Tag Archives: fossil record

The Winners of Mass Extinction: With Predators Gone, Prey Thrives

*Extinction of fishes 360 million years ago created natural ecology experiment*

In present-day ecology, the removal or addition of a predator in an ecosystem can produce dramatic changes in the population of prey species. For the first time, scientists have observed the same dynamics in the fossil record, thanks to a mass extinction that decimated ocean life 360 million years ago.

What was bad for fish was good for the fish’s food, according to a paper published online in Proceedings of the National Academy of Sciences. Researchers from the University of Chicago, West Virginia University and The Ohio State University found that the mass extinction known as the Hangenberg event produced a “natural experiment” in the fossil record, with results that mirror modern observations about predator-prey relationships. (more…)

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Uncertain Future for Joshua Trees Projected with Climate Change

FLAGSTAFF, Ariz. — Temperature increases resulting from climate change in the Southwest will likely eliminate Joshua trees from 90 percent of their current range in 60 to 90 years, according to a new study led by U.S. Geological Survey ecologist Ken Cole.

The research team used models of future climate, an analysis of the climatic tolerances of the species in its current range, and the fossil record to project the future distribution of Joshua trees. The study concludes that the species could be restricted to the northernmost portion of its current range as early as the end of this century. Additionally, the ability of Joshua trees to migrate via seed dispersal to more suitable climates may be severely limited. (more…)

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Fossil Bird Study Describes Ripple Effect of Extinction in Animal Kingdom

GAINESVILLE, Fla. — A University of Florida study demonstrates extinction’s ripple effect through the animal kingdom, including how the demise of large mammals 20,000 years ago led to the disappearance of one species of cowbird.

The study shows the trickle-down effect the loss of large mammals has on other species, and researchers say it is a lesson from the past that should be remembered when making conservation, game and land-use decisions today. (more…)

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Earth’s Sixth Mass Extinction: Is It Almost Here?

*Steep decline of many animal species warns that Earth is on the brink*

With the steep decline in populations of many animal species, scientists have warned that Earth is on the brink of a mass extinction like those that have occurred just five times during the past 540 million years.

Each of these “Big Five” saw three-quarters or more of all animal species go extinct.

In results of a study published in this week’s issue of journal Nature, researchers report on an assessment of where mammals and other species stand today in terms of possible extinction compared with the past 540 million years.

They find cause for hope–and alarm. (more…)

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