Evolution

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Category archives for Evolution

Drifted Apart, Crammed Together

As organisms spread into new habitats, they diverge and differentiate to best adapt to their surroundings. But when separated species exploit similar niches, their body plans begin to converge, and they end up looking a lot like each other. Such is the case with Beaked Sea Snakes, uber-venomous consumers of spiny catfish and blowfish, long…

Animal Bodies Rearranged

On Pharyngula, PZ Myers considers a computer model which posits that bones are simply exoskeletons turned inside-out. Myers writes “We know from the homology of the patterning molecules involved that vertebrates and invertebrates are upside-down relative to each other, so at some point an ancestor flipped.” Such major differences in body plan arise during embryonic…

Divergent & Convergent Evolution

On ERV, Abbie Smith reports that scientists have discovered an entirely new branch of viruses in the boiling acid pools of Yellowstone National Park. By analyzing RNA segments from the pools, researchers inferred the existence of positive-strand RNA viruses with unknown genetic configurations. Smith writes, “These viruses are not just kinda new. They are really really different from the RNA viruses…

Anticlimactic Research

A new paper published in the journal Animal Behavior tackles the origin of the female orgasm—does it have gender-specific advantages, or is it merely a byproduct of male adaptations? Having polled 10,000 twins about their orgasmic tendencies, researchers found “no significant correlation between opposite-sex twins and siblings” and therefore concluded that “selection pressures on male…

Evidence, Layer by Layer

Evidence that life on Earth is very old (and of humble origin) continues to accrue, but some beliefs are insurmountable. On EvolutionBlog, Jason Rosenhouse refutes the argument that the evolution of complex molecules and organisms is highly improbable. He notes that if we “imagine evolution proceeding by selecting genotypes entirely at random, then the probability…

Winners

On Dean’s Corner, Jeffrey Toney reports the winners of Google’s first Science Fair, and in all age groups the winner was a girl. They researched some very challenging and relevant topics: Lauren “studied the effect of different marinades on the level of potentially harmful carcinogens in grilled chicken,” Naomi “endeavored to prove that making changes…

The science song is a strange beast; people have surely converted information to rhythms or rhymes as a mnemonic device for millennia, though the idea of “educational music” as a genre has only recently crystallized. Its target audience has oscillated since then; while Tom Lehrer was playing for adults in the 50s and 60s, a…

Chromosomes, X and Y

On Neurotopia, Scicurious offers a refresher course on mitosis. This vital process occurs every time a cell divides, as centrosomes pull apart replicated chromosomes with microtubules. Normal cell mechanics limit this “molecular tug of war” to about 50 iterations, meaning we can’t keep splitting chromosomes forever. But we can use meiosis make some babies. On…

Epochs Underfoot

Fossils offer a rare glimpse into the past, as lifeforms we could scarcely imagine are preserved long after their day in the sun. But fossilization requires very specific conditions, and few things that die are turned to stone. On Living the Scientific Life, GrrlScientist presents Haplocheirus, a theropod with “three toes, a birdlike keel-shaped chest…

Cause and Effect

Evolutionary change responds to all kinds of pressures, and sometimes, the results can be surprising. On Gene Expression, Razib Khan challenges the idea that human evolution has stopped since “the vast majority of humans reach the age of potential reproduction.” He explains that differential mortality is not a precondition for natural selection, and supports his…