User:Mhay.103/sandbox

Topic: Bak-Sneppen Model

Meester, Ronald (11/2012). "Rigorous Self-organised Criticality in the Modified Bak-Sneppen Model". Journal of statistical physics (0022-4715), 149 (5), p. 964.

Veerman, J. J. P. (2014). "On Rank Driven Dynamical Systems". Journal of statistical physics (0022-4715), 156 (3), p. 455.

Machta, J. (11/2001). "Parallel dynamics and computational complexity of the Bak–Sneppen model". Physica A (0378-4371), 300 (1-2), p. 245.

Meester, R (2003). "Limit behavior of the Bak-Sneppen evolution model". The Annals of probability (0091-1798), 31 (4), p. 1986.

Schlemm, Eckhard (2012). "Asymptotic Fitness Distribution in the Bak–Sneppen Model of Biological Evolution with Four Species". Journal of statistical physics (0022-4715), 148 (2), p. 191.

Assignment due OCT.1: Talk page suggestions: [1] First, I believe a few examples of the application of the model should be added. This can include more current variations, and further application of the model past the field of evolutionary biology.

[2] Secondly, I believe the general description of the model is very ambiguous and it is nearly impossible to determine what the model is. This section could be re-tooled in order to better explain how exactly it is implemented to describe evolutionary processes between species.

[3] Thirdly, math involved in determining the stationary fitness distribution could be shown. This is the basis of modern study of the Bak-Sneppen Model, there are a few new and competing theories for determining this equilibrium. Adding these would just generally expand the information about Bak-Sneppen Model and further complete the article.

Page Contributions and citation: These "long-run" events are referred to as avalanches, and the model proceeds through these avalanches until it reaches a state of relative stability where all species' fitness are above a certain threshold.[2]

^ Wei, Li; Yang, Luo; YuanFang, Wang & AiPing, Cai. "A mean-field Bak-Sneppen model with varying interaction strength". Chinese Science Bulletin, 2011, p. 3639.

Link to page: https://en.wikipedia.org/wiki/Bak%E2%80%93Sneppen_model

ASSIGNMENT DUE BY END OF MONDAY, NOVEMBER 17:

[1] EDITS TO EXISTING WIKI ARTICLE: ARTICLE: Mating (talk section)

MY EDITS: (Are also in the talk pages, because it is a suggestion to add a completely new section.)

Mating Calls:

Discriminatory mate choice based on many different calling behaviors and characteristics have been studied, including call rate, call duration, duty cycle, and pulse rate (Pröhl, 2003). The relative importance of these calls varies widely among studied organisms. Explaining the diversity of these calls is a main focus of current scientific experimentation in order to determine the role of calls in sexual selection.

Factors Affecting Diversity:

Fitness Benefit:

For field crickets, differing chirp rates are postulated to be indicative of nutritional intake in the signaler. There is selection done by the females on the males for both calling songs and courtship songs. The females of this species of field crickets prefer both male crickets with higher chirp rates and longer chirp rates. The trait of higher chirp frequency has been shown to be dependent on nutritional intake, while the duration of chirps is independent of nutritional intake (Wagner, Reiser, 1999).

Environment:

Mating calls are also affected by many different environmental factors. Marsh frogs in Bulgaria were shown to have a very strong correlation between the dominant frequency in their calls and various environmental factors (Lukanov, Tzankov, Nikolay, Simeonovska-Nikolova, 2014). Male calls in field cricket populations were also shown to have strong environmental influences. Seasonality had an effect on the time at which mating calls were proliferated in these species. The effect of seasons on the mating call was not limited to timing, but the length of calls was also affected (Velez, Brockmann, 2006).

Predator-Prey Relationship:

The use of calls undoubtedly attracts not only prospective reproductive interactions, but also leaves organisms open to dangerous situations. Aposematism refers to warning coloration that informs predators of some inherent, dangerous quality in the prey. Experiments have shown that frogs that exhibit aposematism, show a marked increase in the diversity of mating calls versus frogs lacking this quality. This protection of warning coloration allowed the organisms to proliferate calling signatures more freely, because of relaxed selection against them (Santos, Baquero, Barrio-Amoros, Coloma, Erdtmann, Lima, Cannatella, 2014; Halfwerk, 2014).

Sources:

1] Pröhl, H. (2003), Variation in Male Calling Behaviour and Relation to Male Mating Success in the Strawberry Poison Frog (Dendrobates pumilio). Ethology, 109: 273–290. 2] William E. Wagner Jr., Michael G. Reiser (1999), The importance of calling song and courtship song in female mate choice in the variable field cricket. Animal Behaviour vol. 59, Issue 6, June 2000, pgs. 1219-1226. 3] Lukanov, Simeon P., Tzankov, Nikolay D., Simeonovska-Nikolova, Daniela M. (2014) Effects of Environmental Factors on Mating Call Characteristics of the Marsh Frog Pelophylax ridibundus (Pallas, 1771) (Amphibia: Ranidae) in Bulgaria. Acta Zooligica Bulgarica Volume: 66. Issue: 2. June, 2014. pgs: 209-216 4] Vélez, Manuel J.; Brockmann, H. Jane. (2006), Seasonal variation in selection on male calling song in the field cricket, Gryllus rubens. Animal Behaviour vol. 72 issue 2 August, 2006. p. 439-448 5] Santos, Juan C; Baquero, Margarita; Barrio-Amoros, Cesar; Coloma, Luis A; Erdtmann, Luciana K; Lima, Albertina P; Cannatella, David C. (2014), Aposematism increases acoustic diversification and speciation in poison frogs. Proceedings. Biological sciences / The Royal Society, volume:281, issue:1796. 6] Halfwerk, Wouter (2014). Risks of multimodal signaling: bat predators attend to dynamic motion in frog sexual displays. Journal of experimental biology (0022-0949), 217, p. 3038.

[2] MY FINAL DRAFT STARTS HERE:

Vocalization discrimination is a term referring to the general choice or selection based on varying aspects of calls and songs between organisms. This includes both familiarity discrimination and mating calls, which among animals on Earth are quite widespread and documented as drivers of sexual selection via female choice and male-male competition. Discriminatory mate choice based on many different calling behaviors and characteristics have been studied, including call rate, call duration, duty cycle, and pulse rate (Pröhl, 2003). The relative importance of these calls varies widely among studied organisms. This may be due to the calls being indicative of different traits conveying fitness to the female between different species that both exhibit mating call behavior. One hypothesis to be explored is: male-male competition drives variation in these secondary sexual characteristics, and female choice is another level of selection that is less effective on the actual genetic diversity of the population. Another consideration in explaining the diversity of calls and discrimination between them is the predator-prey relationship. The use of calls undoubtedly attracts not only prospective reproductive interactions, but also unwanted or predator interactions. Considerations to all the possible interactions must be taken when drawing conclusions about the causes of variation or diversification in vocalization behaviors. For some organisms, the variation in mating calls is the result of varying body size or some other physical quality in males. The postulation is that males with larger body sizes are generally more fit, and a certain aspect of their call conveys this to the prospective females. This phenomenon is observed for some species, but does not apply to a large portion of others. For example, cricket calls have often been deduced to convey body size to females, but more recent and advanced studies suggest that there is no correlation between mating call traits and body size (Ferreira, Ferguson, 2002). This could imply that these specific calls are indicative of another trait that conveys fitness characteristics to the female. These studies continue on to say that mating call trait differences were not significant enough to be acted on by sexual selection. From here it is possible to deduce that the very act of calling is enough to signal females, but that competition between males for female resources are not fierce enough for sexual selection to impact reproduction rates. For field crickets, differing chirp rates are postulated to be indicative of nutritional intake in the signaler. There is selection done by the females on the males for both calling songs and courtship songs. The females of this species of field crickets prefer both male crickets with higher chirp rates and longer chirp rates. The trait of higher chirp frequency has been shown to be dependent on nutritional intake, while the duration of chirps is independent of nutritional intake (Wagner, Reiser, 1999). This work is further evidence of a preference in females that does not actually convey a fitness advantage (duration of chirps). The complexity of this system is apparent, and deserves thorough investigation. The simple explanation of varying calls being indicative of varying fitness levels in males is not supported. One possibility that has been explored to explain the diversification of mating calls has to do with the trade-off between signaling for mates and becoming more visible for predators. The phenomenon known as aposematism is one hypothesis used to explain the increase diversity of mating calls among frog populations (Santos, Baquero, Barrio-Amoros, Coloma, Erdtmann, Lima, Cannatella, 2014; Halfwerk, Dixon, Ottens, Taylor, Ryan, Page, Jones, 2014). Aposematism is most commonly used to describe warning coloration used to inform predators of some inherent, dangerous quality in the prey (Willink, Garcia-Rodriguez, Bolanos, Pröhl, 2014; Harlin, Harlin, 2003). Organisms that exhibit aposematism were shown to proliferate many more diverse calls and songs relative to organisms that lack warning signs for predators. This is evidence of yet another level of selection acting on mating call diversity. Mating calls are also affected by many different environmental factors. Marsh frogs in Bulgaria were shown to have a very strong correlation between the dominant frequency in their calls and various environmental factors (Lukanov, Tzankov, Nikolay, Simeonovska-Nikolova, 2014). Male calls in field cricket populations were also shown to have strong environmental influences. Seasonality had an effect on the time at which mating calls were proliferated in these species. The effect of seasons on the mating call was not limited to timing, but the length of calls was also affected (Velez, Brockmann, 2006). This is evidence that genetic differences between mating calls are not the only factors affecting the eventual selection of males that reproduce. The system of mating calls now has a much more complicated picture, because in order for female choice to have a real effect on the gene pool of the population, the traits being selected for must have a genetic backbone or cause. If the environment can also affect mating call traits, this opens the door for questioning the directionality of the sexual selection. Logic leads one to infer that directional stabilization would be present in these systems, because in each generation the females are choosing the ‘best’ male calls. This would, in theory push the average calls of the population toward whatever trait the females are selecting for. The introduction of environmental factors that influence these calls complicates this system and makes the link between call traits and genetic markers much less direct. Directional stabilization as an explanation of the true workings of sexual selection via calling traits is thus unlikely for many systems. Further support for this point comes from studies of the Strawberry Poison Frog, which uses mating calls extensively. From one study, it was shown that male endurance rivalry is a more correlated cause of variation in offspring production than female choice (Pröhl, 2003). From this field test, the scientists deduced that far greater diversity in calling characteristics was due to the age of the male, and over time in their tests, the calling rates of the males as a whole decreased (even though females prefer higher calling rates). From one generation to the next, males did continue to increase their mating success. The combination of these may show that mating calls alone are not always a comprehensive explanation of sexual selection via female choice. The alternative explanation that has been observed through research is stabilizing selection amongst mating calls. This pattern is observed when from one generation to the next, female frogs chose mates with mating calls populated around a certain mean in mating call trait. The frogs that were above or below the mean were chosen less often. Stabilizing selection has been observed when the females are discriminating based on dominant frequency or fine temporal properties such as pulse rate (Gerhardt, 1994; Friedl, 2006). The evidence of stabilizing selection in frogs may be indicative of alternate secondary sexual characteristics acting on the system. Alternatively, the directional selection from these populations may have run their course. Meaning that initially there was strong directional selection for a certain desirable call trait, but as the species moved through evolutionary time, the directionality of the selection leveled off to produce the contemporary results of stabilizing selection. The aforementioned complications to sexual selection based on vocalization discrimination are congruent with modern analysis of frog populations; that vocalization behavior is not highly stereotyped, but rather quite variable and subject to many different levels of selection (Baugh, Ryan, 2009). Individuals also use vocalization discrimination to distinguish familiar individuals from outsiders. One species of bat has been observed preferentially associating with bats from a similar cave or population subset (Boughman, Wilkinson, 1998). Birds also exhibit this behavior, and information used about familiarity can help individuals to normalize behaviors. This normalization of behavior leads to an increase in overall fitness (Warrington, McDonald, Rollins, Griffith, 2014). This evidence supports the idea that vocalization discrimination is widely used by organisms for a variety of reasons. Vocalization behavior variation is so widespread, it may be assumed that these processes evolved separately in animal species many times throughout evolutionary history. In other words, there is no specific point in evolutionary time that organisms began using vocalizations to signal and attract one another. Instead, the behavior most likely was acquired later by organisms, and once the behavior exhibited a greater fitness payoff, evolution proceeded to fix the behavior within some animal species. Vocalization discrimination is a phenomenon found all throughout the ecological world. Some organisms have this behavior ingrained into their mating routines, and this has created a situation where stabilizing or directional selection can occur to explain variation, depending on the species. It has a huge effect on the female choice aspect of sexual selection and therefore is an important part of our understanding of sexual selection pressures. Vocalization discrimination is also used in a non-sexual context by bats and birds to distinguish familiarity and help normalize behavior. This use of vocalization discrimination can increase the overall fitness of populations and can solidify the ecological niche of an organism in the system it participates in. Overall, continued research on vocalization discrimination is needed to further flesh out the role and importance it plays in natural selection.

-- Literature Cited -- Pröhl, H. (2003), Variation in Male Calling Behaviour and Relation to Male Mating Success in the Strawberry Poison Frog (Dendrobates pumilio). Ethology, 109: 273–290. Ferreira, M. and Ferguson, J. W. H. (2002), Geographic variation in the calling song of the field cricket Gryllus bimaculatus (Orthoptera: Gryllidae) and its relevance to mate recognition and mate choice. Journal of Zoology, 257: 163–170. William E. Wagner Jr., Michael G. Reiser (1999), The importance of calling song and courtship song in female mate choice in the variable field cricket. Animal Behaviour vol. 59, Issue 6, June 2000, pgs. 1219-1226. Boughman, Janette Wenrick and Wilkinson, Gerald S. (1998), Greater spear-nosed bats discriminate group mates by vocalizations. Animal Behaviour vol. 55 issue 6 June, 1998. p. 1717-1732 Miyako H. Warrington, Paul G. McDonald, Lee Ann Rollins, Simon C. Griffith (2014) All signals are not equal: acoustic signaling of individuality, sex and breeding status in a cooperative breeder. Animal Behaviour vol. 93, july 2014, pgs 249-260 Lukanov, Simeon P., Tzankov, Nikolay D., Simeonovska-Nikolova, Daniela M. (2014) Effects of Environmental Factors on Mating Call Characteristics of the Marsh Frog Pelophylax ridibundus (Pallas, 1771) (Amphibia: Ranidae) in Bulgaria. Acta Zooligica Bulgarica Volume: 66. Issue: 2. June, 2014. pgs: 209-216 Gerhardt, H. (1994). The Evolution of Vocalization in Frogs and Toads. Annual Review Of Ecology & Systematics, 25: pgs. 293-324. Santos, Juan C; Baquero, Margarita; Barrio-Amoros, Cesar; Coloma, Luis A; Erdtmann, Luciana K; Lima, Albertina P; Cannatella, David C. (2014), Aposematism increases acoustic diversification and speciation in poison frogs. Proceedings. Biological sciences / The Royal Society, volume:281, issue:1796.

Willink, B., García-Rodríguez, A., Bolaños, F. and Pröhl, H. (2014), The interplay between multiple predators and prey colour divergence. Biological Journal of the Linnean Society, 113: 580–589.

Halfwerk, Wouter (2014). Risks of multimodal signaling: bat predators attend to dynamic motion in frog sexual displays. Journal of experimental biology (0022-0949), 217, p. 3038.

Harlin, C., Harlin, M.(2003), Towards a historization of aposematism. Evolutionary Ecology vol. 17 issue 2 pgs.197-212

Friedl, T. W.P. (2006), Individual Male Calling Pattern and Male Mating Success in the European Treefrog (Hyla arborea): Is there Evidence for Directional or Stabilizing Selection on Male Calling Behaviour?. Ethology, 112: 116–126

Baugh, Alexander T.; Ryan, Michael J.,(2009)Female túngara frogs vary in commitment to mate choice, Behavioral Ecology vol. 20 issue 6 2009. p. 1153-1159

Vélez, Manuel J.; Brockmann, H. Jane. (2006), Seasonal variation in selection on male calling song in the field cricket, Gryllus rubens. Animal Behaviour vol. 72 issue 2 August, 2006. p. 439-448