After a few weeks working on a redesign of our site (click here for a list of changes), we return this week to our weekly science news update. The theme this week is evolution, and our update includes articles on plants and animals, and the evolution of our diet.
Science News for the Science Classroom
Fossilized Pigments in Ancient Marine Animals
For the first time ever, a Swedish-based lab has uncovered the pigmentation of three ancient marine species. After extracting melanin from the 55 million year old fossil of a leatherback turtle, a 85 million year old Mosasaur fossil and a 190 million year old Ichthyosaur fossil, the Swedish team found that all three ancient species were at least partially dark-colored.
While the Mosasaur and the ancient Leatherback turtle probably possessed a darker upper half and a lighter complexion on the underside of their bodies, a type of coloration common in modern fish known as “countershading”, at least some kinds of Ichthyosaur featured a solidly colored body, much like the modern sperm whale. This suggests that the Ichthyosaur was, like the sperm whale, a deep diving predator.
100 Million Year Old Flower Trapped in Amber
100 million years ago, in the late Cretaceous period, flowering plants were only just beginning to affect the biodiversity of Earth. Late last year, scientists discovered several members of one of these early flower species, Micropetasos burmensis, trapped in amber- one of which was in the process of undergoing sexual reproduction.
While flowering plants were only just beginning to develop symbiotic relationships with insects during this early stage of their evolution, the fossilized pollen trapped in amber most likely was transported by an early bee or wasp species.
Obesity Can’t be Blamed On Hunter-Gatherers
The “thrifty genome hypothesis” theorizes that ancient hunter-gatherers adapted to more readily develop fat stores in order to survive frequent famines. With the realities of the overabundance of food in the modern western world, the hypothesis is often cited as major reason behind today’s obesity.
Yet this theory is rapidly being proven wrong. A new study of hunter-gatherer cultures shows that hunter-gatherers experience an equal or even lesser amount of famine compared to agricultural societies. In short, it is today’s fast food and lack of exercise that remains responsible for obesity, rather than some inherent genetic disposition.
Ancient Fish Had Hind Legs
Although fossils have shown that the first animals who made the transition from water to land possessed front limbs, hind legs have long been believed to have evolved only after early fish and amphibians had fully begun to adapt to land. Tiktaalik roseae proves this idea wrong.
While clearly a fish, Tiktaalik roseae, which resembled a cross between a fish and a crocodile and grew to up to 9 feet long, possessed a tetrapod-like structure, with a mobile neck, durable ribcage, and most importantly, strong hind legs. With the discovery of Tikaalik roseae, scientists are beginning to hypothesize that tetrapods first evolved in the ocean before moving onto land.
Our newest video explores the properties of water, with a focus on the importance of hydrogen bonds. If you are looking for tutorial videos, or a quick chemistry reviews for your classes, then check out our YouTube site.
YouTube Link: http://youtu.be/aVmU3CLxvgU