Niche construction

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Beavers hold a very specific biological niche in the ecosystem: constructing dams across river systems.

Niche construction is the process by which an organism alters its own (or another species) environment. These alterations can be a physical change to the organism’s environment or even encompass when an organism leaves one habitat for another. Although these alterations are often beneficial to the constructor they do not always increase chances of survival. The process of niche construction can be very broad but for an organism to be considered a niche constructor then the change must follow certain rules.[1][2] When determining if an organism is undergoing niche construction that organism must satisfy the following three criteria: 1) the organism must significantly modify environmental conditions, 2) these modifications must influence selection pressures on a recipient organism, & 3) There must be an evolutionary response in at least one recipient population caused by the environmental modification.[3]

Recently, some biologists have argued that niche construction is as important to evolution as natural selection.[3] They believe that not only does an environment select for changes in a species but a species also can cause changes in their environment through niche construction. This intricate back-and-forth creates a feedback relationship between natural selection and niche-construction: when organisms affect their environment, that change can then cause a shift in what traits are being naturally selected for.[4] The effect of niche construction is especially pronounced in situations where environmental alterations persist for several generations, introducing the evolutionary role of ecological inheritance. This theory, in conjunction with natural selection, shows that organisms inherit two legacies from their ancestors: genes and a modified environment. Together, these two evolutionary mechanisms determine a population's fitness and what adaptations those organisms develop in the continuation for their survival. A niche constructing organism may or may not be considered an ecosystem engineer. Ecosystem engineering is a more specific concept being precisely tied to structural changes brought about in the environment, while the former encompasses any kind of change.[5][6]

Examples[edit]

Leafcutter Ants fill a vital niche in the rainforest ecosystem

Organisms can achieve environmental modification in a number of ways. Organisms can directly alter their environments (i.e. corals making coral reefs), disrupt an already fluctuating variable in the environment (stop or encourage), or even leave an environment entirely.[7] Some examples of how species can undergo niche construction are as follows:

  • Earthworms: Through a process of modification, earthworms chemically alter the soil in which they live. This change in soil chemistry stimulates an increased fitness in earthworm populations. The subsequent chemical composition of soil produced by earthworm activity also benefits the growth of proximal species of plants and other biota present in the soil.[8]
  • Lemon Ants (Myrmelachista schumanni): This species of ants employs a specialized method of suppression that regulates the growth of certain trees. Lemon ants make their homes in the bodies of Duroia hirsuta, a species of tree found in the Amazonian rain forest of Peru. To ensure the prevalence of Duroia trees, Lemon ants employ self-derived quantities of formic acid (a chemical fairly common among species of ants) as a tenacious herbicide. The end result alters the composition of their forest habitat drastically by wiping out arboreal species ill-suited for colony habitation. When observed by humans, the subsequent altered ecologies perpetuated by these ants have been termed the Devil's Gardens.[9]
  • Beavers: In the construction of their dams, beavers drastically shape and alter the ecosystem in which they live. Deforestation, effects on soil structure, root structure, turbidity of water, allocation of water and the supply of water downstream are just a handful of exemplars defining beaver niche construction. Beavers express a clear example of the diverse effects perpetuated by the construction of a niche. In the mammalian kingdom beavers are one of the greatest proximal modifiers.
  • Diatoms in the Bay of Fundy, Canada, provide another example of an ecosystem engineer. Benthic diatoms living in estuarine sediments secrete carbohydrate exudates that bind the sand and stabilize the environment. The diatoms cause a physical state change in the properties of the sand that allows other organisms to colonize the area. The concept of ecosystem engineering brings new conceptual implications for the discipline of conservation biology.[7]
  • Pine Trees & Chaparrals: Chaparrals and pines have been found to express niche constructing behavior in response to the effects of forest fire. These trees and shrubs increase the frequency of fire by affecting the composition of the forest floor. They achieve this end through the dispersal of needles, cones, seeds and oils, essentially littering the forest floor. The benefit of this activity is compounded by an adaptation in these particular flora that has been selected for a resistance to fire. The evolutionary exchange (made between both niche construction and natural selection) allows the fire-resistant pine and chaparral to exploit the chemical change that occurs in soil after organic matter has been burned.[8]
  • Yeast: Saccharomyces cerevisiae yeasts create a novel environment out of fermenting fruit. This fermentation process in turn attracts fruit flies that they are closely associated with and utilize for transportation.
  • Humans: See subsection below.

Consequences for organisms[edit]

A Reed Warbler feeding its large, infant intruder.

As creatures move into new niches, they can have a significant effect on the world around them.[10]

An important consequence of niche construction is that it can affect the natural selection pressures put on the species doing the constructing. The common cuckoo bird is an excellent example of such a consequence. This species of bird parasitizes other birds by laying their eggs in the other species' nests. This had led to several adaptations among the cuckoos, one of which is a short incubation time for their eggs. The eggs need to hatch first so that the chick can push the other species' eggs out of the nest, ensuring it has no competition for the parents' attention. Another adaptation it has acquired is that the chick mimics the calls of multiple young chicks, so that the parents are bringing in food not just for one offspring, but a whole brood.[10]

A second consequence of niche construction is that it can be used to help explain how the modifications made by an individual can actually affect the evolutionary path of later generations.[7] This can mean that the evolution of other species using the same altered niche will also be affected. This would include organisms that associate directly with those performing the niche construction/modification (i.e. mutualisms).[11] Studies suggest the organisms undergoing niche construction can actually override external sources of selection to create new evolutionary pathways. These new paths can lead to unexpected outcomes (it should be noted that individuals cannot plan their own evolution).[7] For instance, populations evolving in response to the environment modified by their ancestors can exhibit any one of several effects: continuing to adapt and evolve in the same way, have no noticeable evolutionary response to selection for a number of generations or have an opposite and sudden response to this new modified selection.[1]

Humans[edit]

Niche Construction in Evolutionary Time.
Niche Construction in Evolutionary Time.[8]

Niche construction has many implications for the human sciences, more specifically human sociobiology, evolutionary psychology, and human behavioral ecology. Standard evolutionary theory only allows for cultural processes to affect genetic evolution by influencing the individual, and depends on the ability of that individual to survive and pass on its genes to the next generation. Cultural processes are viewed merely as an aspect of the human phenotype and are not believed to be consequential to human evolution. Cultural diversity is believed to reflect variation in the environments that different populations of humans evolved in, and nothing else. This theory overlooks the fact that humans can modify their selective environments through cultural activity, thus feeding back to affect selection.[1] "Cultural processes add a second knowledge inheritance system to the evolutionary process through which socially learned information is accrued, stored, and transmitted between individuals both within and between generations."[1]

With the addition of language to the human culture came an increased mental capacity. This allowed for human adaptation of the environment to be a learned process, unlike nonhuman species, whose adaptive process is instinctual. This resulted in the acceleration of environmental, behavioral and genetic modifications. As niche construction advocate Derek Bickerton writes, "We could construct our niches without having to wait on interminable rounds of feedback between genes and behavior."[12]

A theory on gene-culture coevolution calls for a more integrated relationship between genetic evolution and cultural processes than standard evolutionary theory. In this model, cultural activities are believed to affect the evolutionary process by modifying selection pressures. In other words, cultural change has the capacity to codirect its population's genetic evolution. Mathematical and conceptual models including investigations of language, handedness, the emergence of incest taboos, the coevolution of hereditary deafness and sign language, and sexual selection with a culturally transmitted mating preference demonstrate this theory. However, this theory is still dependent on standard evolutionary theory because it requires that cultural processes only affect genes directly, not allowing for any intermediate factors in the environment to interact with these processes at an evolutionary level. This theory exists on a dual inheritance system consisting solely of genes and cultural activity. "The dual inheritance system is a way to include interactions between nature and nurture in a tractable system."[1] In most cases this theory works smoothly, however there are instances where cultural activities create changes in the abiotic environment that then affect selection pressures.[1]

The speed at which humans are able to construct niches modifies the selection pressures and either genetic evolution or further niche construction can result.[13] An example of genetic evolution through niche construction with the inclusion of an abiotic factor: yam cultivators in West Africa cut clearings in forests to grow crops, but resulted in much standing water which attracted mosquitoes and increased the rate of malaria. This caused a modification to the selection pressure for the sickle-cell allele that protects against malaria. Evolutionary change is thus furthered. Example of further niche construction: Humans change the environment through pollution. The effects of pollution are alleviated by the innovation and use of a new technology. This cultural response to a constructed niche allows for a change in environment and a lack of change in genetics. Only if a new technology is not created or effective will evolutionary change occur. Humans are able to sustain adaptiveness by responding to ancestral niche construction through further cultural niche construction.[13]

The addition of niche construction to the study of evolutionary processes forces scientists to accept that cultural activity is not the reason that humans are able to modify their environments, but is simply their primary means of doing the same thing that other species do. The fact that a large number of cultural processes are learned rather than genetically encoded into the individual, makes human culture an incredibly powerful method of niche construction. "Most of the time, cultural processes can be regarded as a shortcut to acquiring adaptive information, as individuals rapidly learn, or are shown, what to eat, where to live, or how to avoid danger by doing what other more knowledgeable individuals do."[1]

The development of sickle cells is believed to have been partially the result of the increased mosquito/malaria rates brought about by standing water from yam cultivation in Africa.

Current status[edit]

Niche construction remains controversial.[2] Skeptics assert that aspects of niche construction theory (NCT) have been investigated for many decades before the term originated and the same predictions can be derived from standard evolutionary theory (modern synthesis).[14] They also argue that niche construction is not a distinct evolutionary process. According to a critical review in 2014, Scott-Phillips et al wrote:

NCT argues that niche construction is a distinct evolutionary process, potentially of equal importance to natural selection. The skeptics dispute this. For them, evolutionary processes are processes that change gene frequencies, of which they identify four (natural selection, genetic drift, mutation, migration [ie. gene flow])... They do not see how niche construction either generates or sorts genetic variation independently of these other processes, or how it changes gene frequencies in any other way. In contrast, NCT adopts a broader notion of an evolutionary process, one that it shares with some other evolutionary biologists. Although the advocate agrees that there is a useful distinction to be made between processes that modify gene frequencies directly, and factors that play different roles in evolution... The skeptics probably represent the majority position: evolutionary processes are those that change gene frequencies. Advocates of NCT, in contrast, are part of a sizable minority of evolutionary biologists that conceive of evolutionary processes more broadly, as anything that systematically biases the direction or rate of evolution, a criterion that they (but not the skeptics) feel niche construction meets.[14]

Proponents of the NCT call for an extended evolutionary synthesis.[15][16] Laubichler and Jürgen, 2015 argue that niche construction theory offers the study of a broader range of evolutionary phenomena "the notion of expanded and multiple inheritance systems (from genomic to ecological, social and cultural)."[16]

In a 2015 review Smith concluded: "Explanations [for domestication of plants and animals] based on diet breadth modeling are found to have a number of conceptual, theoretical, and methodological flaws; approaches based on niche construction theory are far better supported by the available evidence in the two regions considered [eastern North America and the Neotropics]".[17]

See also[edit]

References[edit]

  1. ^ a b c d e f g Odling Smee, John; Laland, Kevin; Feldman, Marcus (2003). Niche Construction: The Neglected Process in Evolution. Princeton: Princeton University Press. 
  2. ^ a b Pocheville, Arnaud (2010). "What Niche Construction is (not).". La Niche Ecologique: Concepts, Modèles, Applications. Paris: Ecole Normale Supérieure. pp. 39–124. 
  3. ^ a b Yeoman, Carl J. (2011). "Towards an evolutionary model of animal-associated microbiomes". Entropy: 570–594. 
  4. ^ Levins, Richard; Lewontin, Richard C. (1985). The Dialectical Biologist. Cambridge, MA: Harvard University Press. 
  5. ^ =Lewontin1983 Lewontin, Richard C. (1983). "Gene, Organism and Environment.". In Bendall, D. S. Evolution from Molecules to Men. Cambridge: Cambridge University Press. 
  6. ^ Odling-Smee, F. J. (1988). "Niche-Constructing Phenotypes.". In Plotkin, H. C. The Role of Behavior in Evolution. Cambridge (MA): MIT Press. pp. 73–132. 
  7. ^ a b c d Boogert, N. J.; Paterson, D. M.; Laland, K. N. (2006). "The Implications of Niche Construction and Ecosystem Engineering for Conservation Biology" (PDF). BioScience. 56 (7): 570–8. ISSN 0006-3568. doi:10.1641/0006-3568(2006)56[570:TIONCA]2.0.CO;2. 
  8. ^ a b c Odling-Smee, John F. (2009). "Niche Construction in Evolution, Ecosystems and Developmental Biology". Mapping the Future of Biology, 69-91. ISBN 978-1-4020-9635-8.
  9. ^ Reece, Urry, Cain, Wasserman, Minorsky & Jackson (2011). Campbell Biology. ISBN 978-0-321-55823-7.
  10. ^ a b Odling-Smee, John F. (2003). Niche Construction: The Neglected Process in Evolution. Princeton, New Jesey: Princeton University Press. pp. 10–11. ISBN 978-0-691-04437-8. 
  11. ^ *Odling-Smee, J (2013). "Niche construction theory: a practical guide for ecologists". The Quarterly Review of Biology. 88. 
  12. ^ Bickerton, Derek (2009). Adam's Tongue. New York, New York: Hill and Wang. 
  13. ^ a b Laland, Kevin N.; Kendal, Brown (2007). "The Niche Construction Perspective". Journal of Evolutionary Psychology: 51–66. 
  14. ^ a b Scott-Phillips, T. C.; Laland, K. N.; Shuker, D. M.; Dickins, T. E.; West, S. A. (2014). "The Niche Construction Perspective: A Critical Appraisal". Evolution. 68: 1231–1243. PMC 4261998Freely accessible. PMID 24325256. doi:10.1111/evo.12332. 
  15. ^ John Odling-Smee et al. "The extended evolutionary synthesis: its structure, assumptions and predictions". Proceedings of the Royal Society B: Biological Sciences, August 2015.
  16. ^ a b Laubichler, Manfred D; Renn, Jürgen (2015). "Extended evolution: A Conceptual Framework for Integrating Regulatory Networks and Niche Construction". Journal of Experimental Zoology Part B: Molecular and Developmental Evolution. 324: 565–577. doi:10.1002/jez.b.22631. 
  17. ^ "A Comparison of Niche Construction Theory and Diet Breadth Models as Explanatory Frameworks for the Initial Domestication of Plants and Animals". Journal of Archaeological Research. 23: 215–262. doi:10.1007/s10814-015-9081-4. 

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Further reading[edit]

External links[edit]

  1. ^ Kylafis (2008). "Ecological and evolutionary consequences of niche construction for its agent". Ecology Letters. 11: 1072–1081. doi:10.1111/j.1461-0248.2008.01220.x. 
  2. ^ Day (2003). "Rethinking Adaptation: the niche construction perspective". Perspectives in Biology and Medicine. 46: 80–95. PMID 12582272. doi:10.1353/pbm.2003.0003. 
  3. ^ Erwin., D (2008). "Macroevolution of ecosystem engineering, niche construction and diversity". Cell Press. 
  4. ^ Buser, R (2014). "Niche construction initiates the evolution of mutualistic interactions". Ecology Letters. 
  5. ^ Scott-Phillips, T (2013). "The Niche Construction Perspective: A Critical Appraisal". The Society for the Study of Evolution. 68: 1231–1243. PMC 4261998Freely accessible. PMID 24325256. doi:10.1111/evo.12332.