Population Density Changes Over Time — NEET Biology
📚 Practice ConceptSo, if N is the population density at time t, then its density at time t + 1 is
Which of the above statements are correct? S1: Natality refers to the per capita number of births in a population during a specific time period. S2: Population density at time (t+1) can be precisely represented as N(t+1) = N(t) + [(Births + Emigration) – (Deaths + Immigration)]. S3: Immigration becomes a more significant factor for population growth than birth rates when a new habitat is being colonised. S4: Mortality contributes to an increase in population density, while emigration causes a decrease. S5: For certain ecological investigations, relative population densities, such as the number of fish caught per trap, serve the purpose equally well. S6: Population ecology serves as an important area linking ecology to population genetics and evolution.
View solution & NCERT explanation
Correct answer: D — S1, S3, S5 and S6 only
This question evaluates the understanding of population attributes, specifically the factors influencing population growth and density, and their broader ecological significance as outlined in NCERT. S1: Correct. NCERT defines birth rates (natality) as 'per capita births' in a population during a given period. S2: Incorrect. The correct equation for population density at time t+1 is N(t+1) = N(t) + [(Births + Immigration) – (Deaths + Emigration)]. The formula presented in the statement incorrectly swaps 'Immigration' and 'Emigration' in the positive and negative terms. S3: Correct. NCERT states, 'if a new habitat is just being colonised, immigration may contribute more significantly to population growth than birth rates.' S4: Incorrect. Mortality (deaths) contributes to a *decrease*, not an increase, in population density, while emigration also causes a decrease. S5: Correct. NCERT states, 'Sometimes, for certain ecological investigations, there is no need to know the absolute population densities; relative densities serve the purpose equally well. For instance, the number of fish caught per trap is good enough measure of its total population density in the lake.' S6: Correct. NCERT highlights that 'Population ecology is, therefore, an important area because it links ecology to population genetics and evolution.' Therefore, statements S1, S3, S5, and S6 are correct. Option 'B' correctly identifies these four statements as correct. Other options contain incorrect statements or miss correct ones. This concept is fundamental to understanding how populations change over time and the factors driving these dynamics, linking ecological studies to broader evolutionary principles.
What does NCERT say about So if N population?
Has this concept appeared in NEET?
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