User:Lauterbach.7/sandbox

Topic
How have the various subspecies of the species Giraffa camelopardalis (Giraffe) evolve due to their environment?

Annotated Bibliography
1)Brown, D. M., Brenneman, R. A., Koepfli, K. P., Pollinger, J. P., Milá, B., Georgiadis, N. J., ... & Wayne, R. K. (2007). Extensive population genetic structure in the giraffe. BMC biology, 5(1), 57.

Through the use of mitochondrial DNA sampling, it was concluded that seven separate clades of giraffe do have differing genetic structure. However, neighboring giraffe clades were found to have similar genetic structure, allowing the seven clades to be split into two larger clades, northern and southern. The results of the mitochondrial DNA sampling shows that there was at one time a sharp geographic separation between groups, with factors of climate, arid and dry periods in question, causing diversification of the species and their evolved pelage. This article shows a great, in-depth look into the question at hand. The researchers take it a step further by diving into the genetic DNA of the animals, rather than just looking at the outside. The work seems well thought through and highly reliable. This paper fits in well with the question of how the giraffe subspecies evolved based upon their environments. It helps prove that the giraffe evolved into its subspecies due to geographical differences.

2)Hassanin, A., Ropiquet, A., Gourmand, A. L., Chardonnet, B., & Rigoulet, J. (2007). Mitochondrial DNA variability in Giraffa camelopardalis: consequences for taxonomy, phylogeography and conservation of giraffes in West and central Africa. Comptes rendus biologies, 330(3), 265-274.

After extensive research of mitochondrial DNA of various giraffe, it was determined that three distinct lineages of giraffe exist, the northern giraffe, the Angolan giraffe, and the southeastern giraffe. Within these groups exist subspecies that were determined to have significant nucleotide dievergence within their DNA. The nucleotide divergence suggests the diversification of the subspecies took place during Late Pleistocene where geographic barriers may have existed, stopping gene flow and allowing for evolution. Arid and glacial periods mixed with warmer climates may have been reason enough for this diversification, along with savannah rages mixed with tropical dense forests, and ultimately leading to the different subspecies. This source gives a second look into the mitochondrial DNA aspect of the giraffe subspecies. It backs up the first source and proves itself as well as the first source to be highly reliable. This source can also be implemented into the answer of how giraffe subspecies evolved, and how geography can cause such a result.

3)Jeugd, H. P., & Prins, H. H. (2000). Movements and group structure of giraffe (Giraffa camelopardalis) in Lake Manyara National Park, Tanzania. Journal of Zoology, 251(1), 15-21.

This article gives a deep look into the social behaviors and movements of giraffe. The different social patterns of males and females are reviewed and it explains the herding system that giraffe tend to follow. With different habitats in which giraffe live, density, range-size, and mobility of the giraffe vary within the habitats. Group stability ranges from group to group and ranges from loose herds to stable groups. The article is very well written covering multiple areas of giraffe social behavior. This source can further the research by comparing not only the difference in coloration of giraffe, but also the social behavior of the different subspecies based on the environments in which the range.

4)Lydekker, R. (1904, June). On the Subspecies of Giraffa camelopardalis. In Proceedings of the Zoological Society of London (Vol. 74, No. 1, pp. 202-229). Blackwell Publishing Ltd.

An extensive look at the subspecies of the Giraffa Camelopardalis, this article goes deep into an explanation of the markings, coloration, and aspects of the each subspecies. Each subspecies has distinctive patterns and characteristics, such as horn and body shape characteristics. This paper gives an in-depth look at the different subspecies and how they are classified. The research seems well thought and planned out, with a lot of thorough information on the subspecies. It could potentially help answer the question of how the giraffe subspecies evolved by allowing for a great introduction on how the subspecies actually differ from one another.

5)Pellew, R. A. (1984). The feeding ecology of a selective browser, the giraffe (Giraffa camelopardalis tippelskirchi). Journal of Zoology, 202(1), 57-81.

This research looks into the browsing habits of the giraffe. Giraffe are highly selective when it comes to their browsing in order to get the proper nutrition. Seasonal changes such as the dry season and the wet season cause changes to the Acacia and other browse growth in certain areas, leading to changes in habitat in which the giraffe prefer to feed. Differences in male and female browsing also appear during the separate seasons. Based on the sex of the giraffe, there are nutritional requirements that their selective feeding must meet, causing different choices in habitats in which to browse. The article is very reliable as it used many references. Thorough research on different food sources in certain sections of habitats was done in order to determine the selectivity of the giraffe feeding. This information could be used to further research on giraffe subspecies evolution by showing how different habitats with different food sources could have caused migration of certain groups leading to the evolution of the several subspecies.

Wikipedia Article that Treats Topic
https://en.wikipedia.org/wiki/Genetic_isolate

Three Talk Suggestions
Extensive, specific biological examples of each type of genetic isolation/speciation would allow for a greater understanding of their definitions, and how genetic isolation can lead to this type of evolution.

An explanation of how evolution through genetic isolation can be highly influenced and driven by differences in a population's environment. Yes, an extrinsic barrier can cause genetic isolation and speciation, but how do these barriers cause this speciation and evolution?

The subspeciation of the giraffe, Giraffa camelopardalis, could be added as a great biological example of allopatric speciation, as climatic and geographical separations within the species have lead to changes in their phylogenetics and evolutionary characteristics, shown through an analysis of their mitochondrial DNA. Lauterbach.7 (talk) 21:45, 1 October 2014 (UTC)

Addition and Citation
The giraffe, Giraffa camelopardalis, can be seen as a representation of the allopatric speciation that occurs due to genetic isolation of a population. Several clades of giraffe show differentiation within their mitochondrial DNA, varying between regions throughout Africa. These differences date back to the middle of the Pleistocene epoch, and coincide with genetic isolation due to climatic and geographical separations within the population, allowing for the evolution and subspeciation of the separate subspecies of giraffe and differences in their pelage.

Final Paper
Title:Is genetic isolation to blame for the subspeciation of Giraffa camelopardalis? It is widely accepted by the Association of Zoos and Aquariums and the Giraffe Conservation Foundation that there exists nine subspecies of giraffe, Giraffa camelopardalis. With some subspecies more recognizable than others, and some higher in numbers, few people know that the nine subspecies exist, ranging in color, habitat, and geographical location. All across the countries of Africa, giraffe roam the wild and browse the lands for food, shelter, and mates. It is a wonder how such a magnificent animal, so tall, majestic, and uniquely patterned has come to evolve in itself, with its tall neck, but the question of how nine different subspecies have evolved proves to be an even greater challenge to answer. This proves to be a great question for evolutionary biology, as it can help introduce and explain many ideas of how evolution occurs, its definitions and its mechanisms. It takes a major topic of evolutionary biology, the diversification of species, and illustrates it through a modern day example. The G. Camelopardalis is a living example of the process of speciation. Extensive research on the social structure, movement, and migration patterns of giraffe herds, lends a bit of evidence toward how the species may have diverged into its nine subspecies. A great deal of research has also been conducted with the subspecies’ mitochondrial DNA and its loci substitutions, giving insight to the time of subspeciation through the molecular clock and what could have caused these genetic differences during certain time periods. Together, the migratory patterns and DNA research of the giraffe provides insight into how the species has diverged.

A look at the differences between the nine subspecies can put the inquiry of the mechanism of subspecies into perspective. The most commonly known subspecies of giraffe, G. c. reticulate, has a brown-orange, highly geometric pattern which is universally recognized. G. c. reticulate populates southern Somali, Ethiopia, and northern Kenya. The other eight subspecies, however, are not so familiar. The G. c. angolensis, found to live in Namibia, Zambia, and Botswana has a relatively light, smoky appearance. The G. c. antiquorum, residing in Chad, the Central African Republic, Cameroon and the Congo, shows pale, irregular markings that also cover their inner legs. The G. c. Camelopardalis, one of the least populous subspecies of giraffe, is found mainly in western Ethiopia and has four-sided, chestnut brown spots that do not make their way to the legs. The G. c. giraffe, inhabiting much of South Africa, exhibits a star shaped pattern that extends all the way down the legs. The G. c. peralta, found only in Niger and the rarest of all subspecies, has tan spots on a creamy background. The G. c. rothschildi, ranging in Uganda and Kenya, dawns rectangular dark spots with seemingly no markings on the legs. The G. c. thornicrofti, restricted to eastern Zambia’s South Luangwa Valley, sports large, dark, leaf-shaped spots that find their way down the length of the legs. Last but not least, the G. c. tippelskirchi, lives in Kenya and into southern Tanzania and has dark, vine-leaf shaped, jagged spots on creamy brown lines. With different ranges and highly varying patterns, could genetic isolation play a role in this subspeciation? An extensive look into the social behavior and movements of giraffe herds and their mitochondrial DNA could suggest that geographic separation between populations has resulted in these very different nine subspecies.

Giraffe, though a herd animal, have been studied to travel in very loose herds. As ruminants and eating a diet of about 75 pounds of food per day, giraffe spend most of their day browsing for food. Though their diet varies between grass, bark, and leaves, giraffe are most often found browsing for leaves, most frequently from the Acacia tree. A study done by Pellew (1984) looked at the feeding ecology of giraffe and showed that the loose-herd social structure of the giraffe species allows individuals to be highly selective when browsing, freely changing the area in which they browse, the time at which they browse and the food they choose. The ecology of the giraffe can be variable depending upon the nutritional requirements needed for reproductive success and the changing forages based upon the season. There can be a high effect of the wet and dry seasons of the African climate on the browsing of giraffe (Pellew 1984). As different food sources flourish differently in varying areas during the changing seasons, this gives the giraffe population an incentive to migrate to areas of higher food value as a way to make sure they achieve their nutritional requirements. Though large-scale population migrations have not been observed in more current giraffe populations, small-scale movements following the growth of Acacia and other food sources have been observed within populations of giraffe (Pellew 1984). Research by Fennessy (2009) indicated that due to the different seasons, giraffe range location can change from the desert range to the mountain range, in order to follow the Acacia growth patterns. These small-scale migrations following food sources and changes in range geography could be evidence to suggest earlier, larger migratory movements of these loose-herd animals and the possibility for greater genetic isolation, leading to their subspeciation. Another study by Jeugd and Prins (2009) demonstrated that giraffe show a difference in movement varying between the sexes. Females tend to show a more stable residence while male giraffe show variation within their ranges and migratory routes. Males may show a greater interest in migration, not based upon food source, but based upon female choice. The males may migrate to different herds looking for a better opportunity with females, a chance for greater reproductive success and increasing their fitness, the success of passing on their genes (Jeugd & Prins 2009). The greater male migrations that are seen in giraffe populations today could be reminiscent of more massive migratory patterns of the male giraffe and could have been cause for sexual selection in different ranges throughout the giraffe populated area, causing the spread of different genes between separate herds and populations. Though this sexual selection could cause gene flow between herds, these group and individual small-scale migratory patterns could have led to some sort of genetic isolation, whether it be geographical or natural selection based upon environment, keeping the genes within the same populations and leading to subspeciation. Not only do giraffe provide reason for geographical separation and isolation, but their loose-herd social structure is highly controlled by kinship, the sharing of similar genes between individuals. Though it has long been believed that giraffe form loose-social bonds with random individuals, research shows that these associations are nonrandom and are formed between familiar individuals and offspring-parent relationships. Though females prefer to socialize with females, there is extreme attraction between recognizable individuals (Bercovitch & Berry 212). There is a great deal of reason behind socializing with kin and familiar individuals, as altruism, the protection of relatives by putting oneself at risk, and the coefficient of relatedness justify such actions. Giraffe will associate with these familiar individuals for protection of themselves and their families. These loose-herd associations can help the passing on of fit genes and can aide in reproductive success. This strong desire to stay within a familiar group, and to base social structure off of kinship and relatedness could provide reason for genetic isolation, only reproducing with those familiar individuals, passing on genes that will stay within the population, and could have caused the differences in patterns and colorings within each subspecies. This kinship based social system is also affected by a fission-fusion system, where herd size and composition changes through time as individuals move as a steady parental group stays. This fission-fusion system, however, allows for a great deal of long-distance communication and short-distance reunion, keeping herd individuals in check and part of the group (Bercovitch & Berry 2013). Therefore, though herd composition is ever changing, related individuals are staying in touch with one another and presumably keeping the gene pool within their herd, allowing for proliferation of different types of phenotypic variation among separate populations. Furthermore, a great deal of research has focused on the mitochondrial DNA of the different subspecies of giraffe in order to take a look at their molecular clock. This is a way to determine when the subspeciation may have begun and what events during those time periods could have led to such subspeciation. As explained earlier, giraffe currently exhibit differences in patterns and colorations in abrupt range locations with no physical or geographic separation. Research by Brown et al. (2007) looked into the DNA and genetic structure of these different populations provided some insight into when and how this diversification occurred. An extensive study on the subspecies G. c. thronicrofti showed variation from other subspecies and suggested genetic isolation between the separate subspecies (Fennessey et al. 2013). Even though there exists variation between the mtDNA and subspecies of giraffe, some similarities exist between neighboring range subspecies. G. c. thronicrofti and G. c. tippelskirchi showed a shared haplotype within their mtDNA which suggests that genetic isolation through the founder effect or genetic drift within a population has caused the subspeciation of the giraffe (Fennessey et al. 2013). Continual research with the mtDNA of the giraffe species as a whole, and the subsets, takes a look into the molecular clock and provides suggestions of the time periods for diversification. MtDNA substitutions suggest that the giraffe diversified around the time of the Late Pleistocene, also in accordance with the fossil record. This suggests a great deal of previous geographical separation between populations, preventing gene flow and allowing for the subspeciation through allopatric events (Hassanin et al. 2007). Another study of the subspecies G. c. angolensis shows a great lack of genetic diversity within the population itself, suggesting an event of migration around geographical barriers and causing a lack of gene flow within the population (Brenneman et al. 2009). This is all evidence toward an early geographical separation between extant populations of giraffe, causing lack of gene flow, founder effects, and genetic drift within these separated populations, and allowing for a great deal of diversification This evidence suggests the mechanism of evolution of the nine subspecies that are recognized today. A great area of research focuses on migratory movements and mtDNA as a way to determine how the existing nine subspecies have evolved. Extant giraffe populations show minor migratory movements throughout changing seasons in order to follow the growth patterns of the Acacia tree and other food sources, providing evidence for larger migratory movements in the past, possibly around geographical barriers. Research taking a look at the mtDNA of individuals from several of the nine subspecies and the differences between loci both within the same subspecies and between different subspecies has been able to provide some more concrete evidence of how exactly genetic isolation has played a role in the diversification of the giraffe species. The mtDNA gives a perspective from the molecular clock point of view, allowing for the ability to place the evolution of the separate subspecies at a certain time in history.

The giraffe species is highly diversified, with nine subspecies recognized, and thoughts of naming separate species in the works. It is a wonder how the nine subspecies could have evolved to show their different appearances and colorations at the macro level while they are not currently separated by any geographical or physical barrier. Great amounts of research have been done on the giraffe, in many different areas, ranging from their height and their blood pressure, to their cow-calf relationships. With a look at migratory patterns and being able to put a time stamp on when diversification occurred, geographic separation can be provided as reasonable cause for genetic isolation and the ultimate evolution of the nine subspecies.

Works Cited

1.Bercovitch, F. B., & Berry, P. S. (2013). Herd composition, kinship and fission–fusion social dynamics among wild giraffe. African Journal of Ecology, 51(2), 206-216.

2.Brenneman, R. A., Louis Jr, E. E., & Fennessy, J. (2009). Genetic structure of two populations of the Namibian giraffe, Giraffa camelopardalis angolensis.African Journal of Ecology, 47(4), 720-728.

3.Brown, D. M., Brenneman, R. A., Koepfli, K. P., Pollinger, J. P., Milá, B., Georgiadis, N. J., ... & Wayne, R. K. (2007). Extensive population genetic structure in the giraffe. BMC biology, 5(1), 57.

4.Fennessy, J. (2009). Home range and seasonal movements of Giraffa camelopardalis angolensis       in the northern Namib Desert. African Journal of Ecology, 47(3), 318-327.

5.Fennessy, J., Bock, F., Tutchings, A., Brenneman, R., & Janke, A. (2013). Mitochondrial DNA analyses show that Zambia's South Luangwa Valley giraffe (Giraffa camelopardalis thornicrofti) are genetically isolated. African Journal of Ecology, 51(4), 635-640.

6.“Giraffe Subspecies.” The Giraffe Conservation Foundation. n.p., 2014. Web. 23 Oct 2014. 

7.Hassanin, A., Ropiquet, A., Gourmand, A. L., Chardonnet, B., & Rigoulet, J. (2007). Mitochondrial DNA variability in Giraffa camelopardalis: consequences for taxonomy, phylogeography and conservation of giraffes in West and central Africa. Comptes rendus biologies, 330(3), 265-274.

8.Jeugd, H. P., & Prins, H. H. (2000). Movements and group structure of giraffe (Giraffa camelopardalis) in Lake Manyara National Park, Tanzania. Journal of Zoology, 251(1), 15-21.

9.Pellew, R. A. (1984). The feeding ecology of a selective browser, the giraffe (Giraffa camelopardalis tippelskirchi). Journal of Zoology, 202(1), 57-81.

Minimum 300 Word Addition to Genetic Isolate
https://en.wikipedia.org/wiki/Genetic_isolate

== Genetic Isolation and the Giraffa camelopardalis == Genetic isolation can happen in a variety of different ways. There are many ongoing, current research projects evaluating how various species have diverged through the process of genetic isolation, the giraffe, Giraffa camelopardalis, being one example. Giraffe are recognized to have nine separate subspecies, each varying in their coloration and patterns. After much research, it is accepted that genetic isolation is at fault for allowing the G. camelopardalis species to diverge. There are various ideas behind how genetic isolation has occurred within the giraffe species. Extant giraffe populations have been studied to make small-scale migratory movements based upon wet and dry seasons within the African climate. The feeding ecology of giraffe is highly researched and it has shown that giraffe will follow the growth patterns of the Acacia tree based upon seasonal change, changing giraffe locations from mountain ranges to desert range. Though this is not evidence for current day genetic isolation, it suggests evidence for past large-scale migrations that may have caused separation within the species, caused genetic isolation, and led to the beginnings of the subspeciation of the giraffe population. Giraffe also tend to travel in loose social herds. However, these loose social herds have been researched to be based upon a non-random system. This non-random system follows a trend of kinship, or the sharing of similar genes between individuals. These loose-social herds that keep kin and familiar individuals within the same group, with only small movements of individuals from the herd, only for them to return to the same group. This is evidence for genetic isolation by interaction only between familiar individuals. This is cause for interbreeding and the accumulation of certain alleles, alleles that could potentially code for pelage color and pattern, within a population, causing differences between populations and ultimately the subspeciation of the giraffe species. Geographic separation has also been studied to play a role in the genetic isolation of the giraffe. The mitochondrial DNA of giraffe has been studied for mutations and loci substitutions between subspecies and suggests diversification around the Late Pleistocene, where geographic isolation was likely. The giraffe is a great example of how genetic isolation can happen in a number of ways and can lead to the diversification of a species.