Evolution, the history of life Evolutionary scenarios are not frozen in time. Whether they analyze them in terms of geological periods or groups of species, scientists are constantly redefining their features. The helmets of the different species of insects called treehoppers take on a huge variety of shapes. First insects with three pairs of wings identified ----------------------------------------------------------------------------------------------- Treehoppers are insects with a protuberant head ornament, called helmet. The exact nature of this anatomical structure, which, depending on the species, can take the form of an ant in attack position, a dead leaf or a thorn, was until recently a subject for debate. When they examined the helmet through an electron microscope, entomologists realized that it was not merely a simple outgrowth of the insect’s shell. With muscles and a flexible membrane that allow it to be mobile, this dorsal appendage, attached to each side of the thorax by an articulation, actually displays all the anatomical features of a pair of wings. This is the first discovery of a change in an insect’s body plan through the addition of an evolutionary innovation. It gives the lie to the principle that insects never have more than two pairs of wings. According to a new study, it took less Nature May 2011 than two million years for reefs made by multicellular animals to reappear and diversify—instead of around ten million years as previously thought—in the aftermath of the Non-genetic heredity enters the evolutionary extinction that marked the end of the scene Paleozoic Era, 252.6 million years ago. -------------------------------------------- On the basis of several examples found in scientific literature, researchers have shown that it is the complexity of the interactions between the various inheritance systems, whether genetic or not, that generates the huge variety Human remains discovered in the of evolutionary processes. Their work suggests that non-genetic inheritance, Crimea have been dated to 32,000 such as epigenetic variation and ecological and cultural heritage, should be years ago. This makes them the oldest incorporated into ecological and evolutionary approaches, thus widening the direct evidence of human presence scope of the theory of evolution. Getting beyond the notion that everything in south-east Europe. is controlled by genetics could therefore lead to a deeper understanding of evolutionary sciences and biodiversity. -------------------------------------------- Nature Reviews Genetics July 2011 16 A year at CNRS 2011
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