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The Role of Ecological Selection in Forest Growth Ecological selection is a topic under heavy debate in current literature. Many people do not know exactly what ecological selection is, or just how critical it is to evolution. On top of this, scientists still argue on the exact identity of ecological selection, whether it is acting as resource competition, a cause of sexual selection (Wagner 2012), or as a driver of speciation. Nonetheless, ecological selection is a crucial form of natural selection that must be recognized. In this text, ecological selection will be examined solely as any selective force created by the surrounding environment, including biotic and abiotic factors, and ignoring any sexual selection. To explain ecological selection, forests, one of earth’s foremost resources, will be used as an example. During forest growth, tree seedlings in particular, are various and numerous, making them excellent experimental subjects. They are ecosystem pioneers, and different tree seedlings can often react to a number of members in their ecological community in completely different ways, thus providing a spectrum of ecological occupations (Marks 2007). On the other hand, adult trees can heavily impact their ecological communities, reversing the roles of ecological selection, so this aspect of their lives will be discussed as well (Barnes 1980). Resource competition is one of the most obvious, and important, factors of ecological selection. Features such as food, shelter, water, and nutrients are all competed for daily, and can influence how selection will work (McLoughlin 2010). Forests play a huge role in resource competition, because sometimes they act as competitors, and sometimes they are the actual resource being competed for. In the former case, when trees are competing, they are usually doing it while young and colonizing a habitat. In the end, space is ultimately the desired resource, because space inhabits soil, nutrients, and sunlight. As stated, trees are actively competing, and during forest succession, this competition is extremely difficult and critical to a tree’s future. A site of tree growth can be influenced by slope, rockiness, mineral content, climate, and available sunlight (Park, 2010). Space is initially available to everything, but seedlings that can most quickly inhabit the soil and take advantage of the available nutrients are usually most successful. Generally, one of the first factors to control which species grow best in the soil is the amount of sunlight. Soil and water themselves are both very important (For instance, a dry hardwood such as a white oak will not grow in a swamp), but sunlight is the initial decider in forest succession (Barnes 1980). Shade intolerant trees can immediately grow impressively. They need the sunlight that is offered by an open canopy found in a bare environment. Selection weeds out the seedlings that can not handle full sun, thus tall, straight trees will eventually grow and develop a full, lush canopy. However, these behaviors will soon be reversed. Seedlings that were once removed by ecological selection now become favored, because the shaded forest floor has become ideal for such shade tolerant species. This is a great example of how ecological selection can create niches for different species by performing the same function with different outcomes (Barnes 1980). On a broader scale, a study in Panama has shown what can happen in forests as a result of regionally varying environmental conditions. Whether it is by soil or any other resource, genetically similar trees vary vastly according to each locale, throughout the several environments examined. For example, some of the trees survived well in wet, rainy locations, while very closely related trees needed sunny, sandy areas to survive, and the same is said for certain pathogens and slope positions (Park 2010). These findings outline how environmental selection worked in the past, radiating similar trees into a niche to eventually diverge into separate species and subspecies. Continuing with the discussion of species diversity, in 2003 another study was performed in the Bolivian Amazon examining the relationship between a secondary forest structure and its amount of species diversity. The researchers ultimately found that older forests with larger stands and canopies had more diversity. Out of the 250 recorded species, 50% of those made up 87% of the total forest (Peña-Claros 2003). These findings were made possible by the measurements of available sunlight, and in the end, they reinforced the theory that increased environmental variation and increased ecological selection leads to more species diversity. This also displays how strong selection can lead to adaptations, thus forming ecological niches. These niches allow for less competition, conversely allowing greater diversity (Futuyama 2013). As mentioned before, elements of the soil are also an extremely influential selective factor in forest growth. Throughout time, every species of tree has evolved to grow under specific soil conditions, whether it is dependent on the pH levels, the mineral contents, or the drainage levels (Barnes 1980). Each of these is a vehicle for ecological selection to do its work in the course of evolution. However, ecological selection can be much more specific, not only working within species but within populations, even populations in the same region. For example, scientists in Quebec recently examined how tree seedlings react to different nitrate levels. What they found was that areas with higher nitrate levels contained plants that could much more efficiently metabolize nitrogen. Such plants could perform photosynthesis and respiration at a much faster rate than their nitrogen lacking peers, and also had longer root lengths on average, giving them an evolutionary advantage for their habitat. Nitrogen levels that are unexpectedly too high could harm some tree species, but these particular specimens created a niche for themselves, and could outcompete others around them (Marks 2007). All of the described examples outline how trees react to ecological selection. However, ecological selection involves the entire ecosystem, meaning that many more types of organisms can be involved. In turn, this means that trees are often influencing selection, along with other forces such as gene flow and mating, by being a means of habitat, either supportive of other species or possibly, when selecting against certain traits, being unsupportive. Consequently, those selected traits are eliminated from the population. In the instance of trees as a resource, there is a virtually universal influence because organisms frequently compete for them. Forests are a resource themselves, providing habitat, nourishment, and nutrient cycling, and together, these provisions ultimately present a source of ecological niches for other species. Many species need forest cover, while others don’t. Also, forests provide food for many organisms with specific dietary needs. As forest succession continues, more organisms become drawn to the site, and this will eventually create a food web and thus a forest community (Park 2010). A great example of forests as a selective force can be found in Central Africa. In 2012, Scientists went to various jungle-covered African nations to study different clades of Praomys misonnei, a forest rodent widely distributed throughout tropical Africa. The rodent displays four allopatric clades: one in Ghana and Benin, one in Central and east-Africa, one in Nigeria, and one in west-Central Africa. What the researchers found was that during the Pleistocene era, these clades evolved due to geographic separation via rivers and volcanoes. Today, all of the clades of misonnei have very different diets and lifestyles due to their evolutionary upbringing, so that when they are displaced in various forest refuges through gene flow (such as migration or displacement via cars and transported logs), or are forced to deal with secondary forest succession after logging or a wildfire, many do not cope well due to the force of ecological selection. Some forests contain predators unknown to the mice, and some do not provide adequate nutrition or forest cover. Thus, succession brought in unfamiliar mice, and they were quickly removed by selection, reinforcing their speciation (Nicolas 2012). Ultimately, ecological selection can be recognized for many of the evolutionary traits we see in all species. Darwin’s finches were distinguished by their beaks- a result of their environment. Giraffe neck length, insecticide-resistant insects, and even human traits such as skin and hair color can all be largely attributed to ecological selection, and determinedly it should be a subject worth further research. In conclusion, forests can provide a vast array of fascinating information, and with their growth comes the display of ecological selection in action. Soil, sunlight, mice, and trees themselves are all important members of an ecological community, and they can provide a view into how evolution is acting upon every aspect of a forest, all by the mechanism of ecological selection.

Brigner.15 (talk) 22:53, 17 November 2014 (UTC)

October 1 assignment:

https://en.wikipedia.org/wiki/Ecological_selection

Brigner.15 (talk) 16:08, 23 September 2014 (UTC)

I think this article could use quite a bit of editing. Some suggestions I have in mind are:

1) use more citations, obviously, and no original research.

2) Provide more circumstance for which it occurs. Ecological selection is huge component of natural selection, and I think it needs to be accentuated more in this article. Also I feel that the comparison to sexual selection is somewhat unnecessary, and it leads to more confusion about the issue.

3) Lastly, I feel that the structure of the article is insufficient. A paragraph providing more examples would be beneficial, as well as a history of experts and their studies.

Ecologists often study ecological selection when examining the abundance of individuals per population across regions, and what governs such abundances.[1]

Citation: McCoughlin, Phillip D.; Morris, Douglas W.; Fortin, Daniel; Vander Wal, Eric; Contasti, Adrienne L. (January 1, 2010). "Considering ecological dynamics in resource selection functions". Journal of Animal Ecology 79 (1): 4. doi:10.1111/j.1365-2656.2009.01613.x. Retrieved 23 September 2014.

Brigner.15 (talk) 13:24, 30 September 2014 (UTC)

Liberty Brigner

EEOB 3310

Tuesday, 8:00 A.M.

Futuyma, D. (March 18, 2013). The origin of species by means of ecological selection. Current Biology, 23, 6.)

In this article, Futuyama describes how in the past, ecological slection has been described in different ways, but all pointing to similar important mechanisms such as sympatric speciation, postmating selection, and most importantly, certain forms of reproductive isolation (such as varied breeding patterns or habitat). Futuyama then goes on to describe how reproductive isolation came to evolve, mostly through ecological terms.

This article is a great resource because Futuyama makes strong arguments regarding the importance of ecological selection, even going as far to say that “most speciation involves ecology in one way or another”. This article will help me tie together the connectivity of ecological factors like geography, climate, and breeding seasons with reproductiveness, ultimately pointing to natural selection and evolution as a result.

McLoughlin, P. D., Morris, D. W., Fortin, D., Vander, W. E., & Contasti, A. L. (January 	01, 2010). Considering ecological dynamics in resource selection functions. The 	Journal of Animal Ecology, 79, 1, 4-12. This article focuses on interactions among organisms, and how the abundance of these occurrences effects resource selection. Then, the writers go on to explain the resource selection function, which governs what organisms choose when eating, mating, or finding a home. Also, the article describes how competition and density-dependent habitat selection can effect mating, thus shaping a population’s genotypic makeup.

I believe that this article will be of use when studying ecological selection, because it focuses on natural resources in an environment, which are possibly the most important factor of ecologic selection.

Nanay, B. (January 01, 2010). Natural selection and the limitations of environmental 	resources. Studies in History and Philosophy of Biological and Biomedical 	Sciences, 41, 4, 418-9.

This article argues the assertion that cumulative selection explains adaptation when environmental resources are scarce It then goes on to tell how this limitation of natural resources is important in natural selection, and how this helps natural selection destroy certain, insufficient traits, and stabilizes other ones.

I think this paper will be useful because it highlights the relationship between natural resources and actual genetic traits. The idea that resources must be limited is interesting, and it will be good insight to provide in my own article.

Scheiner, S. M., Donohue, K., Dorn, L. A., Mazer, S. J., Wolfe, L. M., & Willis, J. (November 01, 2002). Reducing Environmental Bias When Measuring Natural 	Selection. Evolution, 56, 11, 2156-2167. This article points out the importance of phenotypic selection, and how it can often be biased by environmental variation, usually causing a false relationship between a certain trait and fitness. The article then goes on to describe how to analyze genotypic data, to either confirm or reject this relationship. The team studying this did so by performing an experiment involving three different plant species, grown in a controlled greenhouse, and estimating their strength of selection based on the correlation between genotypic and phenotypic data. This paper will be of importance for my Wikipedia project because it helps to show the ultimate relationship between phenotypic data and genotypic data, whether influenced or not. Phenotypes are often influenced solely by the environment, so tis will be helpful when informing readers how active and prominent ecological selection actually is, and how it truly effects the genetic makeup of a population.

Wagner, C. E., Harmon, L. J., & Seehausen, O. (January 01, 2012). Ecological 	opportunity and sexual selection together predict adaptive radiation. Nature, 487, 	7407, 366-9.

This article describes why some groups of species exhibit adaptive radiation in many places, while others don’t. The authors display how environmental factors, along with genetic traits, can influence diversification. The interactions of genotypic and phenotypic factors can help push species into many varied and diverse habitats. The scientists involved exhibited this theory with a case study in the African Great Lakes region.

I think this article is useful because it describes how environmental and genetic factors are tied together when natural selection is working in various environments. Instead of rejecting genotypic inheritance, or arguing that it is less important, it merely describes how it is tied together with phenotypic variance, and this will help give me an unbiased view when writing my Wikipedia article.