The Evolution of the Giraffe Neck
Throughout time, one theory has remained constant in terms of why giraffes developed longer necks. The idea, which was presented by Charles Darwin states quite simply that giraffes selected for longer necks in order to reach the food that was higher off the ground during the dry season. No one has ever challenged that idea until 1996. Initially, Gould argued that "the story-the giraffe evolved its long neck in competition to reach scare foliage-is supported by no evidence" (18). That's when two scientists, Robert Simmons and Lou Scheepers made the claim that necks evolved for a very different reason: sexual selection. Within this paper, information will be presented that argues both for and against the theories made by Darwin and Simmons and Scheepers.
Giraffes are placed in the family, Giraffidae, separate from other animals such as the camel, deer, and cow. Typically, giraffes are about 19 feet tall and can weigh as much as 4000 pounds. The evolution of modern giraffes began about 1 million years ago from a similar species known as Giraffa jumae. Those species were known for their massive skeletons and antler-like structures, not found on giraffes of today (Simmons 772). Today, there are nine widely excepted subspecies of the giraffes which are differentiated by the spots on the trunks and their geographic region.
In the article, "Winning By a Neck: Sexual Selection in the Evolution of Giraffes," Simmons and Scheepers state their purpose as to evaluate the theory proposed by Darwin as well as present their own. The theory by Darwin known as the Interspecific Feeding Competition has many assumptions that must hold up for it to be true. One assumption is that tall trees must ...
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... This is shown through the way that the animals feed and the disproportionate increase in neck length compared to other components within the giraffe. The evidence presented in this case offers much more support for the idea that sexual selection is responsible. However, much more investigation must take place in order for the theory to be considered acceptable.
Bibliography:
Works Cited
Brownlee, A. Evolution of the Giraffe. Nature. Vol. 200:1963.
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Gould, Stephen J. The Tallest Tale. Natural History. May 1996.
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Kodrick-Brown, A., and J. H. Brown. Truth in Advertising: The
Kinds of Traits Favored by Sexual Selection. The American
Naturalist. Vol. 124:1984. Pp. 309-323.
Simmons, Robert E. Winning By a Neck: Sexual Selection in the
Evolution of Giraffe. The American Naturalist. Vol.
148:1996. Pp. 771-786.
Dr. Goodall is a well-known British primatologist who has discovered a substantial amount about primates in her many years of research. She has written numerous books, including one that we will be going into depth about called, “Through a Window.” Her book contains personal experiences, research findings, and even pictures to help the readers visualize her scientific breaking moments from her thirty years with the chimpanzees of Gombe. She states that there is are minor differences, and several similarities between humans and the chimpanzees. We will discuss these differences and similarities through their social behavior, intellectual ability, and emotions. To conclude, examine Goodall’s research to adopt what her findings can tell us about our early ancestors, and whether or not her study coincided to the steps of scientific methodology.
: Primates didn’t just appear among Earth, but they evolved. The coevolution has to do with flowers and fruits. Fruits were evolving to get tastier for primates to eat and as primates ate them they spread them around as well. As they ate these new evolved fruits and flowers this invited changes onto their bodies as
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In relation to the findings, two specific species of primates have been found to have coexisted separately in particular locations explored in Kenya. The way they are separated from each other specifically notes how these groups of primates were able to protect themselves from cross breeding with each other. The first specie, Praeanthropus dimorphicus, is notably a predator which could be assumed to have fed on animals surrounding the area. Based on the fossils found on top of the fossils of this specie, these primates could be assumed to have fed on wildebeests ...
Did you know thousands of years ago giraffes did not only live in Africa, but they also lived in North America? We do not see these species in North America anymore because they all died because of their inability to adapt. Giraffes adapted into their environment because the food they were eating was on taller trees and after a while, only the selection with longer necks were left. The giraffes we see today, have longer necks because they are the ones that survived by adapting. As all other animals, giraffes are living things because they get energy, move and grow, reproduce, protect themselves, and adapt to their environment.
The results of this experiment are that when comparing the average mandible length between carnivores and herbivores, the herbivores had the longer mandible length on average. Furthermore, when comparing the average eye length between herbivores and carnivores, the carnivores had larger eyes on average. In Figures 1 and 2 the x-axis represent the two groups of animals being tested and the y-axis represent the average diameter of the length. Figure 1 represents the average mandible length between the two groups of animals. On the same note, the average length of the herbivores mandible length was .806 mm and the average length of the carnivores was .635 mm. Moreover, figure 2 denotes the average eye length between the herbivores and carnivores. Figure 2 displays the average eye length of herbivores which is 0.1579 and the average eye length of the carnivores which is 0.1758. The results of this experiment were that when comparing mandible length between herbivores and carnivores there was a significant
Teeth shape and size- The giraffes teeth are relatively big but also blunt so that they are able to crush there food (leaves and twigs) with a lot of strength until it is able to swallow, the bluntness is also used to help grip the leaves from the tree so that it is easier to pull the leaves and twigs off the tree.
The most prominent difference between Homo erectus and previous species of hominids is the increase in cranial capacity (Washburn, McCown 1972). Over the course of Homo erectus' existence, the cranial capacity increased fr...
1. A giraffe’s habitat consists mainly of savanna and dry open woodland. They prefer to live in warm areas with tall grass to run wild and move freely. They are considered herbivores so they eat leaves off of trees, twigs, shrubs, and mimosa(Australian tree with flowers). A majority of giraffe’s easily adapt to environments that meet their needs. These animals don’t necessarily have predators because of their size. It’s very rare that a large lion pack takes one down. Studies show that they don’t have any animals as their prey.
Amongst social mammals, spotted hyaenas (crocuta crocuta) display a number of unusual traits, including high maternal investment, strong sibling rivalry that may lead to siblicide, female dominance, and masculinization of female genitalia. (1) This paper will concentrate on the masculinization of female genitalia but will also touch on the other traits listed.
First of all, in The Giraffe, people want to harm the tall animal because it creates an uncomfortable atmosphere, which can be seen through the reactions of many characters. As a result, everyone, except the boys, misunderstands the habits of the giraffe, and wants to kill it at the end. One clear example of a negative reaction to the presence of the giraffe can be shown through the police officer’s reaction to the presence of the giraffe: “[…] the policeman who came and said, ‘if you don’t take it away, I’ll kill it with my revolver’ (Senesi 3).” The officer of the law looks upon the giraffe from Africa as if it is a criminal. Since the ...
All the Animals are bewildered as they try to figure out what caused this. Finally the giraffes step forward admit to their part in the dilemma and take they blame. The animals are furious, but being sensible put aside their anger and decide to deal with the situation on hand. All the ...
Exactly when you thought we had enough with Cow, Platypus and Goat Evolution, comes the spin-off that takes the Evolution arrangement to fantastic new statures. Giraffe Evolution!
This paper is all about how giraffes can do amazing things. Such as what they eat and why people hunt them. This paper is also about their characteristics. To find out more about giraffes keep reading this amazing paper. I
Bergman, Jerry. "CRSQ Abstracts, 2014, Volume 50, Number 3 (Winter)." Why Mammal Body Hair Is an Evolutionary Enigma. March 1, 2004. Accessed November 30, 2015.