Mammals – Page 55

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Can Evolution Repeat Itself?

February 10, 2005

A press release from University of Chicago reported today that “115-million-year-old fossil of a tiny egg-laying mammal thought to be related to the platypus provides compelling evidence of multiple origins of acute hearing in humans and other mammals” (emphasis added in all quotes). The fossil apparently shows inner-ear bones in the monotreme lineage that supposedly […]

Fossils

Bat Theory Strikes Out

January 28, 2005

An international team of biologists set out to write the family history of bats, a story that is “largely unknown,” they admitted in Science.1 They didn’t have much to go on. “The fossil record is impoverished,” their research confirmed, so they tried to piece together a phylogenetic story by combining all that is known about […]

Mammals

Hippo to Whale: Missing Chain

January 26, 2005

Despite claims to the contrary,2 whale and hippo evolution are poorly understood. That’s the gist of a paper in PNAS this week1 that tries to connect the dots between hippopotami (artiodactyls) and whales (cetaceans) and other groups of mammals. There’s lots of missing dots: The origin of late Neogene Hippopotamidae (Artiodactyla) involves one of the […]

Dinosaurs

This Badger Ate Dinosaurs for Breakfast

January 12, 2005

BBC News claims a new fossil discovery published in Nature,1 a large badger-like carnivorous mammal, ate dinosaurs for lunch. But then again, who knows what time of day the Cretaceous restaurants were open? The fossil, another in a series of spectacular finds from the Liaoning Province in China, is creating a sensation, because […]

Darwin and Evolution

Introducing the Stretch & Squish Theory of Evolution

December 14, 2004

How do you squish an arm into a wing, or stretch a fin into a leg? This sounds like the silly putty theory of evolution.

Human Body

Monkeys Have No Ear for Music

December 13, 2004

Consonance and dissonance have no meaning to monkeys, studies have shown. Nature Science Update reported on experiments on cotton-top tamarins showing that, unlike humans, they do not find consonant tones more pleasing than dissonant ones. “If you want to look at the evolution of music it’s important to do these types of studies,” says Laurel […]

Birds

Crows and Apes Related by Convergent Evolution

December 9, 2004

Scientists have noticed that crows have some of the same tool-making skills as apes, and in fact, are even better tool makers. How could such vastly different animals show such similar mental skills? Science1 explains this as another example of convergent evolution: Discussions of the evolution of intelligence have focused on monkeys and apes because […]

Biology

Platypus Has 10 Sex Chromosomes

October 29, 2004

The duck-billed platypus has thrown another curveball at evolutionary theory. Long puzzling to phylogenists for its mosaic of features that make it seem part mammal, bird and reptile, it has now revealed a genome with 10 sex chromosomes – 10 X in the female, and 5 X plus 5 Y in the male. Moreover, the […]

Human Body

Your Brain Hums While Idling

October 11, 2004

Your brain is 100% occupied when watching and concentrating on things, and still processing at 80% in the dark when idle, say researchers at University of Rochester. Opening your eyes only adds 20% more brain activity to the 80% while in neutral. The amount of neural processing going on in idle mode surprised the researchers. […]

Amazing Facts

Your Eyes Have Automatic Light Meters

October 1, 2004

Every pupil knows that pupils constrict in bright light and dilate in dim light, but how? Physiologists had assumed the retina signalled the iris muscles, but now it appears there is an independent mechanism in the iris itself, at least in birds, and probably in mammals, too. A report in EurekAlert summarizes a finding from […]

Amazing Facts

Submarine Engineers Admire Penguins

September 10, 2004

An ocean engineer from MIT, Franz Hover, says “we never miss marveling at them,” speaking of penguins. In the cover story of Science News,1 the submarine designer elaborates: Under the power and guidance of its versatile flippers, a penguin can move through the water faster than 10 miles per hour, turn almost instantaneously, and leap […]

Fossils

Genes Fail to Reveal Evolutionary Pattern in European Mammals

August 27, 2004

One would think an examination of DNA from fossils would track the animal’s geographical distribution as they evolved. However, a study reported in PNAS1 failed to find any correlation in European mammals after the last glaciation. Hofreiter et al. report: Here, we analyze mtDNA sequences from cave bears, brown bears, cave hyenas, and Neandertals in […]

Birds

Humans Lose Some, Win Some in Animal Olympics

August 17, 2004

Imagine humans competing in Olympic events with animals. Astrobiology Magazine predicts we would lose many events, but excel in others: “In most cases of physical competition, the animals beat us at our own games,” says the website’s staff writer, Dr. David Noever. 100 Meter Sprint: Cheetah wins the gold at 3 seconds. Silver goes to […]

Mammals

Hire a Gopher to Rototill Your Land

August 2, 2004

We may holler at them when they dig up our lawns and gardens, but pocket gophers are an important part of the ecosystem, say Jim Reichman and Eric Seabloom in a UC Santa Barbara press release. They change the nutrient availability for plants, among many things: They act like little rototillers, loosening and aerating the […]

Cell Biology

How Cells Build Hard Parts

July 26, 2004

You have rocks in your head, and it’s a good thing, or you would die of starvation and imbalance. Living things have need of inorganic structures for various functions. Can you name the mineral structures in your body? The answer is: bone, dentin, enamel and otoliths. The last three are specific to your head. Dentin […]

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