Before the first birds could take flight, they needed a lift from an unexpected source: colourful feathers. As well as giving birds the most colourful plumage on earth, it seems pigment factories in their feathers primed their feathery dinosaur ancestors for flight by creating feathers of many different shapes. The same pigment factories may also have turbocharged the proto-birds’ metabolism, helping them into the air.
This insight comes from a study of cellular pigment factories called melanosomes from the feathers, hairs and skin of 181 living birds, mammals and reptiles, plus 13 fossils of ancient lizards, turtles, dinosaurs and pterosaurs.
Julia Clarke of the University of Texas at Austin and her colleagues found that melanosomes suddenly became much more diverse in the lineage leading to birds. This happened at the same time that feather-like appendages appeared in maniraptoran dinosaurs, the forerunners of birds. These “pinnate” feathers resembled the familiar branched structure of modern bird feathers, and contained vastly more diverse melanosomes, in terms of their length, width and shape than the samples from ancient lizards and dinosaurs….
But it’s not just about feathers. The melanosome diversity explosion may also have led to higher metabolic rates in the forerunners of birds. Such rapid metabolisms are essential for powered flight.
"Many of the genes involved in the melanin colour system are also involved in other core processes such as food intake, stress responses, reproductive behaviour and more," says Clarke. That means the change in pigment could be linked to larger changes in the animals’ energetics and physiology.
This is corroborated by the modern animals, where melanosome diversity is linked to metabolism. “Only in living warm-blooded terrestrial vertebrates which independently evolved higher metabolic rates did we find the melanosome diversity we also see in feathered dinosaurs,” says Clarke.
(via New Scientist)
Photo: Analysis for the distribution of shapes of melanin-containing organelles (melanosomes) in fossil and living amniotes shows that fuzz-covered dinosaurs like Sinosauropteryx share similarities with living lizards, turtles and crocodilians. In these living taxa color and the shape of the melanosomes are not linked in such a way that color can be reconstructed from melanosome shape alone. Melanosomes in Sinosauropteryx don’t presently tell us if this animal was brown, blackish or grey. However, feathered dinosaurs are similar to birds, and we can estimate their color. Credit: Li et al. (authors).
Journal reference: Nature, DOI: 10.1038/nature12973
If the moon were only 1 pixel on your screen, how big would the rest of the solar system be?
Just click this link, I beg you, and prepare to have your mind blown.
Absolutely amazing. Fantastic work by designer Josh Worth.
For a a different look at the problem of cosmic distance, check out my video “How Big is the Solar System?”:
And for lots more fun ways to look at the scale of the universe maybe watch this one called (naturally) "The Scale of the Universe":
Seersucker on my mind for some reason.
More cloth types used for dress shirts
Have you ever read Trimalchio in West Egg? You may well have without realizing it, since that was an early title for F. Scott Fitzgerald’s The Great Gatsby.
Authors often change the titles of their novels before publication – either as their thoughts develop, or at the request of the publisher. To celebrate World Book Day, we’re going to test your knowledge of working titles. Can you identify which famous books were nearly called something completely different?
I do not understand this “male privilege” bullshit.
What. Fucking. Privileges. Do. Men. Have.???????
Name them. I swear, I challenge you to name these “male privileges” and be able to prove them.
Come on, I…
(Source: , via periodicperspectives)