How is diapause different from hibernation?
Solution and Explanation
Diapause is a stage of suspended development to cope with unfavourable conditions. Many species of Zooplankton and insects exhibit diapause to tide over adverse climatic conditions during their development.
Hibernation or winter sleep is a resting stage where in animals escape winters (cold) by hiding themselves in their shelters. They escape the winter season by entering a state of inactivity by slowing their metabolism. The phenomenon of hibernation is exhibited by bats squirrels and other rodents.
Top Questions on Organisms and Populations
- (a) Draw a graph for a population whose population density has reached the carrying capacity.
(b) Out of the two population growth curves, which one is considered a more realistic for most populations? Why?
(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
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
(B) Arrange the given important steps of decomposition in their correct order of occurrence in the breakdown of complex organic matter and explain the fourth step in the process.- CBSE CLASS XII - 2025
- Biology
- Organisms and Populations
- 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:
- CBSE CLASS XII - 2025
- Biology
- 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):
(A) Explain how the interaction between a fig tree and its tight one-to-one relationship with the pollinator species of wasp is one of the best examples of mutualism.
OR
(B) Correctly depict (also indicate the trophic level) and describe the ecological pyramid of number with 32 birds dependent on 20 insects feeding on one banyan tree.- CBSE CLASS XII - 2025
- Biology
- Organisms and Populations
Questions Asked in CBSE CLASS XII exam
- For a positive constant \( a \), differentiate \( \left( t + \frac{1}{t} \right)^a \) with respect to \( t \), where \( t \) is a non-zero real number.
- CBSE CLASS XII - 2025
- Differentiation
Complete and balance the following chemical equations: (a) \[ 2MnO_4^-(aq) + 10I^-(aq) + 16H^+(aq) \rightarrow \] (b) \[ Cr_2O_7^{2-}(aq) + 6Fe^{2+}(aq) + 14H^+(aq) \rightarrow \]
- CBSE CLASS XII - 2025
- Redox Reactions
- Pulkit and Ravinder were partners in a firm sharing profits and losses in the ratio of 3 : 2. Sikander was admitted as a new partner for \( \frac{1}{5} \)th share in the profits of the firm. Pulkit, Ravinder and Sikander decided to share future profits in the ratio of 2 : 2 : 1. Sikander brought Rs 5,00,000 as his capital and Rs 10,00,000 as his share of premium for goodwill. The amount of premium for goodwill that will be credited to the old partners' capital accounts will be :
- CBSE CLASS XII - 2025
- Partnership Accounts
- What is the term used for the milk produced during the initial days of lactation?
- CBSE CLASS XII - 2025
- human health and disease
- Find: \[ I = \int (\sqrt{\tan x} + \sqrt{\cot x}) dx. \]
- CBSE CLASS XII - 2025
- Integration by Parts
Concepts Used:
Organisms and their Environments
Ecology is the branch of biology that involves the study of the interactions that takes place between an organism and its environment. Any biological organization consists of 4 levels, namely, Organisms, Populations, Biomes, and Communities.
Organisms:
An Organism is an attached living system that lives in an environment. They are able to retain specific behaviours and structure such as bacteria, fungi, plants, animals, and humans. A population is formed by the collection of all these organisms. The collection of population forms a community that helps in the operation of ecosystems.
Environment:
The study of the interaction of organisms in an area with the surrounding environment is Ecology. This interaction constitutes an overall adaptation of the organisms to their environment that also includes the continuity of species.
The environment comprises of both biotic (living things) and abiotic components (non-living things)
Food Chain:
Food Chain is the transfer of food energy from the plant source through a series of organisms that consume and are consumed.
Grass(Producer) → Deer(Herbivore) → Tiger(Carnivore), Grass(Producers) → Insect(Herbivores) → Frog(Carnivores) → Snake(Secondary Carnivore).
Food Web:
Food web is the interlocking pattern of multiple food chains in the ecosystem. In this, many food chains are interconnected and there are increased possibilities of eating and getting eaten by different organisms of various species.