What Is Niche Construction?
Niche construction is a term used to refer to the process through which a particular organism modifies its environment. These modifications can either be a physical change to the environment or the changes that accrue when an organism abandons its habitat. Such alternations include the creation of shade and the construction of nests and burrows. Evolution through niche construction can occur if the modifications affect natural selection pressures. Anthropologists and biologists have long acknowledged that animals extensively alter their habitats and that this process is applied to the extreme by human beings. The term itself was coined in 1988 by John Odling-Smee, an Oxford biologist who sought to have the occurrence included as an evolutionary process.
Description
In modifying their surroundings, organisms change the selection pressures acting on both the present and future generations of the particular organism. The alterations pose a range of benefits for the constructor although the chances of survival may fail to increase. A process will be considered niche construction if it satisfies three criteria. One, the organism must substantially alter environmental habitats. Secondly, the modifications must exert influence on the selection pressures on a particular recipient organism. Thirdly, an evolutionary response should also exist in at least one recipient triggered by the environmental modification. A section of biologists has recently argued that the process is as significant to evolution as natural selection proposing that when an organism alters its environment, that modification causes a shift in the characters being looked for natural selection. The repercussions of niche construction are especially prominent in situations where environmental modifications persist for some generations. This situation is called ecological inheritance where organisms not only inherit genes from their ancestors but a modified environment as well. A niche constructor may or may not qualify to be an ecosystem engineer.
Niche Construction By Beavers
Beavers are commonly recognized as ecosystem engineers, and they fascinate people with their construction of dams, canals, and lodges. The animal is a semi-aquatic rodent and the second-largest of the world's rodents. The rodent's presence is majorly restricted in North America. Beavers construct dams on streams and rivers after which they erect their houses called lodges in the resulting pond. Beavers further create canals to float those building materials that are challenging to transport over land. Beavers first station vertical poles then place branches horizontally in a crisscross manner. The gaps between the branches are filled with mud and weeds till the dam impounds adequate water to surround the lodge. Beaver dams are constructed as a protection against such predators like bears, coyotes, and wolves and to enable the easy access to food in winter. Beavers are known as prolific builders, and they work during the night. The animals may build a series of dams throughout a river. In the process of constructing their dams, beavers remove pollutants and sediments in water bodies. The animals, however, facilitate deforestation and affect root and soil structure and the allocation of water.
Other Examples Of Niche Constructors
Lemon ants represent another curious case of niche construction. These species establish its home in the bodies of the Amazonian Duroia hirsuta trees. These trees are particularly found in Peru. The ants then proceed to kill surrounding trees using formic acid to preserve Duroia trees. The ants are the only insects known to employ formic acid as an herbicide. The ants can live in large clearings dubbed devil's gardens whose bio-diversity is limited in comparison to the surrounding area. The activities of the ants thus modify the forest ecosystem. Earthworms are another example of niche constructors. The creatures inhabit the soil, and as they move they force air through the tunnels, they create. This activity mixes and aerates the soil and enables the mineralization of nutrients and their subsequent uptake by vegetation. Some earthworm species move to the surface for grazing purposes since the organic matter there is found in richer, and in doing so, they mix the surface soil with the mineral soil. This mixture is highly fertile, and farmers rejoice in the presence of earthworms. The actions of earthworms further convert large chunks of organic matter to rich humus. The creatures further affect the soil's chemical composition as their casts contain minerals such as nitrogen, potassium, and phosphates. This shift in soil chemistry facilitates an increased fitness in the organism's population. The new chemical soil structure brought about by the creature's actions is also beneficial to the growth of the plants' proximal species.
Effects On Organisms
Organisms can exert a substantial effect on the surrounding areas. Niche construction can influence the natural selection pressures exerted on the niche constructor. One good example of this scenario is the common cuckoo bird. These birds have learned to parasitize other birds by laying its eggs in the other species' nests. The bird has adapted to this activity by having a short incubation time for its eggs. It is necessary for the eggs to hatch quickly for the chick to push the eggs belonging to the other species out and thus eliminate competition for the parents' attention. The chick further mimics the call of several young chicks so that the parents return with food enough for a whole brood. Niche construction can also be employed to help describe how the alterations implemented by a single individual can influence the evolutionary path of subsequent generations. This situation can also mean that other species' evolution in the context of the modified niche will also be influenced. The process would also affect those organisms that directly interact with the niche constructors that is mutualism. Studies have revealed that the creatures undergoing niche constructions can override the external selection sources to create other evolutionary pathways. These paths can result in unintended consequences. Populations which inherit altered habitats can either continue to evolve or adapt in a similar way to their ancestors, lack of any identifiable evolutionary response to natural selection for several generations, or exhibit a sudden response to the new altered selection.
Current Status
The concept of niche construction is still controversial. Skeptics argue that the niche construction theory's (NCT) aspects have been researched for numerous decades before the emergence of the term and that the same predictions can be arrived at using the standard evolutionary theory. The skeptics further assert that the occurrence is not a distinct evolutionary theory. Supporters of the NCT propose for an extended evolutionary synthesis. Laubichler and Jürgen, 2015 assert that the NCT provides for the study of a more extensive range of evolutionary phenomena.
