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

  • 11

    Organisms And Populations

    This section discusses the concepts of populations in ecology, highlighting their attributes, growth patterns, and interactions within ecosystems.

    Learning Practice

  • 11.1

    Populations

    This section explores the concept of populations within ecology, including their attributes, growth patterns, interactions, and the significance of these dynamics in understanding biological processes.

    Learning Practice

  • 11.1.1

    Population Attributes

    This section discusses the defining attributes of populations in ecology, emphasizing their characteristics compared to individual organisms.

    Learning Practice

  • 11.1.2

    Population Growth

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

    Learning Practice

  • 11.1.3

    Life History Variation

    This section discusses how populations evolve reproductive strategies to maximize their fitness in response to various selection pressures.

    Learning Practice

  • 11.1.4

    Population Interactions

    Population interactions involve the interrelationship between different species in an ecosystem, significantly impacting their survival and population dynamics.

    Learning Practice

  • 11.1.4.1

    Predation

    Predation is a significant ecological interaction where one organism (the predator) consumes another (the prey), affecting population dynamics and energy transfer within ecosystems.

    Learning Practice

  • 11.1.4.2

    Competition

    Competition describes the interactions between species where both participants face detriment due to fighting for similar resources.

    Learning Practice

  • 11.1.4.3

    Parasitism

    Parasitism is a type of interaction between two different species where one benefits at the expense of the other.

    Learning Practice

  • 11.1.4.4

    Commensalism

    Commensalism is a type of interspecific interaction where one species benefits while the other is neither harmed nor benefited.

    Learning Practice

  • 11.1.4.5

    Mutualism

    Mutualism is a type of interaction where both species involved benefit from their relationship, which is essential for various ecological processes.

    Learning Practice

  • 11.2

    Summary

    Ecology is the study of interactions between living organisms and their environment, focusing on populations and their dynamics.

    Learning Practice

  • 11.3

    Exercises

    This section presents exercises that focus on key concepts of population dynamics, interactions among species, and ecological principles.

    Learning Practice

References

NCERT Study Material

Class Notes

Memorization

What we have learnt

  • Ecology is the study of the...
  • Population attributes diffe...
  • Interactions among species ...

Final Test

Revision Tests