Tag: evolution

Fossils Reveal Four New Species of Ancient Whales

By Breanna Draxler | February 19, 2013 8:09 am

These are the teeth of an undescribed, new species of toothed baleen whale in the genus Morawanocetus, from Orange County, California. Image courtesy of Meredith Rivin, Dr. John D. Cooper Archaeological and Paleontological Center

Paleontologists in California announced this week that fossils excavated in the early 2000s represent four new species of ancient whales. The toothed baleen whales apparently stuck around longer than scientists once thought, and they may hold clues about how and when whales evolved from toothy giants to the baleen-equipped beasts we see today.

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CATEGORIZED UNDER: Environment, Living World, Top Posts

Blueprints for Mouse Burrows Coded in Their DNA

By Breanna Draxler | January 17, 2013 2:20 pm

Image credit: Vera Domingues/Hopi Hoekstra, Harvard University

A burrow is just a hole in the ground, right? Wrong. Different species of mice have very different burrow designs, and a new study suggests that a mouse’s architectural know-how is written in its DNA: Mice constructed these species-specific burrows even when they had never seen one before.

Researchers examined the burrowing behaviors of two related mouse species. The deer mouse makes a simple burrow, just a short tunnel that leads to a nest. The closely related oldfield mouse puts a little more feng shui in its design, extending the entry tunnel and adding a back door for quick escapes from the nest. To see if the blueprints for these burrow designs were based on instinct, researchers brought the mice into the lab.

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CATEGORIZED UNDER: Living World, Top Posts

Paleontologists Use 3-D Models to Rewrite Evolution

By Breanna Draxler | January 16, 2013 10:56 am

Illustrated version of an Ichthyostega tetrapod, zooming in on the correct orientation of two vetrebrae reconstructed in the study. Credit: Julia Molnar.

When the earliest animals hauled themselves out of the ocean and evolved legs, they began flopping and eventually walking down the evolutionary path toward terrestrial life as we know it. The fossil remains of these first four-legged creatures, called tetrapods, have played a crucial role in understanding this sea-to-land transition. The spine is of particular interest, but it turns out that paleontologists had it backward.

Tetrapod fossils have long proven difficult to study since the bones often can’t be separated from the petrified material that surrounds them. Using a new modeling method, researchers bombarded these 360-million-year-old fossils with high-energy X-rays in order to make 3-D models of the ancient remains. The new method, reported in Nature this week, allowed researchers to isolate the otherwise-hidden bones and see them in their original orientation.

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CATEGORIZED UNDER: Human Origins, Living World, Top Posts

Capturing the Courtship Rituals of Bizarre Birds-of-Paradise

By Breanna Draxler | December 12, 2012 10:10 am

Birds-of-paradise are living, breathing, dancing, singing examples of evolutionary extremes. Isolated in the rainforests of New Guinea, these species evolved in the absence of predators. As such, their designs have been driven by sexual selection—female preference, rather than physical necessity, per se—and the results are over the top.

Cornell University ornithologist Ed Scholes and National Geographic photojournalist Tim Laman have combed the rainforests of New Guinea and Australia for the past eight years in search of every one of the birds-of-paradise’s 39 species. The research duo has amassed some 40,000 images of these ornate birds performing their elaborate courtship rituals. The project’s official website is set to launch sometime in January, but they have released a trailer to tide viewers over until then. The only thing more astounding than the images of these avian anomalies is the evolutionary history that created them.

 

CATEGORIZED UNDER: Environment, Living World, Top Posts

The Evolutionary Game That Led One Species of Cuckoo to Wear Two Disguises

By Sophie Bushwick | August 6, 2012 2:30 pm

cuckoo
An adult reed warbler feeds a common cuckoo chick,
not recognizing the baby bird as a parasite

In the world of birds, cuckoos are pretty unpopular. Maybe it’s something about how they lay their eggs in others’ nests so that their chicks will steal food and attention from the natural-born chicks. This can kick off an evolutionary arms race that researchers are already familiar with: the cuckoo eggs evolve to look more and more like the host eggs, and the hosts evolve to get better and better at recognizing the foreign eggs.

Now researchers have discovered another cuckoo-versus-host evolutionary race running in parallel—and it has led to the evolution of two different forms of the same species of female cuckoo.

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CATEGORIZED UNDER: Living World

Louisiana Set to Use Public Funds to Teach Creationism & Climate Denialism

By Sophie Bushwick | June 27, 2012 9:00 am

Louisiana’s new voucher program will kick in during the upcoming school year, giving students in failing public schools the funds to attend certain highly rated public schools and private institutions. Some of these private schools will be spreading ignorance to their students by using curriculum that openly clashes with modern science.

One textbook used by many private schools makes the creationist claim that no transitional fossils showing evolutionary changes have ever been found, which is simply not true. “This gradual change from fish to reptiles has no scientific basis,” the book reads. “For the change, to have taken place many transitional forms would have been developed. However, no transitional fossils have been or will ever be discovered because God created each type of fish, amphibian, and reptile as separate, unique animals. Any similarities that exist among them are due to the fact that one Master Craftsman fashioned them all” [poor reasoning and use of commas theirs; emphasis ours].

This excerpt comes from a high-school science book used in the Accelerated Christian Education (ACE) curriculum, an educational tool in many Louisiana schools, like the Eternity Christian Academy in Calcasieu Parish, which is offering spots for 135 voucher students. British musician Jonny Scaramanga, who attended an ACE school while growing up as a Christian fundamentalist, has published this and other alarming textbook passages on his blog, Leaving Fundamentalism, including the creationist claim that the second law of thermodynamics disproves evolution.

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CATEGORIZED UNDER: Human Origins, Top Posts

Mosquitoes' Clever Little Trick to Survive Collisions With Raindrops: Being Little

By Sophie Bushwick | June 6, 2012 11:23 am

What’s the News:

For a mosquito, venturing out during a heavy rainstorm means risking collisions with droplets 50 times its weight—but this doesn’t deter it from living in humid, rainy climes. In fact, researchers have discovered that the mosquito’s low mass, along with a sturdy exoskeleton, helps it weather (so to speak) the impacts of raindrops without much trouble.

How the Heck:

  • The researchers confined three-millimeter-long Anopheles mosquitoes in a “drop impact chamber,” an acrylic cage five centimeters wide and twenty centimeters tall. To keep the mosquitoes confined and airborne, a mesh top blocked the insects’ exit while still admitting water droplets, and the cage vibrated once every few seconds to prevent the bugs from landing on the walls.
  • A high-speed camera filmed the collisions as the researchers either pumped jets of water into the chamber with the speed of a falling raindrop, or released slower droplets to let the camera get a better view. Although a direct body hit could drag the bug down in a five- to twenty-body-length fall before the mosquito escaped the water, droplets tended to hit the mosquitoes’ long wings and legs instead, rolling off their water-repellant bodies and only slightly skewing their flights.

 

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CATEGORIZED UNDER: Environment, Top Posts

Rest Easy, Men: Shrinkage (of the Y Chromosome) Has Apparently Stopped

By Veronique Greenwood | February 24, 2012 9:33 am

Y chromosome
The Y chromosome, at the bottom right of this set of human
chromosomes, is dwarfed by the X.

Over the last few decades, scientists and journalists have speculated that the end of man—men, that is—was nigh. The biological reason for this possibility is the ever-shrinking Y chromosome: 300-200 million years ago, the Y, like females’ X chromosome, had hundreds of genes, but it now contains less than 80, 19 of which code for specifically male traits such as sperm production. This remarkable contraction set people’s imaginations spinning, especially after an opinion piece said in Nature 10 years ago that the Y chromosome might disappear, as it already has in voles, in 10 million years.

A Nature paper published this week, however, may indicate that the Y is sticking around. Biologists at the Whitehead Institute have compared the Y chromosome of rhesus monkeys with the human Y chromosome, and they’ve found that the two have the same number but one of key male-specific genes. This implies that the human Y chromosome’s shrinkage, at least when it comes to key genes, stopped at least around 25 million years ago, when the common ancestor of humans and rhesus monkeys was alive. The team says that this 25 million years of stasis indicates that the Y’s days of sloughing genes are over, that the genes it carries now are the essential ones and cannot be removed without seriously impacting reproductive function, while the genes lost in the past were expendable.

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CATEGORIZED UNDER: Health & Medicine, Living World

Study: Prions Can Be Helpful Engine of Evolution, Rather than Cause of Disease

By Sarah Zhang | February 17, 2012 1:18 pm

spacing is important
Yeast under a microscope.

What’s the News: Prions get a bad name—the very word is a portmanteau of “protein” and “infection,” which suggests that they’re up to no good. And there’s obviously some truth to this: Prions are a type of protein that have alternative folded forms, and if they aggregate into insoluble clumps, they can cause problems like mad cow disease. But prions might also be a key part of evolution. A new survey published in Nature found prions in 1/3 of yeast strains, and 40% of the traits they conferred were beneficial.

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CATEGORIZED UNDER: Living World, Top Posts

Why We Can't Just Get Rid of the Genes That Let Us Get Infected

By Veronique Greenwood | February 13, 2012 12:35 pm

cold
Takin’ one for the team.

What’s the News: Clearly, as anyone suffering through a cold right now can tell you, our immune systems aren’t all they could be when it comes to keeping us disease-free. And what’s worse, the same viruses that have some people hawking up phlegm for weeks can give their roommates or spouses no more than a brief sniffle, hammering home the fact that the immune system wealth isn’t distributed evenly. Why hasn’t evolution dealt with this problem already and given us all impenetrable defenses?

As it turns out, it’s not just that evolution takes its own sweet time. It’s also that a species benefits from having individuals be immune to some things and vulnerable to others, a new study shows.

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CATEGORIZED UNDER: Health & Medicine, Top Posts
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