The Dirt: This Week in Nature

First Evidence That Increased Carbon Dioxide in Oceans Harms Fish.

The Australian Research Council’s Centre of Excellence for Coral Reef Studies has announced that it conducted research on the increased levels of CO2 in ocean water and its effect on fish. The results indicate that increased CO2 levels disrupt the neurochemistry of fish brains, which causes significant interference with their behavior and sensory abilities. Specifically, fish show impaired ability to hear and are less able to evade predators when CO2 levels are elevated. Worse, the scientists think that the interference in systemic and physically affects the entire fish brain.

Read more at Physorg.com.

Miniature Frog Sets Vertebrate Record.

Hidden in the New Guinea forests is a frog so small that it appears more like an insect than a vertebrate. The new species, Paedophryne amanuensis, is approximately a quarter of an inch long. It eats, not surprisingly, very small insects. The frogs hide in moist leaf litter on the forest floor. It is not yet known which predators feed on the tiny frogs, but it is suspected that they are prey for scorpions.

Read more at bbc.

Dinosaur Runway – Fancy Headwear and Mutual Sexual Selection.

An article in Scientific American discusses the possible links between head crests and mutual sexual selection in dinosaurs and pterosaurs. The size and variety of the crests seem to indicate that they were sported by both males and females, and part of their purpose may have been to select the most fit individuals for mating. The authors further suggest the possibility that the evolution of feathers displaced the role of crests as a vehicle for mutual sexual selection. Modern birds, of course, rely upon their excellent color perception to assess potential mates based upon their colorful plumage. Dinosaurs, which also are believed to have had excellent color vision, may have evolved feathers for that same reason.

Read more at Scientific American.

Evolutionary Lost and Found.

For 165 years, slides and fossils collected by paleontologists, including Charles Darwin himself, had been languishing in a wooden cabinet in the British Geographical Survey Headquarters in Britain. Now, a serendipitous re-discovery of the cache is proving to be an exciting surprise for scientists. One scientist said that the first slide he looked at was from Darwin’s famous expedition to the Galapagos Islands aboard the Beagle and signed by Darwin himself. The entire collection has been photographed and is now online.

Read more at RedOrbit.

Heart Throbs Direct Boa’s Main Squeeze.

When a boa constrictor has an animal in its grasp it needs a foolproof way to know when it’s dead. Scientists have now discovered that boas feel the heartbeat of their prey and squeeze until it fades away. Even when experimenters used a fake beating heart in dead prey, the snakes continued to squeeze well past what is normal. Moreover, the skill appears to be innate. It may seem to be ‘overkill’ to have developed this system for mammals, for which a crushing squeeze quickly leads to death. However, the experimenters surmise that because reptiles, which also serve as boa dinner, have such slow heartbeats and can withstand considerable crushing, there was an evolutionary advantage for boas in measuring the heartbeat of all prey.

Read more at Live Science.

Birds Take Advantage of Higher Wind Speeds.

Airliners are not alone in wanting to optimize fuel efficiency. It appears that the wandering albatross, as well as other birds, are taking full advantage of the increase in wind speeds in the Southern Ocean. Because climate change seems to increase wind speeds over oceans, birds are getting to their foraging and nesting destination faster than usual. That means more successful breeding and healthier animals. Scientists warn, however, that this may be a short term advantage because much higher winds in the wrong direction may one day become a distinct disadvantage for the birds.

Read more at Audubon Magazine.

Living With Moose and Wolves.

For the 54th consecutive winter, a team of specialists moves into Isle Royale, a frozen island wilderness surrounded by Lake Superior. As they do every year, the team documents the relationship between moose and the wolves that prey on them. In this New York Times article, the author describes the exceptionally harsh winter conditions that face the inhabitants of the island. Temperatures can get so low that trees can split open in the night. A chart showing the changing interconnection between moose and wolf populations is an interesting example of natural balance.

A Warm Welcome to Microcebus gerpi.

A new species of lemur has been identified in Madagascar. Microcebus gerpi is about the size of a hamster and lives in the rainforests of eastern Madagascar. It has been apparently hiding in plain sight among other lemur species. Unfortunately, the lowland regions that compromise this lemur’s natural environment are not protected and the threat of human incursion will put pressure on the lemur’s survival.

Read more at Discovery.

How Long Does It Take For Single Cell Organisms to Become Multicellular?

The surprising answer seems to be: not long at all. In an experiment carried out by scientists at the University of Minnesota, single cell yeast were grown under conditions that favored those yeast cells that fell to the bottom of the flask. In just a few weeks, more and more yeast cells were ending up at the bottom on the flask, indicating that they were adapting to the experiment. When the surviving yeast cells were examined under a microscope it was discovered that the yeast had transformed itself from single cell organisms to multi-cell organism that grew together in a snowflake like form. One scientist, Richard Lensky of Michigan State University, commented on the results: “It shows that a major transition in evolution — going from unicellular to multicellular life forms — might not be as hard to achieve as most biologists have long thought.”

Read more at New York Times.

Bower Bird Courtship Ritual Relies On Illusion.

Australian male bower birds construct elaborate bowers from twigs, bones and rocks. Because the bower is constructed in a tunnel-like manner and it and the male are inspected by interested females from one end of the tunnel, optical illusion plays an important role. If done properly, the male bower’s legerdemain will make him appear larger and more virile than he might otherwise be. In addition, the more interesting the illusion, the more time the female will spend observing it, which in turn increases the chances of mating. Not surprisingly, it was determined that males which produced the best illusions more often than not got the girl.

Read more at Live Science.