CBSE Grade-12 Biology | 11. ORGANISMS AND POPULATIONS by Pavan | Learn Smarter
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11. ORGANISMS AND POPULATIONS

11. ORGANISMS AND POPULATIONS

The chapter explores the complexity and diversity of life, especially through the lens of ecology, focusing on populations within ecosystems. It discusses attributes of populations, mechanisms of population growth, various interactions among species, and the implications of these interactions on ecological balance. Key concepts such as predation, competition, and mutualism are highlighted, emphasizing the interconnectedness of organisms in their habitats.

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Sections

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  1. 11
    Organisms And Populations

    This section discusses the concepts of populations in ecology, highlighting...

  2. 11.1

    This section explores the concept of populations within ecology, including...

  3. 11.1.1
    Population Attributes

    This section discusses the defining attributes of populations in ecology,...

  4. 11.1.2
    Population Growth

    Population growth is a dynamic process influenced by birth rates, death...

  5. 11.1.3
    Life History Variation

    This section discusses how populations evolve reproductive strategies to...

  6. 11.1.4
    Population Interactions

    Population interactions involve the interrelationship between different...

  7. 11.1.4.1

    Predation is a significant ecological interaction where one organism (the...

  8. 11.1.4.2

    Competition describes the interactions between species where both...

  9. 11.1.4.3

    Parasitism is a type of interaction between two different species where one...

  10. 11.1.4.4
    Commensalism

    Commensalism is a type of interspecific interaction where one species...

  11. 11.1.4.5

    Mutualism is a type of interaction where both species involved benefit from...

  12. 11.2

    Ecology is the study of interactions between living organisms and their...

  13. 11.3

    This section presents exercises that focus on key concepts of population...

What we have learnt

  • Ecology is the study of the relationships between organisms and their environment, organized into populations, communities, and ecosystems.
  • Population attributes differ from individual characteristics, including birth rates, death rates, sex ratios, and age distributions.
  • Interactions among species can significantly influence community dynamics, including competition, predation, mutualism, and parasitism.

Key Concepts

-- Population Density
The number of individuals within a specific area, which influences ecological dynamics.
-- Exponential Growth
A growth pattern where populations increase rapidly in size when resources are abundant.
-- Logistic Growth
A growth pattern that occurs when a population's growth rate decreases as it approaches its carrying capacity.
-- Mutualism
An interaction where both species benefit, often involving co-evolution.
-- Predation
An interaction where one organism (predator) feeds on another organism (prey), transferring energy across trophic levels.
-- Commensalism
An interaction where one species benefits and the other is neither helped nor harmed.

Additional Learning Materials

Supplementary resources to enhance your learning experience.