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Sixth Mass Extinction Event Occurring

written by: Sean Fears•edited by: Niki Fears•updated: 11/13/2009

From time to time, mass extinctions have dramatically altered the landscape, seascape, and bioscape of planet Earth. Indications are that a mass extinction event is occurring again, with half of the Earth's species at risk UC-Santa Barbara researchers are using science to decide what must be saved.

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    The evidence is going from persuasive to overwhelming that we are currently in the midst of a mass extinction event. Scientists at UC Santa Barbara have been studying flowering plants across the globe and have come to the conclusion that about 50 percent of the world’s flora are at risk of extinction. In this research, genetic diversity is being used as a deciding factor in which species are the most critical. Grasslands such as prairies are remarkably diverse in terms of plant life, as well as important bases for their relative ecosystems.

    According to the research, genetic diversity and ecosystem criticality go hand in hand; this is understandable, since genes are an indicator of function, and those functions uniquely represented only by certain key species are the ones that would be the most in danger of disappearing due to extinction. Indeed, specialized niches would provide less of an opportunity (or incentive) for change, which would in turn tend to insure that key species did not diversify.

    Researchers cited the buttercup as such a species, since there are few relatives to take its place or perform its function. If that biomass represented by the buttercup should disappear, other species in the grasslands cannot take easy advantage of that empty niche, significantly affecting the total amount of biomass in the ecosystem in question. Such a change is critical for our own purposes, since a major function of grasslands is carbon sequestration, a function removed in many parts of the world as grasslands were replaced with agricultural fields. In addition, species that rely on unique plants are less likely to be able to adapt to changes that adversely impact the plants that they rely on for shelter or food, potentially exacerbating already stressful conditions and negatively influencing far-reaching parts of the ecosystem.

    Forty different studies and 177 species formed the basis for this research; by looking back at evolutionary patterns through the changes of yesterday, these scientists will hopefully gain insight into the changes we can expect to occur as the species composition of extant ecosystems changes in the present and future. Such research highlights the extent to which genetic research and mathematical analysis tools are allowing us to peer back into the past through genes as well as fossils.