Organisms and Populations — Class 12 Maharashtra HSC Biology revision notes
A 8-page visual revision sheet for Organisms and Populations, written for Class 12 Maharashtra HSC Biology. Formulas, diagrams and the traps that cost marks, laid out to be read the night before rather than the term before. Free, and it opens inside CapCompass.
Page 1 as PDF
Organisms and Populations in one look
how one body copes with its habitat, and how a whole population does the same math differently
Ecological Hierarchy
- ecology: interactions among organisms, and between organisms and their abiotic environment
- term first used by Reiter, given substance by E. Haeckel (1865)
- four sequential levels of increasing complexity: organism, population, community, biome
- a population: organisms of the same kind sharing a geographical area
- several populations interacting in one area form a community
- a biome: a large regional unit set by climate, with its own major vegetation and fauna
- six major terrestrial biomes exist worldwide, sorted by mean temperature and rainfall
- desert, grassland, tropical forest, temperate forest, coniferous forest, arctic/alpine tundra
Habitat vs Niche
- the physical place a species lives, defined by sunlight, rainfall, temperature, soil and other abiotic factors
- not species-specific, supports numerous species at once, contains many niches
- the functional role an organism plays: what it eats, how it interacts
- how it fulfils its needs (J. Grinnell, 1917)
- species-specific, supports a single species at a time
- colloquially: habitat is a postal address, niche is a profession
Page 1 of 8. The full sheet, all 8 pages, opens free in the app.
What this Organisms and Populations sheet covers
- Ecological Hierarchy
- Habitat vs Niche
- Habitat
- Niche
- Fundamental vs Realized Niche
- Major Abiotic Factors
- How an organism copes with a stressful environment
- Adaptations, Named
- CAM pathway
- Allen's rule
- Blubber
- Behavioural regulation
- Population Attributes
- Measuring population size
- Exponential growth: unlimited resources
- Population after one year
- Logistic growth: growth meets a ceiling
- When death rate wins
- Density-dependent vs Density-independent growth
- Density-dependent
- Density-independent
- Reproductive strategies
- r-strategists vs K-strategists
- Interspecific Interactions, Who Wins
- Population interactions: who benefits, who's harmed
- Competition
- Parasitism
- Predation
- Named Examples
- Mutualism
- Commensalism
- Predation defence
- Traps that cost marks
- Tricks that save time
How CapCompass uses this sheet
These notes are not a standalone PDF. CapCompass plans Biology chapter by chapter against your real exam dates and free hours, and when the plan reaches Organisms and Populations the sheet opens inside the study block itself — at the page covering the sub-topic that block is on, with the timer still running. Revision arrives at the moment the plan says revise, instead of having to be gone looking for.
More Biology Class 12 revision notes
- Biodiversity, Conservation and Environmental Issues
- Biotechnology
- Control and Co-ordination
- Ecosystems and Energy Flow
- Enhancement of Food Production
- Human Health and Diseases
- Inheritance and Variation
- Molecular Basis of Inheritance
- Origin and Evolution of Life
- Plant Growth and Mineral Nutrition
- Plant Water Relation
- Reproduction in Lower and Higher Animals
- Reproduction in Lower and Higher Plants
- Respiration and Circulation