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Biology LibreTexts

24: Ecology

  • Page ID
    17812
  • This chapter introduces the fundamentals of ecology, describes terrestrial and aquatic biomes, and outlines ecosystem processes and their value to humans. The chapter also describes interspecific relationships in communities, how energy flows through ecosystems, and how matter is recycled through ecosystems.

    • 24.1: Case Study - The Web of Life
      Camille grew up in a rural farming community, and both of her parents worked on a local farm. When pesticides were being applied to the crops, her parents had to use special protective equipment such as coveralls, gloves, and respirators. This is because many pesticides, which are substances that protect plants from damage and destruction by pests such as insects, can be hazardous to human health.
    • 24.2: Introduction to Ecology
      Ecology is the study of how living things interact with each other and with their environment. Although it is a science in its own right, ecology has areas of overlap with many other sciences, including biology, geography, geology, and climatology.
    • 24.3: Ecosystems
      An ecosystem is a set of interacting components that form a complex whole including all of its living things and its nonliving environment. The nonliving environment includes abiotic factors such as temperature, water, sunlight, and minerals in the soil. A community is the biotic part of an ecosystem.
    • 24.4: Community Relationships
      A community is the biotic part of an ecosystem and consists of all the populations of all the species that live and interact in the ecosystem. Populations of different species generally interact in a complex web of relationships.
    • 24.5: Energy in Ecosystems
      There are two basic types of organisms in terms of how they obtain energy: autotrophs and heterotrophs. Autotrophs (a.k.a producers) are organisms that use energy directly from the sun or from chemical bonds. Heterotrophs (a.k.a consumers) are organisms that obtain energy from other living things.
    • 24.6: Cycles of Matter
      The water and chemical elements that organisms need continuously cycle through ecosystems, passing repeatedly through their biotic and abiotic components. These cycles are called biogeochemical cycles because they are cycles of chemicals that include both organisms (bio) and abiotic components such as the ocean or rocks (geo).
    • 24.7: Introduction to Human Populations
      We know more about the human population and how it has grown than we know about the population of any other species thanks to demography, which is the scientific study of human populations. Demography encompasses the size, distribution, and structure of populations.
    • 24.8: Population Dynamics
      Populations are dynamic. They are continuously gaining individuals through births and losing individuals through deaths. Populations may also gain or lose significant numbers of individuals through migration, when people either enter or leave a population. All of these factors together determine whether and how quickly a population grows.
    • 24.9: Climate Change
      There is no longer any doubt that our planet is growing warmer and that human actions are the primary cause. There is also no question that if we don't do something about it soon, the consequences will be devastating.
    • 24.10: Case Study Organic Conclusion and Chapter Summary
      Camille, who you read about in the beginning of the chapter, asks herself questions like this whenever she goes food shopping. If organic agricultural practices are significantly better for the environment, she would like to buy organic food products at least some of the time. But are they better? And if so, how?

    Thumbnail: Bumblebee pollinating Aquilegia vulgaris. Image used with permission (CC BY-SA 3.0 Unported; Roo72).