The Importance Of Climate Change

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Since Earth came into existence, it has been transforming geographically, climatically, and biologically. In the past, these changes have been caused by completely natural occurrences such as volcanic eruptions, and cyclical as well as random astronomical events (Seidl, 2011). Based on the fossil record, species have been able to persist through past climatic changes; however, this record also indicates, through a number of extinctions, that the ability to adapt is much more restricted during rapid climate change (Davis & Shaw, 2001). Presently, the Earth is in a warming period that is primarily anthropogenic. Since the mid-twentieth century, industrialization has increase carbon dioxide levels, and in turn, temperatures are rising at a rate greater than any other time during the last 60 million years (Kraatz & Barnosky, 2007). The rapid change in climate that we are currently facing is multifaceted and could mean a change in other climatic factors such as precipitation, drought, growing season and day length as ranges shift (Jump, Peñuelas, & Hurtt, 2005). A large change in these factors could threaten population dynamics, species diversity, and agricultural productivity (Anderson, Panetta, & Mitchell-Olds, 2012). In addition to climate change, extant natural populations face other anthropogenic threats ‘paleocommunities’ did not face, such as habitat fragmentation and degradation, pollution, invasive species, and overhunting (Anderson et al., 2012). Among these threats, habitat loss is the most crucial: Habitat fragmentation decreases effective population sizes and increases geographic isolation, often eroding genetic variation. Isolation can limit species’ abilities to track climate via migration and disrupt gene flow among ... ... middle of paper ... ...ed their production of ATP, making them genetically preeminent at dispersal (Parmesan, 2006). Dispersal capacity has also been demonstrated to be a limiting factor for ancient species survival. Hadly and colleagues (2004) studied two small mammal species, and found that, although they had similar ecological response, their genetic response to climate change differed. These opposite genetic responses can be attributed to their dispersal ability and therefore the amount of gene flow that occurred through migration. The fossil record indicated that Thomomys talpoides and Microtus montanus were reduced in population size as a result of climate change during the late Holocene. T. talpoides decreased in genetic variation as the population size diminished while M. montanus increased in genetic variation because it was able to migrate longer distances (Hadly et al., 2004).
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