Organisms and Populations — Class 12 Biology NCERT Solutions (Free)

Free step-by-step NCERT solutions for Class 12 Biology chapter "Organisms and Populations" — 8 important questions with detailed answers for CBSE board exam preparation.

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TL;DR: Free step-by-step NCERT solutions for Class 12 Biology chapter "Organisms and Populations" — 8 important questions with detailed answers for CBSE boar…

Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated Jul 23, 2026

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Key Questions Covered:

Define population and community.
What are the characteristics of a population? Explain population density and …
Describe the different types of age structure in populations and their signif…
What are limiting factors? Explain density-dependent and density-independent …
Explain population growth models: exponential and logistic growth.
What are life tables and survivorship curves? Give their ecological significa…
+ 2 more questions in the full chapter

Solutions Summary:

Question	Status
Define population and community.	✓ Solved
What are the characteristics of a population? Explain pop…	✓ Solved
Describe the different types of age structure in populati…	✓ Solved
What are limiting factors? Explain density-dependent and …	✓ Solved
Explain population growth models: exponential and logisti…	✓ Solved
What are life tables and survivorship curves? Give their …	✓ Solved

Showing 6 of 8 questions

Q1: Define population and community.

POPULATION: A population is a group of individuals of the same species living in the same geographical area at the same time. Members of a population can interbreed and share a common gene pool. Example: All lions in Gir Forest form a population. COMMUNITY: A community is a group of different populations of different species living and interacting in the same geographical area at the same time. It consists of all the biotic factors in an ecosystem. Example: All plants, animals, and microorganis...

Q2: What are the characteristics of a population? Explain population density and population distribution.

CHARACTERISTICS OF A POPULATION: 1. GENE POOL: - All genes present in a population - Shows genetic variation among individuals - Foundation for evolution and adaptation 2. GENE FREQUENCY: - Proportion of each allele in gene pool - Expressed as percentage or decimal - Changes over generations 3. BIRTH RATE (NATALITY): - Number of new individuals born per unit time - Expressed as number per 1000 individuals per year - Increases population size 4. DEATH RATE (MORTALITY): - Number of individuals...

Q3: Describe the different types of age structure in populations and their significance.

Age structure (age pyramid or age distribution) refers to the proportion of individuals of different age groups in a population. It determines population growth patterns and reproductive potential.

Q4: What are limiting factors? Explain density-dependent and density-independent factors.

Limiting factors are environmental factors that restrict population growth and prevent indefinite increase. They determine carrying capacity of environment.

Q5: Explain population growth models: exponential and logistic growth.

Population growth models describe how populations change over time under different environmental conditions.

Q6: What are life tables and survivorship curves? Give their ecological significance.

Life tables are age-specific demographic tables that track survival and mortality of individuals. Survivorship curves graphically represent survival patterns.

Showing 6 of 8 questions. Visit the full page for complete solutions.