Evolution — Page 2

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.

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.

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.

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.

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.

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…

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…

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…

The intersection of evolution and ecology has risen to become a prominent subfield in both disciplines in recent years, with scientists exploring more and more how interactions among organisms can shape evolution at the population and even species level.  In the May issue of the journal Ecology, Ethan Temeles of Amherst College explores a fascinating relationship between the males and…

Climate change has the potential to not only increase average temperatures around the world, but also to increase the likelihood and severity of now-rare temperature events, like heat waves.  The fate of many animal populations, therefore, can hinge on their ability to tolerate (relative) extreme heat. In the April issue of Functional Ecology, scientists explore the possible responses of animal…

Cold-blooded animals don’t produce their own heat, and thus they must sunbathe, basking in the sun’s rays to raise their body temperatures so they have eonugh energy to  go about their business. But for some ectotherms, the sun isn’t just a source of heat.  A new study shows that in the panther chameleon, native to Madagascar, basking behavior also controls…

Evolutionary biologists agree that the natural environment shapes the evolution of life. A study published in Nature today, however, finds that the evolution of a species can also have big impacts on the surrounding environment. Threespine stickleback are famous as an example of rapid, adaptive radiation. These small freshwater fish have evolved in the lakes of British Columbia to have…