Tag: evolutionary biology

Arrested Development Pays Off for Male Orangutans: Meek Ones Often Get the Girls

By Sarah Zhang | May 17, 2012 12:00 pm

orangutan
A sexually mature male with cheek flanges, throat pouch, and very long fur.

Why would a sexually mature male orangutan want to look too young to father children? Just ask male dung beetles or goby fish. All these species have two types of males: big, aggressive ones that elaborately woo females and smaller sneaker males who, well, sneak behind the backs of the bigger ones. Both can end up successful fathers.

Male orangutans become sexually mature around age 10, but some will stay in arrested development for up to 20 years, even after fathering children of their own. These immature-looking males don’t have the broad cheek flanges, throat pouches, and long orange hair we normally associate with male orangutans. They also don’t produce the long calls that mature-looking males use to attract mates. Even with none of these secondary sex characteristics, male orangutans can get mates and have children. A previous study that tracked an orangutan population in Sumatra for 27 years found that 6 of 11 new babies were fathered by the immature-looking males.

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CATEGORIZED UNDER: Living World

Getting Big Takes Time…Millions and Millions of Generations, Say Biologists

By Veronique Greenwood | January 31, 2012 3:21 pm

elephant
Creatures as large as elephants are unusual; it takes a long time to evolve such size.

How long does it take for a mammal as small as a mouse to evolve into something as large as an elephant? A really, really long time, a recent study has found: about 24 million generations, at minimum.

To get that number, researchers looked at the evolution of body mass over the last 70 million years, after the dinosaurs went extinct and surviving animals expanded into the ecological niches they left behind. That estimate is far longer than earlier estimates, which, extrapolating from bursts of super-fast evolution in mice, range from just 200,000 to 2 million generations. Such speedy evolution, in actuality, is probably not sustainable over the long term—hence the lengthy new estimate.

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CATEGORIZED UNDER: Living World

One Species, Ten Patterns? Why Poison Dart Frogs Dress Differently

By Veronique Greenwood | November 8, 2011 12:22 pm

frogs
Above, the real deal; below, the clay models used to test predators’ reactions to local and foreign frog markings.

Sometimes, you have to make a thousand frogs from modelling clay to make your point.

A single species of poison dart frog sports ten completely different coloration patterns, depending on where they live. Are these color divisions being encouraged by the birds that prey on them?, wondered evolutionary biologist Mathieu Chouteau from the University of Montreal. To find out, he set out 1800 clay frogs, made by himself and his (saintly!) girlfriend, in the Peruvian forest.

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CATEGORIZED UNDER: Living World

Study: Fish Have Been Jumping on Land for 150 Million Years and Hiding it From the Fossil Record

By Douglas Main | October 11, 2011 2:01 pm

Jumping fish!Mosquitofish can leap with “skill and purpose.”

How did animals move from water to land? The answer may have just got a little murkier. A study published this month in the Journal of Experimental Zoology found that two distantly related fish share a similar method for jumping about on land, suggesting that a common ancestor evolved this ability long ago. But unlike amphibious fish such as the mudskipper, which has pectoral fins adapted to “walking” on land, these fish have no specialized equipment for leaping, and would therefore leave no evidence of their talent behind in the fossil record.

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CATEGORIZED UNDER: Environment, Living World

After 13-Year Underground Adolescence, Billions of Cicadas Will Soon Burst Forth

By Veronique Greenwood | May 5, 2011 6:00 pm

cicada

What’s the News: In another glorious reminder of how weird nature really is, it’s time to get ready for the swarm: This May, after spending 13 years underground, huge populations of cicadas will emerge in the southern U.S. to molt, sing their riotous mating tunes, and breed. It’s a brief coda to their long adolescence in burrows 30 cm beneath the soil—by July, they will be dead, and their children will be beginning their years of exile from the surface.

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CATEGORIZED UNDER: Living World
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