Ecological unit

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Ecological units refer to specific levels or degrees of organization within ecological systems. The units that are most commonly used and discussed within ecological systems are those at the levels of individuals, populations, communities, and ecosystems. [1] These terms help distinguish between very specific, localized interactions, such as those occurring at the individual or population level, and broader, more complex interactions that occur at the community and ecosystem levels, providing a framework for understanding ecological structure and processes at different scales. [2]

Contents

These ecological units are foundational to the field of ecology as they define and identify the key components and relationships within ecological systems at the different levels—providing cohesion in conversation and research. Additionally, these terms and the concept of ecological units as a whole are intertwined in ecological theory, understanding biodiversity, conservation strategies, and more. [1] However, these ecological units have been met with some disagreements over the inconsistencies in the exact terminology and its uses. Arguments over stem from conflicting views from four different areas: [1]

  1. Whether the units are defined statistically or via a network of interactions: Statistical definitions would mean that the ecological units are measured using measurable parameters, based on statistical values and criteria. A network of interactions entails that ecological units are defined by the relationships and dynamics between the organisms and environment. [1]
  2. Whether boundaries are drawn by topographical or process-related criteria: Topographical criteria means that the ecological boundaries are based on the physical and geographical features in the surroundings. Process-related criteria would focus on the ecological processes and interactions that occur at the level. [1]
  3. How high the required internal relationships are: This refers to the degree of intensity and complexity of the interactions and interconnectedness of the ecological unit. [1]
  4. Whether the ecological unit is perceived as a "real" entity or an abstraction by an observer: This argument debates if an ecological unit, despite having a name and loose definition, whether it is simply a measure for conceptual thought that helps in modeling, or whether it is definitive and seen as a concrete thing. [1]

Summary

Individual

The most basic ecological unit is at the individual level. At this level, singular organisms in a single species are the focus of reference. Studying individuals can help reinforce concepts in their physiology and behavior. Additionally, single individuals can be outliers in many ways, such as genetic variation, which can lead to questions about what triggered this change and to see whether it spreads to the remainder of the population. [3] It can be argued that studying individuals is insignificant and no concrete conclusions can be drawn about entire populations based on one individual. Regardless of this remark, individuals can still provide valuable insights into the broader dynamics of a species, as they offer a starting point for understanding the underlying processes of adaptation, survival, and reproduction. [4]

Population

The next level is populations—this refers to all individuals in a single species. Studying populations is crucial for understanding interactions within a species, between species, and with the surrounding environment. [5] It can also reveal similarities and differences between the same species in the same location or in different locations, helping to identify key variables that influence these variations. Changes within populations can often be attributed to some sort of survival pressure that is urging an evolutionary adaptation in order for the species to maintain itself. These pressures may include competition for resources, predation, climate changes, or disease outbreaks. [4] By examining population dynamics, scientists can gain insights into how species adapt over time, predict future changes, and make informed decisions about conservation efforts or managing ecosystems.

Community

Community would follow population in terms of hierarchical largeness. Community would be the collective dynamics amongst species and the habitat in which they live in. [6] Communities are most closely associated with habitats, which are more intimate than compared to ecosystems. Habitats signify a smaller, more specific region, while an ecosystem is a broader term that can encompass multiple habitats. An example of this could be that of the marine ecosystem which can be an umbrella term for all organisms living in oceanic conditions. [7] However, a habitat in the Gulf of Maine varies widely that the one of the Great Barrier Reef, despite both of them falling under the marine ecosystem term. [8] [9] This also means that the communities, the organisms that exist in these two different habitats, also differ.

Ecosystems

The last ecological unit is ecosystems. Ecosystems encompass the diverse and complex conditions of the Earth, including both biotic and abiotic components. [10] They often differ in geographic locations with respect to their position relative to the equator, relationship to altitude in which the location resides, seasonal trends, etc. [11] Some examples of ecosystems include marine/aquatic ecosystems, rainforests, tundras, savannas, etc. As mentioned above, not all habitats or communities within the same ecosystem are exactly the same, despite sharing the broader ecosystem classification. However, they do tend to share significant characteristics, such as similar climate conditions, predominant plant species, and types of interactions among organisms. These common features enable ecosystems to function cohesively, supporting particular ecological processes like nutrient cycling, energy flow, and species interactions, while still exhibiting unique variations across different regions and environmental contexts. [12]

Related Research Articles

<span class="mw-page-title-main">Ecology</span> Study of organisms and their environment

Ecology is the natural science of the relationships among living organisms and their environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere levels. Ecology overlaps with the closely related sciences of biogeography, evolutionary biology, genetics, ethology, and natural history.

<span class="mw-page-title-main">Theoretical ecology</span> Scientific discipline

Theoretical ecology is the scientific discipline devoted to the study of ecological systems using theoretical methods such as simple conceptual models, mathematical models, computational simulations, and advanced data analysis. Effective models improve understanding of the natural world by revealing how the dynamics of species populations are often based on fundamental biological conditions and processes. Further, the field aims to unify a diverse range of empirical observations by assuming that common, mechanistic processes generate observable phenomena across species and ecological environments. Based on biologically realistic assumptions, theoretical ecologists are able to uncover novel, non-intuitive insights about natural processes. Theoretical results are often verified by empirical and observational studies, revealing the power of theoretical methods in both predicting and understanding the noisy, diverse biological world.

<span class="mw-page-title-main">Ecological niche</span> Fit of a species living under specific environmental conditions

In ecology, a niche is the match of a species to a specific environmental condition. It describes how an organism or population responds to the distribution of resources and competitors and how it in turn alters those same factors. "The type and number of variables comprising the dimensions of an environmental niche vary from one species to another [and] the relative importance of particular environmental variables for a species may vary according to the geographic and biotic contexts".

<span class="mw-page-title-main">Biological interaction</span> Effect that organisms have on other organisms

In ecology, a biological interaction is the effect that a pair of organisms living together in a community have on each other. They can be either of the same species, or of different species. These effects may be short-term, or long-term, both often strongly influence the adaptation and evolution of the species involved. Biological interactions range from mutualism, beneficial to both partners, to competition, harmful to both partners. Interactions can be direct when physical contact is established or indirect, through intermediaries such as shared resources, territories, ecological services, metabolic waste, toxins or growth inhibitors. This type of relationship can be shown by net effect based on individual effects on both organisms arising out of relationship.

<span class="mw-page-title-main">Biological dispersal</span> Movement of individuals from their birth site to a breeding site

Biological dispersal refers to both the movement of individuals from their birth site to their breeding site and the movement from one breeding site to another . Dispersal is also used to describe the movement of propagules such as seeds and spores. Technically, dispersal is defined as any movement that has the potential to lead to gene flow. The act of dispersal involves three phases: departure, transfer, and settlement. There are different fitness costs and benefits associated with each of these phases. Through simply moving from one habitat patch to another, the dispersal of an individual has consequences not only for individual fitness, but also for population dynamics, population genetics, and species distribution. Understanding dispersal and the consequences, both for evolutionary strategies at a species level and for processes at an ecosystem level, requires understanding on the type of dispersal, the dispersal range of a given species, and the dispersal mechanisms involved. Biological dispersal can be correlated to population density. The range of variations of a species' location determines the expansion range.

<span class="mw-page-title-main">Ecosystem engineer</span> Ecological niche

An ecosystem engineer is any species that creates, significantly modifies, maintains or destroys a habitat. These organisms can have a large impact on species richness and landscape-level heterogeneity of an area. As a result, ecosystem engineers are important for maintaining the health and stability of the environment they are living in. Since all organisms impact the environment they live in one way or another, it has been proposed that the term "ecosystem engineers" be used only for keystone species whose behavior very strongly affects other organisms.

<span class="mw-page-title-main">Foundation species</span> Species that structures an ecology

In ecology, the foundation species are species that have a strong role in structuring a community. A foundation species can occupy any trophic level in a food web. The term was coined by Paul K. Dayton in 1972, who applied it to certain members of marine invertebrate and algae communities. It was clear from studies in several locations that there were a small handful of species whose activities had a disproportionate effect on the rest of the marine community and they were therefore key to the resilience of the community. Dayton’s view was that focusing on foundation species would allow for a simplified approach to more rapidly understand how a community as a whole would react to disturbances, such as pollution, instead of attempting the extremely difficult task of tracking the responses of all community members simultaneously. The term has since been applied to a range of organisms in ecosystems around the world, in both aquatic and terrestrial environments. Aaron Ellison et al. introduced the term to terrestrial ecology by applying the term foundation species to tree species that define and structure certain forest ecosystems through their influences on associated organisms and modulation of ecosystem processes.

Spatial ecology studies the ultimate distributional or spatial unit occupied by a species. In a particular habitat shared by several species, each of the species is usually confined to its own microhabitat or spatial niche because two species in the same general territory cannot usually occupy the same ecological niche for any significant length of time.

A functional group is a collection of organisms that share characteristics within a community. Ideally, these would perform equivalent tasks based on domain forces, rather than a common ancestor or evolutionary relationship. This could potentially lead to analogous structures that overrule the possibility of homology. More specifically, these beings produce resembling effects to external factors of an inhabiting system. Due to the fact that a majority of these creatures share an ecological niche, it is practical to assume they require similar structures in order to achieve the greatest amount of fitness. This refers to such as the ability to successfully reproduce to create offspring, and furthermore sustain life by avoiding predators and sharing meals.

<span class="mw-page-title-main">Functional ecology</span>

Functional ecology is a branch of ecology that focuses on the roles, or functions, that species play in the community or ecosystem in which they occur. In this approach, physiological, anatomical, and life history characteristics of the species are emphasized. The term "function" is used to emphasize certain physiological processes rather than discrete properties, describe an organism's role in a trophic system, or illustrate the effects of natural selective processes on an organism. This sub-discipline of ecology represents the crossroads between ecological patterns and the processes and mechanisms that underlie them.

<span class="mw-page-title-main">Ecological stoichiometry</span>

Ecological stoichiometry considers how the balance of energy and elements influences living systems. Similar to chemical stoichiometry, ecological stoichiometry is founded on constraints of mass balance as they apply to organisms and their interactions in ecosystems. Specifically, how does the balance of energy and elements affect and how is this balance affected by organisms and their interactions. Concepts of ecological stoichiometry have a long history in ecology with early references to the constraints of mass balance made by Liebig, Lotka, and Redfield. These earlier concepts have been extended to explicitly link the elemental physiology of organisms to their food web interactions and ecosystem function.

<span class="mw-page-title-main">Competition (biology)</span> Interaction where the fitness of one organism is lowered by the presence of another organism

Competition is an interaction between organisms or species in which both require one or more resources that are in limited supply. Competition lowers the fitness of both organisms involved since the presence of one of the organisms always reduces the amount of the resource available to the other.

The following outline is provided as an overview of and topical guide to ecology:

<span class="mw-page-title-main">Community (ecology)</span> Associated populations of species in a given area

In ecology, a community is a group or association of populations of two or more different species occupying the same geographical area at the same time, also known as a biocoenosis, biotic community, biological community, ecological community, or life assemblage. The term community has a variety of uses. In its simplest form it refers to groups of organisms in a specific place or time, for example, "the fish community of Lake Ontario before industrialization".

<span class="mw-page-title-main">Cross-boundary subsidy</span>

Cross-boundary subsidies are caused by organisms or materials that cross or traverse habitat patch boundaries, subsidizing the resident populations. The transferred organisms and materials may provide additional predators, prey, or nutrients to resident species, which can affect community and food web structure. Cross-boundary subsidies of materials and organisms occur in landscapes composed of different habitat patch types, and so depend on characteristics of those patches and on the boundaries in between them. Human alteration of the landscape, primarily through fragmentation, has the potential to alter important cross-boundary subsidies to increasingly isolated habitat patches. Understanding how processes that occur outside of habitat patches can affect populations within them may be important to habitat management.

<span class="mw-page-title-main">Plant ecology</span> The study of effect of the environment on the abundance and distribution of plants

Plant ecology is a subdiscipline of ecology that studies the distribution and abundance of plants, the effects of environmental factors upon the abundance of plants, and the interactions among plants and between plants and other organisms. Examples of these are the distribution of temperate deciduous forests in North America, the effects of drought or flooding upon plant survival, and competition among desert plants for water, or effects of herds of grazing animals upon the composition of grasslands.

Island ecology is the study of island organisms and their interactions with each other and the environment. Islands account for nearly 1/6 of earth’s total land area, yet the ecology of island ecosystems is vastly different from that of mainland communities. Their isolation and high availability of empty niches lead to increased speciation. As a result, island ecosystems comprise 30% of the world’s biodiversity hotspots, 50% of marine tropical diversity, and some of the most unusual and rare species. Many species still remain unknown.

<span class="mw-page-title-main">Evolving digital ecological network</span>

Evolving digital ecological networks are webs of interacting, self-replicating, and evolving computer programs that experience the same major ecological interactions as biological organisms. Despite being computational, these programs evolve quickly in an open-ended way, and starting from only one or two ancestral organisms, the formation of ecological networks can be observed in real-time by tracking interactions between the constantly evolving organism phenotypes. These phenotypes may be defined by combinations of logical computations that digital organisms perform and by expressed behaviors that have evolved. The types and outcomes of interactions between phenotypes are determined by task overlap for logic-defined phenotypes and by responses to encounters in the case of behavioral phenotypes. Biologists use these evolving networks to study active and fundamental topics within evolutionary ecology.

Eco-evolutionary dynamics refers to the reciprocal effects that ecology and evolution have on each other. The effects of ecology on evolutionary processes are commonly observed in studies, but the realization that evolutionary changes can be rapid led to the emergence of eco-evolutionary dynamics. The idea that evolutionary processes can occur quickly and on one timescale with ecological processes led scientists to begin studying the influence evolution has on ecology along with the affects ecology has on evolution. Recent studies have documented eco-evolutionary dynamics and feedback, which is the cyclic interaction between evolution and ecology, in natural and laboratory systems at different levels of biological organization, such as populations, communities, and ecosystems.

<span class="mw-page-title-main">Ontogenetic niche shift</span> Ecological phenomenon

Ontogenetic niche shift is an ecological phenomenon where an organism changes its diet or habitat during its ontogeny (development). During the ontogenetic niche shifting an ecological niche of an individual changes its breadth and position. The best known representatives of taxa that exhibit some kind of the ontogenetic niche shift are fish, insects and amphibians. A niche shift is thought to be determined genetically, while also being irreversible. Important aspect of the ONS is the fact, that individuals of different stages of a population utilize different kind of resources and habitats. The term was introduced in a 1984 paper by biologists Earl E. Werner and James F. Gilliam.

References

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  2. ↑ May, Robert (2007-09-28), Bock, Gregory R.; Goode, Jamie A. (eds.), "Levels of Organization in Ecological Systems", Novartis Foundation Symposium, Novartis Foundation Symposia, 213 (1 ed.), Wiley: 193–202, doi:10.1002/9780470515488.ch14, ISBN   978-0-471-97770-4, PMID   9653724 , retrieved 2024-12-13
  3. ↑ Hughes, A. Randall; Inouye, Brian D.; Johnson, Marc T. J.; Underwood, Nora; Vellend, Mark (2008). "Ecological consequences of genetic diversity". Ecology Letters. 11 (6): 609–623. Bibcode:2008EcolL..11..609H. doi:10.1111/j.1461-0248.2008.01179.x. ISSN   1461-0248. PMID   18400018.
  4. 1 2 Wadgymar, Susana M.; Sheth, Seema; Josephs, Emily; DeMarche, Megan; Anderson, Jill (2024-05-01). "Defining Fitness in Evolutionary Ecology". International Journal of Plant Sciences. 185 (3): 218–227. doi:10.1086/729360. ISSN   1058-5893. PMC  11257499. PMID   39035046.
  5. ↑ Comolli, Luis R. (2014-11-24). "Intra- and inter-species interactions in microbial communities". Frontiers in Microbiology. 5: 629. doi: 10.3389/fmicb.2014.00629 . ISSN   1664-302X. PMC   4241841 . PMID   25505455.
  6. ↑ Bell, G. (November 2007). "The evolution of trophic structure". Heredity. 99 (5): 494–505. doi:10.1038/sj.hdy.6801032. ISSN   1365-2540. PMID   17687253.
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  9. ↑ Richards, Zoe T.; Day, Jon C. (2018-05-08). "Biodiversity of the Great Barrier Reef—how adequately is it protected?". PeerJ. 6: e4747. doi: 10.7717/peerj.4747 . ISSN   2167-8359. PMC   5947040 . PMID   29761059.
  10. ↑ McBride, M A; Huston, A C (2002-09-19), Loreau, Michel; Naeem, Shahid; lnchausti, Pablo (eds.), "Evaluating the relative strengths of biotic versus abiotic controls on ecosystem processes", Biodiversity and Ecosystem Functioning, Oxford University PressOxford, pp. 47–60, doi:10.1093/oso/9780198515708.003.0005, ISBN   978-0-19-851570-8 , retrieved 2024-12-13
  11. ↑ "Tropical Climate Stability and Implications for the Distribution of Life", Effects of Past Global Change on Life, National Academies Press (US), 1995, retrieved 2024-12-13
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