Tag Archives: elephant

How Evolution Shapes the Geometries of Life

COLLEGE PARK, Md. – Why does a mouse’s heart beat about the same number of times in its lifetime as an elephant’s, although the mouse lives about a year, while an elephant sees 70 winters come and go? Why do small plants and animals mature faster than large ones? Why has nature chosen such radically different forms as the loose-limbed beauty of a flowering tree and the fearful symmetry of a tiger?

These questions have puzzled life scientists since ancient times. Now an interdisciplinary team of researchers from the University of Maryland and the University of Padua in Italy propose a thought-provoking answer based on a famous mathematical formula that has been accepted as true for generations, but never fully understood. In a paper published the week of Feb. 17, 2014 in the Proceedings of the National Academy of Sciences, the team offers a re-thinking of the formula known as Kleiber’s Law. Seeing this formula as a mathematical expression of an evolutionary fact, the team suggests that plants’ and animals’ widely different forms evolved in parallel, as ideal ways to solve the problem of how to use energy efficiently. (more…)

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Importance of Gene-Gene Interactions Shown in Study

Gaining more insight into predicting how genes affect physical or behavioral traits by charting the genotype-phenotype map holds promise to speed discoveries in personalized medicine. But figuring out exactly how genes interact has left parts of the map invisible.

In a paper published in Proceedings of the National Academy of Sciences, North Carolina State University genetics researchers reveal some of the hidden portions of the map, showing that complicated networks of gene-gene interactions in fruit flies greatly influence the variance in quantitative traits, or characteristics that are influenced by multiple genes – like sensitivity to alcohol or aggression. (more…)

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Airborne Technology Helps Manage Elephants

Washington, D.C. – For years, scientists have debated how big a role elephants play in toppling trees in South African savannas. Tree loss is a natural process, but it is increasing in some regions, with cascading effects on the habitat for many other species. Using high resolution 3-D mapping, Carnegie scientists have for the first time quantitatively determined tree losses across savannas of Kruger National Park. They found that elephants are the primary agents—their browsing habits knock trees over at a rate averaging 6 times higher than in areas inaccessible to them. The research also found that elephants prefer toppling trees in the 16-to-30 foot (5-8 m) range, with annual losses of up to 20% in these height classes. The findings, published in Ecology Letters, bolster our understanding of elephant conservation needs and their impacts, and the results could help to improve savanna management practices.

“Previous field studies gave us important clues that elephants are a key driver of tree losses, but our airborne 3-D mapping approach was the only way to fully understand the impacts of elephants across a wide range of environmental conditions found in savannas,” commented lead author Greg Asner of Carnegie’s Department of Global Ecology. “Our maps show that elephants clearly toppled medium-sized trees, creating an “elephant trap” for the vegetation. These elephant-driven tree losses have a ripple effect across the ecosystem, including how much carbon is sequestered from the atmosphere.” (more…)

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People Aren’t Born Afraid of Spiders and Snakes: Fear Is Quickly Learned During Infancy

There’s a reason why Hollywood makes movies like Arachnophobia and Snakes on a Plane: Most people are afraid of spiders and snakes. A new paper published in Current Directions in Psychological Science, a journal of the Association for Psychological Science, reviews research with infants and toddlers and finds that we aren’t born afraid of spiders and snakes, but we can learn these fears very quickly. 

One theory about why we fear spiders and snakes is because so many are poisonous; natural selection may have favored people who stayed away from these dangerous critters. Indeed, several studies have found that it’s easier for both humans and monkeys to learn to fear evolutionarily threatening things than non-threatening things. (more…)

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