User:Gruhl.1/sandbox

This is for Evolution EEOB 3310.

Topic
How has wing-assisted incline running (WAIR) and the evolution of the forelimb/wing function contributed to avian flight?

Source Descriptions
This paper experimentally examines locomotor mechanics involved in WAIR. This looks at the difference in wing motion between WAIR and normal flight. It looks at the difference between forelimb and hindlimb function in locomotion and argues this may have been a factor in the evolution of flight. This also provides details in which this would not be a factor in evolutionary determining avian flight.

This paper summarizes WAIR and experimentally tests the locomotor response of different hatchlings. This paper goes on to say how WAIR may be the unexplained answer to the evolution of flight, because of the similarities of the wings of feathered theropods dinosaurs. It has experimental evidence for incline running performance of the chukar partridge, and discusses the similarities within extant birds of the forelimbs of small winged “proto-birds”

This paper examines the transition from ground to aerial locomotion. WAIR may be an evolutionary intermediate for avian flight. It describes the forelimbs necessity for avian flight that other proponent hypotheses fail to mention. WAIR behavior may show an intermediate type of wing or wing behavior.

This paper describes how WAIR and controlled flapping descent (CFD) are intermediate adaptive stages between ground and air locomotion. It experimentally tests muscles in pigeons for certain characteristics related to WAIR and CFD. The paper believes that WAIR is an extant model for the transition from ground and air locomotion because of the muscle characteristics upon examination.

This paper summarizes how WAIR may be an intermediate step between ground and air locomotion for a predator-prey reasoning. In this paper, it experimentally tests between wing adaptation and neurological control of the wings in which is responsible for locomotion.

Suggestions Posted on Talk Page of Wing Assisted Incline Running
These suggestions are also posted in the talk page:

Adding a section for which specific species or other types of birds engage in WAIR other than Galliforms and Australian Brushturkeys.

Add to the “Response” section, to add additional hypotheses/data why WAIR might not be a step in the evolution of avian flight.

Add a section specifically to the chukar partridge, as there is a lot of information and specific studies that could be added in terms of the development, mechanics and aerodynamics of WAIR in this species of bird. Gruhl.1 (talk) 17:11, 30 September 2014 (UTC)

As of October 14, 2014, there have been no comments on my suggestions for the talk page. Gruhl.1 (talk) 15:21, 14 October 2014 (UTC)

https://en.wikipedia.org/wiki/Talk:Wing-assisted_incline_running is the website for the talk page.

Added sentence(s) to main page of Wing Assisted Incline Running
When baby chukars hatch, they have not yet developed their flight feathers. As the babies develop, it takes approximately one week for feathers to appear, and about three weeks for the ability to fly. As the the baby chukars grow and before flying for the first time, they utilize WAIR as a transition to adult flight.

https://en.wikipedia.org/wiki/Wing-assisted_incline_running is the main website page of my added sentence(s).

I could not just add one sentence without it being a very long run-on sentence, so I broke it up into three short sentences.

There is a citation to the reference included at the end of the sentence(s) on the main page of the article. It is also reference number 5 at the bottom of this sandbox page.

Additions to Wing-Assisted Incline Running
I created the section named Explanation of using WAIR over normal flight

Here is the added text: There is a plausible explanation backed by research as to why these galliformes utilize WAIR instead of normal flight to locate themselves into a tree. WAIR uses less energy than normal flight. Fewer muscles are used in the process of WAIR than normal flight, specifically pectoral and shoulder muscles which contribute to wing flapping. This provides an additional explanation as to why birds continue to utilize WAIR: it is faster than normal flight take-off, and running requires less energy than does flying. Therefore; the hindlimbs, in conjunction with the wings, may produce quick bouts of energy which may allow the bird to catch prey. This strategy also allows energy to be stored for use in a fight-or-flight situation such as to escape becoming eaten or caught. . WAIR imposes less aerodynamic and physical forces than normal avian flight on the bird, an advantageous trait which may increase fitness. WAIR could have been used for balance purposes. Many theories propose that the manifestation of WAIR in birds is for predatory escape purposes, in that they are able to run up extremely steep and past vertical slopes (such as the trunk of a tree) to escape from a ground-dwelling predator. Another reason for the manifestation of WAIR may be for dispersal or to find food or resources, but this idea is mostly proposed as a survival strategy. Whether it is to evade predation, catch prey, enhance reproductive success, or simply a variation imposed for dispersal, flight among avian creatures has evolved to be a highly successful trait.

I also added the second part of the section named response. Here is my addition to that section:

Evidence has been proposed against the WAIR hypothesis, stating that it is too simplistic and does not take additional information into effect. There have been additional mechanisms suggested, such as climbing claws, that would have provided an advantage for the birds, but are absent in fossil records or extant birds. Other arguments against WAIR include a lack of fossil evidence and no additional intermediate or transition stages available for study which would provide supplementary evidence for WAIR.

The total word count is 331 words, which does not include citations or footnotes. Here is the URL to the website: https://en.wikipedia.org/wiki/Wing-assisted_incline_running Gruhl.1 (talk) 06:41, 17 November 2014 (UTC)

FINAL DRAFT STARTS HERE
Wing-Assisted Incline Running

The origin of avian flight has been long debated. Birds and other organisms capable of flight have evolved certain adaptations and traits for evolutionary success in response to environmental pressures. Adaptation for flight is both a process and a result of natural selection; the mechanism that drives evolutionary change. Whether it is to evade predation, catch prey, enhance reproductive success, or simply a variation imposed for dispersal, flight among avian creatures has evolved to be a highly successful trait. There are many hypotheses that attempt to explain the evolution of flight. The Arboreal model and the Cursorial model are two major hypotheses that attempt to reveal the origin of flight among birds and other extant species capable of flight. This continues to be an active area of research among evolutionary biologists. Wing-assisted incline running (WAIR) is a particular version of the Cursorial model that attempts to explain the evolution of avian flight.

The Cursorial model is commonly referred to as the ground-up or running model, whereas the Arboreal model is referred to as the tree-down or gliding model, where organisms “fall” off of elevated structures and glide to the ground (Dial et al. 2006). The Cursorial model established the idea that an adaptation occurred in the extremities of organisms such as bipedal dinosaurs. It says that their fingers, arms or legs evolved to have wing-like structures first aiding the creatures in running, then transitioning to jumping and then ultimately leading to flight (Ostrom 1974). WAIR is a version of this Cursorial model hypothesis.

The mechanistic concept of WAIR is that birds use the improved foot traction provided by the downward force from their flapping wings, and this improved grip on the surface allows them to scale inclines greater than normally achievable (Bundle and Dial 2003). This allows birds to navigate the wild by running up inclines sometimes even greater than 90 degrees (vertical) while employing WAIR (Dial 2003). The central idea behind WAIR is that when a bird flaps its wings, it is using aerodynamic forces to assist in movement by enhancing the ability of its hindlimbs to move forward towards its destination, coming from an increase in grip (Tobalske and Dial 2007). This suggests that birds evolved the ability of flight, seen today, through running up inclines and flapping their wings (Dial 2003). The term evolved indicates a change in the DNA of birds over generations. To introduce a new allele into the population requires mutation, a random change in an organism’s genotype, which sometimes affects its phenotype, or the physical expression of the trait. Usually rare and deleterious, this mutation, or series of mutations introduced an advantageous allele into the population for flight characteristics. The mutation(s) may have produced better wing development, or another trait in birds which led to enhanced aerodynamics and flight capability. Once in the population, the trait may go through different transitional stages where natural selection selects for only those with a fitness advantage, or those capable of flight. Research shows that WAIR may be the transitional stage between running and flight (Bundle and Dial 2003; Tobalske and Dial 2007).

Conducted research found that a few species participate in WAIR. The chukar partridge, Alectoris chukar, is the most commonly studied species of bird exhibiting WAIR (Tobalske and Dial 2007). It is believed that birds evolved from feathered dinosaurs, namely Archaeopteryx (Ostrom 1974). In this transition from dinosaur to bird, additional species of birds also utilized wing-flapping and running to scale steep slopes, including the Australian brush turkey (Dial and Jackson 2010). The order of galliforms birds, which includes the chukar partridge, have typically been the species used in research (Dial et al. 2006; Dial 2003). Research suggests chukar partridges and these other birds use the transitional WAIR model for flight.

How these different species of studied birds achieve the locomotive strategy rests upon the aerodynamics of their body. The wings, feathers and limbs all play a role in the propulsion of the bird. The mechanics of WAIR may help to explain its evolutionary adaptation for the origin of avian flight. The aerodynamic forces that the bird produces when it flaps its wings are used for multiple functions. Using their wings for propulsion creates a stronger normal force away from the surface, thus increasing their traction by increasing the frictional coefficient, thus allowing them to “stick” to the surface better, counteracting the gravitational force, and allowing them to run up very steep slopes (Bundle and Dial 2003).

There are many situations in which this technique of locomotion may be advantageous for the bird. Many theories propose that the manifestation of WAIR in birds is for predatory escape purposes, in that they are able to run up extremely steep and past vertical slopes (such as the trunk of a tree) to escape from a ground-dwelling predator (Bundle and Dial 2003; Jackson et al. 2011). Another reason for the manifestation of WAIR may be for dispersal or to find food or resources, but this idea is mostly proposed as a survival strategy (Dial et al. 2006).

There are other reasons explained by the mechanisms of WAIR as to why this model of the evolution of flight may be selectively advantageous for birds. Birds’ appendages can be broken down into hindlimbs (legs) and forelimbs (wings). The major mechanism of WAIR is an aerodynamic force created by the wings when the bird is flapping that causes a downward force onto the surface, effectively increasing its traction by increasing its grip (Dial 2003; Bundle and Dial 2003). Another important factor is the center of mass, which is lowered toward the surface, and increases the affinity for the surface of the slope, allowing the bird to traverse locations inaccessible by normal running (Bundle and Dial 2003).

Today, chukar pigeons are fully capable of flight. There is a plausible explanation backed by research as to why these galliforms utilize WAIR instead of normal flight to locate themselves into a tree. WAIR uses less energy than normal flight (Jackson et al. 2011). Fewer muscles are used in the process of WAIR than normal flight, specifically pectoral and shoulder muscles which contribute to wing flapping (Jackson et al. 2011). This provides an additional explanation as to why birds continue to utilize WAIR: it is quicker than normal flight take-off, and running requires less energy than does flying. Therefore; the hindlimbs, in conjunction with the wings, may produce quick bouts of energy which may allow the bird to catch prey (Dial et al. 2006). This strategy also allows energy to be stored for use in a fight-or-flight situation such as to escape becoming eaten or caught (Dial and Jackson 2010; Jackson et al. 2011). WAIR imposes less aerodynamic and physical forces than normal avian flight on the bird, an advantageous trait which may increase fitness (Dial and Jackson 2010).

Specific case studies have shown WAIR in extant birds such as the chukar partridge, which has undergone extensive investigation in search for observable WAIR locomotion (Dudley and Yanoviak 2011). When baby chukars hatch, they have not yet developed their flight feathers. As the babies develop, it takes approximately one week for feathers to appear, and about three weeks to develop the ability to fly. As the baby chukars grow and before flying for the first time, they utilize WAIR as a transition to adult flight (Tobalske and Dial 2007). In a famous experiment conducted by Kenneth Dial, he shows WAIR in extant chukar partridges. The study included three groups of five chukar partridges. The first group was the control group with no plucked feathers, the second group had their feathers trimmed down 50% and the third group’s feathers were completely plucked. Dial conducted tests to investigate how the differences in the wings affected the birds’ ability for WAIR. The study found that the maximum slope attainable decreased as the amount of available feathers decreased. Dial also altered the surface of the slope in which the birds were running from coarse, to medium coarseness, to smooth and again found a reduction in the ability to use WAIR. In another study giving the bird the option of flight or WAIR, the chukar partridges continued to use WAIR as a way for mobility, even though they were capable of normal flight (Dial 2003; Dial et al. 2006). Structural differences were compared between WAIR and normal flight including wing dynamics. Using high-speed cameras, it was found that during WAIR the wings employed different angles and forces than normal flight (Bundle and Dial 2003). These studies support the hypothesis that WAIR may be a model for the origin of flight, where it is a transition stage from no flight to normal avian flight.

All birds share the same common ancestor, Archaeopteryx, which was part dinosaur and part bird. Looking at the adaptation of wings and the evolution of aerodynamic flight mechanics, WAIR may provide a transitional link between running and flying (Dial 2003). For adaptation in a population to occur, it must confer a fitness advantage, leading to increased reproductive success. Fitness is dictated by an organism’s environment, and this running tactic has been thought to be advantageous for escape purposes, representing a fitness advantage suggesting a shift to flight using WAIR as a transition strategy. The origin of avian flight has many different hypotheses and ideas, and “WAIR provides a model identifying incremental adaptive plateaus by which the evolution of flight may have occurred… and how transitional stages of proto-wings may have been adaptive, particularly to small bipedal cursors” (Bundle and Dial 2003). This is an active area of research in the field of evolutionary biology, and there are many ways in which research can examine WAIR as a transitional model for the evolution of flight. One of those ways is through looking into the anatomy and physiology of the birds themselves. By comparing features such as wing length, shape and size in fossils and extant birds, data can be compiled showing how birds with intermediate features could have used WAIR in their transition to normal flight (Tobalske and Dial 2007). A theory also states that because the transition must take place over plateaus or by steps in morphological and structural features, the transitional steps each must have had a fitness advantage, in this case, it may be explained by wing structures and how WAIR is used by birds with different wing anatomy (Dial et al 2006). Literature on the evolutionary hypothesis of WAIR has indicated that the origin of flight continues to be a work in progress. However, wing-assisted incline running may provide insight into the transition between bipedal foot traffic and normal flight (Dial et al 2006; Jackson et al. 2011). It has been said that evolution is a tinkerer, not an engineer, and the process is slow and takes many years to develop new traits persistent in a population.

Research is ongoing in the field of evolutionary biology for the origin of avian flight. This ancestral behavior may also have been exhibited in a landing form as well, in wing-assisted descent, similar to the Arboreal model of top-down flight. According to research, this may have been used as a survival strategy for young falling out of elevated nests or also for escape, and this concept continues to be researched. (Dudley and Yanoviak 2011). Strategies for the selective advantage of birds using WAIR is also a part of ongoing investigation. WAIR could have been used for balance purposes, and physical adaptations in birds may need to be addressed further in terms of the anatomical and skeletal movement of the body (Bundle and Dial 2003). Using wing anatomy and body movement to explore additional ideas, research is also examining the neuromuscular control of avian extremities and how this could lead to adaptations and morphological traits that give the bird certain selective advantages in the pursuit of flight (Tobalske and Dial 2007).

Evidence has been proposed against the WAIR hypothesis, stating that it is too simplistic and does not take additional information into effect. There have been additional mechanisms suggested, such as climbing claws, that would have provided an advantage for the birds, but are absent in fossil records or extant birds (Nudds and Dyke 2009). Other arguments against WAIR include a lack of fossil evidence and no additional intermediate or transition stages available for study which would provide supplementary evidence for WAIR (Bundle and Dial 2003; Dial et al. 2006).

Wing-assisted incline running (WAIR) is a proposed hypothesis for the origin and evolution of avian flight. Through empirical evidence of morphological and adaptive characteristics in extant species of birds such as the chukar partridge, research has proposed that WAIR is a ground-up mechanism for the transition from running to flight in birds. Upon examining the anatomical characteristics in the hindlimbs and forelimbs (wings) of birds, how they use locomotion to their advantage, and how aerodynamic forces interact to assist the bird in movement, ideas about how birds made the transition from ground to air continues to be an active area of research in the field of evolutionary biology.

References

Bundle, M.W., and Dial, K.P. 2003. Mechanics of wing-assisted incline running (WAIR). The Journal of Experimental Biology 206:4553-4564.

Dial, K. P. 2003. Wing-Assisted Incline Running and the Evolution of Flight. Science 299:402-404.

Dial, K.P., and Jackson, B.E., 2010. When hatchlings outperform adults: locomotor development in Australian brush turkeys (Alectura lathami, Galliforms). Proceedings of the Royal Society Biological Sciences 278:1610-1616.

Dial, K. P., Randall, R. J., and Dial, T. R. 2006. What Use Is Half a Wing in the Ecology and Evolution of Birds?. Bioscience 56:437-445.

Dudley, R., and Yanoviak, S.P., 2011. Animal aloft: the origins of aerial behavior and flight. Integrative and Comparative Biology 51:926-936.

Jackson, B. E., Tobalske, B. W., and Dial, K. P. 2011. The broad range of contractile behavior of the avian pectoralis: functional and evolutionary implications. The Journal of Experimental Biology 214:2354-2361.

Nudds, R.L. and Dyke, G.J. 2009. Forelimb posture in dinosaurs and the evolution of the avian flapping flight- stroke. Evolution 63:994-1002.

Ostrom, J.H. 1974. Archaeopteryx and the origin of flight. The Quarterly Review of Biology 49:27-47.

Tobalske, B.W., and Dial, K.P. 2007. Aerodynamics of wing-assisted incline running birds. The Journal of Experimental Biology 210:1742-1751.

Gruhl.1 (talk) 22:50, 16 November 2014 (UTC)