Which of the following provides the most accurate example of primary succession
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Primary succession
Primary succession is an ecological succession where a newly formed area is inhabited for the first time by a group of species or a community. This previously uninhabited, barren area is usually lacking topsoil and organic matter. The species that first established an uninhabited area is referred to as the pioneer species and the dominating community is called the pioneer community. Soon, a wider range of plants and animals will occupy the area until a climax community is established. If disturbed or interfered with by a disruptive external or internal factor, the species inhabiting the area could subsequently be replaced by a new ecological succession, called secondary succession. Since the area has already been inhabited during a primary succession, the secondary succession could occur rather faster, i.e. in decades or hundreds of years as opposed to a primary succession that could take thousands, even millions of years. EtymologyThe word succession from an ecological viewpoint was first used by the French naturalist, Adolphe Dureau de la Malle. The word is used to refer to the vegetation development after forest clear-felling. Successions in the EcosystemEcological succession is the progressive succession of a group of species or a community over a given period, e.g. spanning over decades or millions of years. Usually, there is one dominant group of life forms that successfully established a stable climax community over a particular area. Primary and secondary successionsIn this diagram, the process begins with a bare rock formed from volcanic eruptions or from retreating glaciers. The next stage is the pioneer species (lichens and moss) growing on the rock. The death and, subsequently, the decomposition of these species contribute to soil formation. The next group of plant colonizers is grasses and herbaceous plants. They are next replaced by shrubs and bushes, then by trees. As the diversity of plant species improves, the animals occupying the area also become diverse. However, since competition for sunlight, space, and nutrients is increased, those that are better adapted and more tolerant survive and thrive, e.g. ‘shade-tolerant trees”. Ecological succession may be primary or secondary. Both types are characterized by a progression of prevailing communities of species in a particular habitat. They differ in terms of the ecological history and origin of the habitat. For instance, a primary succession occurs when a group of species or a community colonize a barren, newly formed habitat. An example of primary succession is the establishment of plant or animal communities in an area where no soil initially exists, such as bare rocks formed from a lava flow. Other examples are the colonization of a barren area following a severe landslide or recently exposed land from retreating glaciers. Another is the occupying of harsh habitats, such as sand dunes. The extremely hot temperature of sand dunes makes them available for habitation to only a few highly specialized plants and animals. Secondary succession occurs when a previously occupied area is colonized by a new dominating group of species or communities. In secondary succession, the new inhabitants replace the previous communities over a habitat that had been exposed to a particular ecological disturbance. The disturbance may be an external or an internal factor. An example of secondary succession is the recolonization of an area damaged by fire. Another difference between primary and secondary successions is the nature of the habitat. In primary succession, living things colonize a barren land, which means it lacks topsoil. Conversely, in secondary succession, living things will be re-colonizing a previously inhabited area and therefore the area would have topsoil containing organic matter from the previous inhabitants. Primary succession takes a longer period of time to be established and completed, i.e. a thousand or more years. On the contrary, the secondary succession often occurs relatively faster, requiring only a shorter period of time, like a decade or a hundred years. This is because an area that has just been newly formed would be initially unfavorable for most life forms. The newly formed land, for instance, would lack soil but would be comprised of bare rocks. This is the starting stage of primary succession. A series of physicochemical changes have to occur until such time that they become more conducive to life. The species that are able to inhabit a newly formed or formerly uninhabited land are called pioneer species and the community that has successfully established and dominated is called the pioneer community. A community refers to an ecological unit comprised of a group of organisms or a population of different species that occupy a given area. A community may refer to a small population inhabiting small areas (as in a pond) or communities in large geographical areas, which define “biome“. The settling of a pioneer community marks the start of the colonizing phase of primary succession. Examples of pioneer species are lichens, algae, and fungi. These species are more tolerant and eventually contribute to the formation of the soil by breaking down rocks into smaller particles. They also provide organic matter to the area. Eventually, the area is laden with thin soil and thus becomes favorable for the growth of higher forms of species. The next species that colonize and dominate the area are referred to as intermediate species. Examples are grasses and shrubs that can thrive in thin soils. As the habitat improves, a wider range of vegetation and small animals can occupy the area. The final stage is the establishment of a climax community, i.e. a community comprised of even higher forms of life, e.g. shade-tolerant trees and sturdier tall trees that attract larger and higher forms of animals. If the habitat is exposed to a disturbance that can bring disruption to its inhabitants, the second succession occurs. Since the area is already inhabited by plants and animals, the area after the disturbance would likely remain habitable and thus will be easier and available for re-colonization.
A third type, called cyclic succession, is a type of succession wherein a group of species replaces a previously dominant species over time without a large-scale disturbance. Watch this vid on ecological successions:
ImportanceThe primary succession is important in pioneering the area to create conditions favorable for the growth of other forms of plants and animals. It paves the way for the next successions as the previously thriving organisms could become an essential component of the soil. Since the pioneer species are more tolerant of a harsh environment, they could put into use the available nutrients and convert them into another form for use by other life forms. Thus, it is not surprising that lichens serve as a pioneer community as they are one of the most fundamental and efficient symbioses in an ecosystem. Answer the quiz below to check what you have learned so far about primary succession. Further Reading
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© Biology Online. Content provided and moderated by Biology Online Editors Which is an example of primary succession?Primary succession happens when a new patch of land is created or exposed for the first time. This can happen, for example, when lava cools and creates new rocks, or when a glacier retreats and exposes rocks without any soil. During primary succession, organisms must start from scratch.
Which is an example of primary succession quizlet?Which of the following is an example of primary succession? Plant development on a layer of rock deposits.
What is correct about primary succession?Primary succession - Succession where a newly formed area is colonised for the first time by a species or living organisms. Such areas would have never been previously inhabited i.e it is barren and lacks fertile soil. For example, newly cooled lava, newly created pond reservoir, etc.
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