In On the Origin of Species, Charles Darwin posited that animal lineages with more species should also have more sub-species, or "varieties" in Darwin's terminology. Now, nearly 140 years after Darwin's death, Laura van Holstein, a PhD student in Biological Anthropology at the University of Cambridge, and her colleagues have proven Darwin right. According to a University of Cambridge report
, "her research could now be used to predict which species conservationists should focus on protecting to stop them becoming endangered or extinct":
A species is a group of animals that can interbreed freely amongst themselves. Some species contain subspecies – populations within a species that differ from each other by having different physical traits and their own breeding ranges. Northern giraffes have three subspecies that usually live in different locations to each other and red foxes have the most subspecies – 45 known varieties – spread all over the world. Humans have no subspecies.
van Holstein said: “We are standing on the shoulders of giants... My research investigating the relationship between species and the variety of subspecies proves that sub-species play a critical role in long-term evolutionary dynamics and in future evolution of species. And they always have, which is what Darwin suspected when he was defining what a species actually was.”
van Holstein’s research also proved that evolution happens differently in land mammals (terrestrial) and sea mammals and bats (non-terrestrial) because of differences in their habitats and differences in their ability to roam freely.
Here is the scientific paper: "Terrestrial habitats decouple the relationship between species and subspecies diversification in mammals" (The Royal Society)
image credit: Nordin Ćatić, University of Cambridge news release
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Thanks to a tweet by Ars Technica's John Timmer, I was introduced this morning to Gomez's Hamburger—a delightfully named astronomical feature about 900 lightyears away from Earth.
The name is funny. But what makes Gomez's Hamburger worth posting about here is that it gives you a glimpse of a process you've probably only read about before. Scientists think that planets form out of clouds of gas and dust circling a star. Over time, bits of dust clump together into larger objects, which in turn collide and smush into even larger objects. Eventually, instead of a star sitting in a dust cloud like Pigpen from Peanuts, you've got a classy, mature star orbited by a series of planets.
Gomez's Hamburger is most likely a young star sitting in a dust cloud. The dust is actually the meat in this sandwich. The "buns" are actually light reflecting off of the dust. Read the rest
Confused about what we do and don't know about the relationship between humans and Neanderthals? This video by Lynn Fellman will get you up-to-date on the basics—including some of the questions that haven't been answered yet. It doesn't cover everything, but it is a nice primer on recent research and how that research was done.
EDIT: Bad news: Autoplay continues to be the devil. The good news: If you go to Lynn Fellman's website to view the video there, it doesn't autoplay. So follow the link and enjoy.
Image: Neanderthal Silhouette, a Creative Commons Attribution (2.0) image from erix's photostream
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Humans and neanderthals: Getting it on, after all?
What Became of Neanderthals? We Ate ‘em, Made ‘em into Jewelry, Says Scientist
Hot human-on-neanderthal action: A scientific update
More on the sex lives of ancient humans
We didn’t kill our grandfather Read the rest