Organisms and Populations
CBSE Class 12 Biology · every board question from this chapter, 2022–2026 · 17 of them repeated across years
- Which of the following is an important parameter for assessing the impact of any biotic or abiotic factor on population growth?2026
- Choose a correct option that shows an interaction in which one species benefits while the other is neither harmed nor benefitted.2026
- Cattle or goats are never seen browsing on the weed, Calotropis. Select the correct option for the reason.2026
- Assertion: The interaction between a whale and the small barnacles on its back is considered as commensalism. Reason (R): In the…2026
- In some cases, measuring population density by counting individuals may not be feasible. Mention two other parameters that can be…2026asked 2×
- What is the carrying capacity of a species in a habitat? Explain the growth curve that takes this capacity into account.2026asked 3×
- Explain Gause's 'Competitive Exclusion Principle' with the help of a suitable example.2026asked 2×
- 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.…2026asked 2×
- Given below is an equation describing the growth pattern of a population: dN / dt=rN Mention the type of growth model or growth…2026
- The diagram below shows the distribution of two barnacle species, Chthamalus and Balanus on a rocky sea shore. When Balanus is…2026asked 3×
- A biologist studied the population of rats in a granary. He found the average natality was 280, average mortality was 200,…2025
- Draw a graph for a population whose population density has reached the carrying capacity. Out of the two population growth…2025asked 2×
- Read the following passage and answer the questions that follow: In nature, we rarely find isolated, single individuals of any…2025asked 3×
- (i) How does alien species invasion cause a decline in biodiversity? Explain. How have the following contributed to biodiversity…2025asked 2×
- (i) Describe the population growth curve applicable in a population of any species in nature that has limited resources at its…2025asked 3×
- (i) Describe the Species-Area relationship as observed by Alexander von Humboldt, for a wide variety of taxa in nature. (ii) Draw…2025asked 3×
- The population growth curve applicable for a population of beetles growing in nature under unlimited resource conditions…2024
- The population growth curve applicable for a population growing in a geometric fashion, when the resources are not limiting in…2024
- Read the four statements given below and select the option having two correct statements: (i) A lion eating a deer and a sparrow…2024
- The population growth curve applicable for a population growing in nature with limited resources available to them will be:2024
- Observe the population growth curve and answer the questions given below: State the conditions under which growth curve ‘A’ and…2024
- A specific plant species was introduced into Australia in 1920 and later it became invasive spreading over millions of hectares…2024
- Describe the mutualistic relationship that exists between the Mediterranean orchid Ophrys and a bee species.2024
- Describe how fig tree and wasp relationship is a spectacular example of mutualism.2024
- Read the following passage: Populations evolve to maximise their reproductive fitness in the habitat in which they live.…2024asked 3×
- Many copepods live on the body surface of marine fish. This relationship is an example of:2023
- A Tight one-to-one relationship between many species of fig tree and certain wasps is an example of -2023
- Interaction between clown fish living among the stinging tentacles of sea anemone is an example of -2023
- Identify the option that does not exhibit a parasitic relationship.2023
- Important attributes belonging to a population but not to an individual are: 1 (i) Birth rate and death rate (ii) Male and female…2023asked 3×
- Examples that show commensalism are: (i) An orchid growing on mango tree (ii) Cuckoo bird and crow (iii) Cuscuta growing on…2023
- Assertion: A species of wasp and a fig species cannot complete their life cycle without each other. Reason (R): While visiting…2023
- Assertion: A cattle egret and grazing cattle in close association is a classic example of commensalism. Reason (R): As grazing…2023
- Assertion: Cattle and goats are never seen browsing on Calotropis growing in abandoned fields. Reason (R): Cattle and goats avoid…2023
- List and explain any two factors that lead to a decrease in the population density of an area.2023
- Explain the following population interactions with the help of one example each: Brood Parasitism Co-evolution of mutualists2023asked 3×
- (i) Write the observations made at the end of Connell's field experiment on barnacles on the rocky sea coasts of Scotland. (ii)…2022asked 3×
- State two morphological attributes observed in the leaves of desert plants that enable them to survive in extreme conditions in…2022
- To survive unfavourable conditions, some organisms hibernate and others go into aestivation. How is hibernation different from…2022
- Explain the two physiological attributes which enable a kangaroo rat to survive in desert conditions.2022
- The figures given below show the results of a lab experiment in which two microbial species A and B belonging to same genus were…2022
- Write the best method to measure the population density of a single Banyan tree in comparison to 20 Parthenium weeds in a forest…2022
- Mammals are capable of maintaining homeostasis. But, very few smaller animals can survive in polar regions. Give reasons.2022
- Study the given graphs (X) and (Y) depicting the annual variation in solar radiation on Earth from January to December and answer…2022asked 3×
- Why are predators considered to be 'prudent' in nature? Explain.2022
- What would be the best method to measure the total population density of a dense bacterial culture in a petridish and why?2022
- The graphs given below, A and B, represent population of elephants in two different National Parks (a hypothetical situation) at…2022asked 3×
- What would be the best method to measure the total population density of the number of fishes in river and why?2022
- Study the graph given below, showing the population growth curves 'A' and 'B' respectively. Answer the following questions: What…2022asked 2×
- What does the equation dN / dt=rN express in terms of population growth? Write the significance of 'r' in a population survey.2022
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