Diversity And Diversity

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Biodiversity is the variation among living organisms in different ecosystems, and is the result of 3.5 million years of evolution. Evolutionary diversification, offset by extinction events, is responsible for the continuous increase in biodiversity over the course of Earth 's history, from unicellular organisms to the creation of millions of multicellular organisms. Evolutionary diversification leads to the process of speciation, creating large variation between species in terms of evolutionary age, and over geographical space and time (Santamaria & Mendez., 2012). In the past, there was vast biological diversity, but with the human population on Earth increasing, species are disappearing at a rate 100 - 10,000 times higher than previously…show more content…
Patterns of biodiversity are often a result of environmental parameters influencing the selection of traits suitable to a particular habitat. An observable pattern of biodiversity is found across different latitudes of the globe, where there is a clear distinction between the density of species in low latitudes near the equator, and higher latitude temperate areas. The latitudinal biodiversity gradient describes this pattern, observing that species density is much higher in the tropics than in temperate areas (Dowle et al., 2013). Many hypothesize that in the past, differential rates of extinction or speciation created these gradients of biodiversity across geographic areas. High extinction rates have previously come from unusual temperature extremes, for example in the Pleistocene extinction, where it is hypothesized that higher latitudes felt these climate changes more severely, and therefore resulted in higher rates of extinction (Dowle et al., 2013). While disturbances and extinction events such as this destroy many species, they also create variant niches that allow…show more content…
Rapid evolutionary changes arise from selection caused by human actions, rather than natural selection, and affect the dynamics of populations, communities, and ecosystems (Santamaria & Mendez, 2012). Anthropogenic disturbances such as harvest, and habitat loss and fragmentation create evolutionary consequences that are difficult to reverse. The harvesting of fish, for example, selects for large, adult members of the population, causing changes in the fish population to favour earlier reproduction, and as a result affects nutrient cycling in their aquatic environment and food web interactions (Santamaria & Mendez, 2012). This anthropogenic selection decreases the adaptive potential of the population or species by reducing the gene pool and genetic variation. Habitat loss and fragmentation is also a major driver of biodiversity loss by decreasing population size and isolating populations. Genetic exchange between groups of individuals requires that their breeding ranges overlap. Human alterations to the physical landscape changes species ' distributions and can therefore affect gene flow by reducing the degree of contact between groups and creating reproductive barriers that decrease both fitness and genetic integrity of populations and species (Crispo et al., 2011). Small, isolated populations

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