Introduction
The desert tortoise is a relic symbol of the arid environment (Morafka & Berry 2002). But despite the robust array of evidence suggesting phylogeny, certain populations of the desert tortoise remain elusive (Berry et al. 2002). Genetic evaluation has resolved some phylogeny issues by establishing a new species within the clade (Murphy et al. 2011).
Traits and behaviors also play a role in the evolutionary history of the desert tortoise. Many traits and behaviors exhibited by the desert tortoise may be symplesiomorphies or exaptations rather than desert adaptations (Morafka & Berry 2002). Other characteristics of the desert tortoise include behavioral modification to drought and variation between sexes in space use (Duda et al. 1999; Harless et al. 2009).
Upper respiratory tract disease is also characteristic of the desert tortoise. Varying levels of Mycoplasma agassizii may cause clinical symptoms of the disease. An enzyme-linked immunosorbent assay (ELISA) was used to detect M. agassizii antibodies in tortoise blood. Two factors were concluded to affect the mortality and morbidity rate of URTD—climate and M. agassizii antibodies within tortoise blood (Sandmeier et al. 2009; Sandmeier et al. 2013).
Finally, conservation efforts such as translocation of desert tortoises into wild populations were assessed. Gene flow and genetic variability were described among different populations of desert tortoise (Murphy et al. 2007; Edwards et al. 2004; Edwards & Berry 2013).
The ‘Species’ Problem
Species are the fundamental unit of evolution and measurement for biodiversity conservation. Speciation occurs by the splitting of a subpopulation from its main population, resulting in phenotypic and genotypic change, both of which ...
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... these populations include the need for the placement of culverts and corridors (Edwards et al. 2004).
Conclusion
Due somewhat to the paucity of research, the desert tortoise remains an enigmatic species (Berry et al. 2002). This fact is troubling particularly because the species habitats have become so fragmented and encroached upon. Management strategies to conserve the desert tortoise require a multifaceted approach of genetic, behavioral and habitat assessment (Edwards et al. 2004). Further possible effects of climate change on the desert tortoise have not been assessed although it has been noted that changes in El Nino patterns may disrupt foraging plant material for juvenile desert tortoises (McCoy 2011). The patterns of ecological decline for the desert tortoise may react synergistically in unknown ways making extinction a very viable threat to these species.
Isle Royal is located fifty-six miles north of Michigan’s Keweenaw Peninsula. It is the largest wilderness area in Michigan (USNPS, 2014). The island is surrounded by Lake Superior, which creates a cooler temperature. This results in arctic plant species growth on the island. There are only eighteen mammal species present on the island because most mammals cannot make the trip across the frozen great lake (USNPS, 2014). The need for an ice bridge is not the only environmental factor that is stopping the migration of animals; there is also the severe cold, and also wind and fog (Vucetich, 2012). Some species such as caribou and coyote have found the island to be too intense and have gone extinct (Vucetich, 2012). Due to the harsh weather and isolation of the island, humans have never regularly lived on the island (Vucetich, 2012). Some of species that are present such as the red squirrel are becoming their own subspecies due to its separation from the mainland (USNPS, 2014). The isolation of Isle Royal is what makes it a great place to conduct research, it has very low human interaction and the species that are on the island will have been and continue to be isolated from the mainland.
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...e ability to climb and jump are two other traits that help this mammal survive. Its claws are hard and curved which permits it to scale the tall forest trees; its hindfoot 180 degrees so it can push off and jump incredible distances (Fischer).
Biodiversity is influenced by landscape fragmentation at various scales of space and time. The extinction of ecosystem types and component species may cause an increased patchiness of the landscape, resulting in lower population sizes and decreased connectivity. As a result, inhabitants may experience decreased dispersal abilities and lowered gene flows between populations.
Biodiversity is the variation and amount of species across the globe, or within in a specific geographical habitat. There are three different areas of study within biodiversity; ecological diversity, species diversity and, genetic diversity. Science Book Species diversity is the variety of different organisms and relationships within a specific species, this essay will discuss the declining of species diversity among sea turtles and the implications it has on the worldwide seas. I have chosen to research about the topic because, sea turtles are believed to have been alive during the Jurassic period. However, now all seven sea turtle species are critically endangered or vulnerable, due to human activities such as; commercial fishing, bycatch and, climate change. (WWF, OCEANA, ACTIONBIOSCI)
The Galapagos Islands, located about 600 miles west of continental Ecuador, contain a rich history of settlement and exploration and represent a living example of evolution that is still relevant today. For centuries, this chain of volcanic islands has been used uniquely by various cultures based off distinct needs. What has remained the same however is the fact that island isolation has forced many animal and plant species to adapt differently from one another based off their island’s environmental conditions, creating a living model of microevolution over time. Today, these models tend to be the primary resources used by biology professors when teaching their students evolutionary topics.
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A Tortoise is a Land dwelling reptile from the Chelonian family that has a large round shell, short feet, and sturdy legs. To keep a perfect temperature, tortoises perform something called estivation or a state of underground dormancy, primarily during summer. Tortoises are some of the longest living animal in the world, living on average over one-hundred and fifty years
Both the snow leopard and the green turtle are classified as endangered under the IUCN red list with decreasing population trends. Both live in very different habita...
According to Darwin and his theory on evolution, organisms are presented with nature’s challenge of environmental change. Those that possess the characteristics of adapting to such challenges are successful in leaving their genes behind and ensuring that their lineage will continue. It is natural selection, where nature can perform tiny to mass sporadic experiments on its organisms, and the results can be interesting from extinction to significant changes within a species.
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In Wilcove’s article, it is examined within the 50 states the four types of animals being discussed such as mammals, birds, reptiles, and amphibians with the possibility of becoming extinct or critically imperiled determined by The Nature Conservancy (TNC). David Wilcove states that, “A total of 2,490 imperiled species, subspecies, and populations fit these criteria” (Wilcove, Rothstein, Dubow, Phillips, & Losos, 1998, p. 607). In response, within these 2,490 animals at risk the science of these problems is that their home is destroyed, and when introduced to a new environment they cannot adapt to the normal life in the same manner. Native animals cannot compete with the new species discovered and...