Worm brain sheds light on the evolution of the cerebral cortex

The last time humans and the marine ragworm Platynereis dumerilii shared a common ancestor was roughly 600 million years ago, according to scientists from the European Molecular Biology Laboratory in Heidelberg, Germany (EMBL). That is, researcher have discovered a true counterpart of the cerebral cortex, also called the pallium, in this relative of the earthworm. This finding, explained the scientists, could be the key to unraveling the evolution of this important area of the human (and all vertebrates) brain.

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From the Community: fish-mimicking octopuses, aquanauts and the evolution of ecology

An octopus that mimics toxic sea creatures, the tobacco plant sends out an SOS when attacked, the genetic differences between ant social castes, unusually high records of jellyfish swarms this summer and Simon Levin discusses the evolution of ecology and where it is headed next. Here are stories in ecology wrapping up the month of August.

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Flowers make it rain (and then some)

The Amazon rainforest—with its millions of creaking, chirping and buzzing insects, sticky frogs, vibrant birds, and unique fish—may owe its diversity primarily to flowers, said researchers from the University of Chicago. And, they say, just as flowering plants formed the building block of biodiversity in this region, their removal could result in a cascade of declining diversity.

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The sharp shooters of marine life

The archerfish’s long distance spitting can fire a bug off of a branch and send it down to the water’s surface, and the nearly-blind pistol shrimp uses its gigantic claw to stun its prey with a bubble nearly as hot as the Sun. However, if the archerfish didn’t have keen eyes enabling it to detect an insect against a vegetative background, and if the pistol shrimp lacked its protective eye covers, called orbital hoods, these animals might never have developed the ballistic mechanisms that characterize them.

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The phrenologist’s guide to ecological competence

Since Darwin, scientists have been theorizing as to why there is variation in brain size between species and individuals. Does a larger brain, in say humans, indicate advanced cognitive abilities and complex language processing? Or is a smaller brain, such as the Olive-backed thrush’s, adapted to weigh less to accommodate lengthy flights?

In psychology, the field of phrenology has generally been dissolved, and with it, the idea that variations in brain size could indicate differences in intelligence, creativity or personality between humans. In the field of biology, however, scientists are discovering that brain variation across species might actually be linked to ecological competence. In this case, ecological competence describes the efficiency of a species to engage in ecological processes—such as flexible foraging abilities or advanced spatial memory for migration.

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Antbird songs converge while other traits don’t

Convergent evolution of large functional traits is not uncommon in nature; consider that wings have evolved in several lineages of animals to broaden niches that animals can fill.  But more specific convergence, especially in sexual and territorial signals, is rare at best and stirs controversy in the scientific world. On the surface, it would seem that if two species converge in their signals, it would lead to crossbreeding and...

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Fungi turn ants into zombies. (need I say more?)

A stroma, or spore-releasing body, of a killer fungus grows out of the head of a victim ant. Image courtesy David Hughes and with thanks to Science News. As much as Hollywood might want you to think they exist, zombies are fictitious. But a study out today claims that actually, they kind of do exist — if your undead is an ant and your possessive reviving sorcerer a deadly and clever species of fungus. Imagine you’re a...

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Flu evolving in the human body ecosystem

The field of disease ecology is a fast-evolving one as ecologists realize more and more that the insides of animals and plants are really like small-scale ecosystems, encompassing the same rules as large-scale ecosystems, like species interactions, environmental variability and evolutionary change. Katia Koelle of Duke University gave a talk yesterday about evolution in the H3N2 virus — not to be confused with the H1N1 swine...

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