Organisms and Populations
ICSE · Class 12 · Biology
Complete topic list for Organisms and Populations in ICSE Class 12 Biology. Key concepts, sub-topics, and what to focus on for board exams.
Interactive on Super Tutor
Studying Organisms and Populations? Get the full interactive chapter.
Quizzes, flashcards, AI doubt-solver and a step-by-step study plan — built for syllabus and more.
1,000+ Class 12 students started this chapter today

Super Tutor has 5+ illustrations like this for Organisms and Populations alone — flashcards, concept maps, and step-by-step visuals.
See them allTopics in Organisms and Populations
Levels of Ecological Organisation
- Ecology deals with five levels of biological organisation: organism, population, community, ecosystem, and biosphere.
- An organism is any form of life, with cell as its basic unit.
- A population is a group of interacting individuals of the same species living in a specific physical place, the habitat.
Population Interactions
- Interspecific relationships occur between different species.
- Positive interactions include commensalism, proto-cooperation, and mutualism.
- Negative interactions include predation, parasitism, competition, and amensalism.
Examples of Positive and Negative Interactions
- Lianas, epiphytes, and epizoans are examples of commensals.
- Epiphytes grow perched on other plants only for support and not for water or nutrient supply.
- Epizoans are plants growing on the surface of animals.
Population Density, Birth Rate, Death Rate, and Growth
- Population density refers to the number of individuals present in unit area at a given time.
- Population growth depends on births, deaths, immigration, and emigration.
- Natality is the birth rate and mortality is the death rate.
Key Concepts
Central concept: Organisms and Populations
Frequently Asked Questions
What are the important topics in Organisms and Populations for ICSE Class 12 Biology?
How to score full marks in Organisms and Populations — ICSE Class 12 Biology?
Sources & Official References
Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.
More resources for Organisms and Populations
Practice Quiz
Test yourself with a quick quiz
Important Questions
Practice with board exam-style questions
Revision Notes
Key points for last-minute revision
Formula Sheet
All formulas in one place
Chapter Summary
Understand the chapter at a glance
Concept Maps
See how topics connect visually
Study Plan
Step-by-step plan to ace this chapter
Flashcards
Quick-fire cards for active recall
NCERT Solutions
Every textbook question solved step by step
For serious students
Get the full Organisms and Populations chapter — for free.
Quizzes, flashcards, AI doubt-solver and a step-by-step study plan for ICSE Class 12 Biology.