Ecological Levels
Ecological levels refer to the hierarchical organization of biological systems, from individual organisms to the entire biosphere. These levels include individuals, populations, communities, ecosystems, and the biosphere. Each level represents a different scale of ecological organization and plays a role in understanding the interactions and dynamics of living organisms and their environment.
6 Key excerpts on "Ecological Levels"
eBook - ePub- Jeffrey W. Bloom(Author)
- 2010(Publication Date)
- Routledge(Publisher)
...The higher up the hierarchy, the less effect you notice. As a result, the functional patterns, such as energy flow pathways (see subection 3.5), at higher levels tend to stabilize the whole system. As you read through the following descriptions of these levels, it is important to keep in mind that the definitions and descriptions of each level are somewhat tentative or even vague. From one perspective, ecologists are still arguing about how to define many of these levels. From another perspective, the “boundaries” or distinctions are often somewhat fuzzy and dependent upon the specific context. Organism The individual organism is the smallest unit of analysis in ecology. The variety of these organisms is described in Section 2. They include bacteria, archaebacteria, protists, fungi, plants, and animals. Population The concept of population has to do with all of the individuals of one species that live within the local community of living organisms. Although any particular species may be spread over a larger region, the population of that species refers to only those individuals that live in a specific area. Community or Biotic Community A biological or biotic community includes all of the populations of species that live in a particular area. A forest contains a variety of different organisms. All these organisms comprise the forest community. However, the notion of community can be associated with a notion of scale. Even though we may view a forest as a community at a large scale, each individual tree contains its own community of organisms, such as bacteria, fungi, lichens, and certain insects. In fact, we as human beings have our own communities of organisms living all over our internal and external surfaces (e.g., mites, bacteria, fungi). Communities are characterized by a variety of different species, which interact and affect one another in various ways...
eBook - ePub- Johann F. Moltmann, D.M. Rawson(Authors)
- 2020(Publication Date)
- CRC Press(Publisher)
...3 BASIC ECOLOGICAL PROBLEMS OF ECOTOXICOLOGY 3.1 THE LEVELS OF ORGANIZATION OF BIOLOGICAL SYSTEMS The objects of ecological study are organisms, each of which represents a complex system of cells and organs. These organisms, in turn, are organized into larger units (populations, communities, ecosystems). Nature’s division into different levels of organization (Figure 3.1) is not arbitrary and has implications for the acquisition of knowledge in all areas of biology (O’NEILL et al., 1986). With each higher level of organization (cell → organism → population → ecosystem), it becomes increasingly difficult to establish clear-cut relationships based on cause and effect, or to maintain an overview of the growing abundance of such relationships. Although the biochemical reactions in cells are manifold and complex, they can be analyzed at this level and are similar in many cells. Interactions between organs can also be explained at the level of individual organisms. But any prognosis of individual development and behavior is necessarily imprecise. For all practical purposes, populations can only be analyzed statistically. On the population level, integrative parameters (e.g. fertility) are being observed to a greater degree in experimental settings, although the changes in such parameters cannot be explained in detail; nor is it necessary to do so. This approach cannot be applied ad infinitum at the ecosystem level because the number of ecosystems which could reasonably be compared on the basis of statistical data is too low...
eBook - ePub- Oswald J. Schmitz(Author)
- 2013(Publication Date)
- Island Press(Publisher)
...Natural ecological systems differ from the container system in that they are comprised of vastly more species with many more interdependencies than those found in the glass container. Understanding these complex interdependencies is the fundamental purpose of that subfield of biology known as ecology. What Is Ecology? Ecology is a science aimed at understanding: The processes by which living organisms interact with each other and with the physical and chemical components of their surrounding environment. The way those processes lead to patterns in the geographical distribution and abundance of different kinds of organisms. The result of the process leading to a pattern is the assembly of a natural economy. In ecology such a natural economy is formally called an ecosystem. Ecosystems encapsulate many forms of biological diversity (also called biodiversity). Biodiversity results from a variety among individuals comprising a species owing to sex, age, and genetic differences among those individuals. It also stems from differences between species living together in a geographic location. For example, species may differ in their functional roles (e.g., plant, herbivore, carnivore) and the efficiency with which each carries out its function in different environmental conditions. Biodiversity also arises from the myriad ways that species are linked to each other in ecosystems. As a consequence of these many forms of biodiversity, there is considerable complexity underlying the structure of ecosystems.The challenge in ecology is resolving this complexity. Biodiversity results from a variety among individuals comprising a species due to sex, age, and ge- netic differences; from differences between species living together in a geographic location; and from the myriad ways that species are linked to each other in ecosystems. As a consequence of these many forms of biodiversity, there is consider- able complexity underlying the structure of ecosystems...
eBook - ePubFoundations of Ecology
Classic Papers with Commentaries
- Leslie A. Real, James H. Brown(Authors)
- 2012(Publication Date)
- University of Chicago Press(Publisher)
.... .. It is the systems so formed which, from the point of view of the ecologist, are the basic units of nature on the face of the earth. . .. These ecosystems, as we may call them, are of the most various kinds and sizes. They form one category of the multitudinous physical systems of the universe, which range from the universe as a whole down to the atom.” Tansley goes on to discuss the ecosystem as a category of rank equal to the “biome” (Clements, ’16), but points out that the term can also be used in a general sense, as is the word “community.” The ecosystem may be formally defined as the system composed of physical-chemical-biological processes active within a space-time unit of any magnitude, i.e., the biotic community plus its abiotic environment. The concept of the ecosystem is believed by the writer to be of fundamental importance in interpreting the data of dynamic ecology. TROPHIC DYNAMICS Qualitative food-cycle relationships Although certain aspects of food relations have been known for centuries, many processes within ecosystems are still very incompletely understood. The basic process in trophic dynamics is the transfer of energy from one part of the ecosystem to another. All function, and indeed all life, within an ecosystem depends upon the utilization of an external source of energy, solar radiation. A portion of this incident energy is transformed by the process of photosynthesis into the structure of living organisms. In the language of community economics introduced by Thienemann (’26), auto-trophic plants are producer organisms, employing the energy obtained by photosynthesis to synthesize complex organic substances from simple inorganic substances. Although plants again release a portion of this potential energy in catabolic processes, a great surplus of organic substance is accumulated...
eBook - ePubDynamic Aquaria
Building Living Ecosystems
- Walter H. Adey, Karen Loveland(Authors)
- 2011(Publication Date)
- Academic Press(Publisher)
...CHAPTER 12 Community Structure Biodiversity in Model Ecosystems Individual organisms, as part of species populations, in a microcosm or mesocosm, interact with each other, and together with the physical environment, to form an ecosystem. The development of an ecosystem, whether in a newly created environment in the wild or in a model, is called self-organization. Ultimately, the metabolic and behavioral information encoded in the genes of each individual determines how each individual will interact with other individuals of its own and other species and with its environmental parameters. In this chapter, we specifically treat the subject of biodiversity, the number of families, genera and species in an ecosystem, and particularly how those species, as populations, structurally relate to each other in any biological community that we may wish to model. It is widely recognized today that the Earth’s biodiversity is rapidly being reduced due to the numbers of humans and their economic activities (Reaka-Kudla, 1996). To understand what a simple species count in an ecosystem model should be and is, in reality, it is necessary to understand the reasons for biodiversity in wild ecosystems. Although the reasons are complex, enough information has been collected, particularly in the past 10–20 years, to provide the framework for that understanding. In a sense, many of Earth’s ecosystems have become models, increasingly limited by the ever-expanding and ever-more intrusive bounds of human society. Understanding how to manage biodiversity in microcosms and mesocosms can provide us with the ability to further understand and manage the biodiversity of the planet at large. Models can be the experimental tools that assist us to develop a rationale for living with the incredible and incredibly valuable biological diversity that 3–4 billion years of evolution has produced...
eBook - ePubHuman Ecology
Basic Concepts for Sustainable Development
- Gerald G Marten(Author)
- 2010(Publication Date)
- Routledge(Publisher)
...4 Ecosystems and Social Systems as Complex Adaptive Systems Ecosystems and social systems are complex adaptive systems : complex because they have many parts and many connections between the parts; adaptive because their feedback structure gives them the ability to change in ways that promote survival in a fluctuating environment. How can we understand human–ecosystem interaction when social systems and ecosystems are so overwhelmingly complex? The answer lies in emergent properties : the distinctive features and behaviour that ‘emerge’ from the way that complex adaptive systems are organized. Once aware of emergent properties, it is easier to ‘see’ what is really happening. Emergent properties are cornerstones for comprehending human–ecosystem interactions in ways that provide insights for sustainable development. This chapter will begin by explaining the concept of emergent properties. It will then describe three significant examples of emergent properties in detail: Self-organization. Stability domains. Complex system cycles. Later chapters will describe additional emergent properties of ecosystems and social systems. Hierarchical Organization And Emergent Properties Biological systems have a hierarchy of organizational levels that extends from molecules and cells to individual organisms, populations and ecosystems. Every individual plant and animal is a collection of cells; every population is a collection of individual organisms of the same species; and every ecosystem consists of populations of different species. The most important levels of biological organization for human ecology are populations and ecosystems. Each level of biological organization from molecules to ecosystems has characteristic behaviours which emerge at that level. These distinct behaviours, called emergent properties, function synergistically at each level of organization to give that level a life of its own which is greater than the sum of its parts...
