the growth curve and depict a graphical plot for this type of population growth.OR
(b) (i) Explain the Species-Area relationship within a natural forest and also predict the nature of the graph when species richness is plotted against the area for a wide variety of taxa.
(ii) Depict the graphical relationship between species richness and area.
(iii) Give the equation of the Species-Area relationship for a wide variety of taxa on a logarithmic scale.- CBSE CLASS XII - 2025
- Biology
- Organisms and Populations
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Inspired by the success of Chandrayaan-3, the Chief Scientist at ‘Space Rover’ a private research group, decided to send some innovative ideas regarding the mission to the Chief Scientist of Chandrayaan-3. The Chief Scientist at ‘Space Rover’ formed four groups for the same. As it was an intellectual activity of thinking rather than doing, these four groups started interacting with each other and friendships developed. On the basis of their interaction and friendship, some members from each group formed ‘Entertainment Through Reading’ group which showed conformity in terms of their interest. ‘Entertainment Through Reading’ group had no written rules, was unstable in form and scope and had no fixed lines of communication. The members of this group enhanced the morale of each other, enjoyed drinking coffee together, read books, served different issues of their work areas and provided support to each other. Ultimately this group developed some innovative ideas which were sent by ‘Space Rover’ to the Chief Scientist of Chandrayaan-3. Though this group was formed for recreation but it contributed towards fulfillment of organisational objectives.
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(ii) Production cycle
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Explain the following points of significance of principles of management:
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