Evolution’s Random Paths Lead to One Place
A massive statistical study suggests that the final evolutionary outcome — fitness — is predictable.
In his fourth-floor lab at Harvard University, Michael Desai has created hundreds of identical worlds in order to watch evolution at work. Each of his meticulously controlled environments is home to a separate strain of baker’s yeast. Every 12 hours, Desai’s robot assistants pluck out the fastest-growing yeast in each world — selecting the fittest to live on — and discard the rest. Desai then monitors the strains as they evolve over the course of 500 generations. His experiment, which other scientists say is unprecedented in scale, seeks to gain insight into a question that has long bedeviled biologists: If we could start the world over again, would life evolve the same way? Many biologists argue that it would not, that chance mutations early in the evolutionary journey of a species will profoundly influence its fate. “If you replay the tape of life, you might have one initial mutation that takes you in a totally different direction,” Desai said, paraphrasing an idea first put forth by the biologist Stephen Jay Gould in the 1980s. Desai’s yeast cells call this belief into question. According to results published in Science in June, all of Desai’s yeast varieties arrived at roughly the same evolutionary endpoint (as measured by their ability to grow under specific lab conditions) regardless of which precise genetic path each strain took. It’s as if 100 New York City taxis agreed to take separate highways in a race to the Pacific Ocean, and 50 hours later they all converged at the Santa Monica pier. The findings also suggest a disconnect between evolution at the genetic level and at the level of the whole organism. Genetic mutations occur mostly at random, yet the sum of these aimless changes somehow creates a predictable pattern. The distinction could prove valuable, as much genetics research has focused on the impact of mutations in individual genes. For example, researchers often ask how a single mutation might affect a microbe’s tolerance for toxins, or a human’s risk for a disease. But if Desai’s findings hold true in other organisms, they could suggest that it’s equally important to examine how large numbers of individual genetic changes work in concert over time. “There’s a kind of tension in evolutionary biology between thinking about individual genes and the potential for evolution to change the whole organism,” said Michael Travisano, a biologist at the University of Minnesota. “All of biology has been focused on the importance of individual genes for the last 30 years, but the big take-home message of this study is that’s not necessarily important.” (via Yeast Study Suggests Genetics Are Random but Evolution Is Not | Simons Foundation)
SHARKS and TROPHIC CASCADES
What Happens When Sharks Disappear?
Infographics by Lily Williams
Even worse: Humboldt squid will overpopulate. And they learn what to eat through trial and error. They are even known to attack and seriously harm divers. [x]
Protect your Ocean.
sharks are fucking important
There’s a reason Hi-Fructose keeps tabs on Tokyo artist Shohei (aka Hakuchi) Otomo(featured in Hi-Fructose Vol. 20). The only son of great manga artist Katsuhiro Otomo, the acclaimed writer and director of the anime cult classic Akira, Hakuchi carries on his father’s legacy with his own graphic illustrations that combine Japanese iconography with a dark, retro-punk edge and a healthy dose of sardonic humor. Read more on Hi-Fructose.
The Adventures of Rocket and Groot!
Did some work on a new pen over the weekend! This is cute Groot growing a white flower for you! ;) See more at my etsy shop.
another shameless plug!
Yay! Watercolors. Always good to change it up once in a while.
Here are some XAILORS for youz!!
Mapping the Light of the Cosmos
Figuring out what the structure of the universe is surprisingly hard. Most of the matter that makes up the cosmos is totally dark, and much of what is left is in tiny, dim galaxies that are virtually impossible to detect.
Image: The first image above shows one possible scenario for the distribution of light in the cosmos. Credit: Andrew Pontzen/Fabio Governato
This image shows a computer simulation of one possible scenario for the large-scale distribution of light sources in the universe. The details of how light (and hence galaxies and quasars) is distributed through the cosmos is still not a settled question – in particular, the relative contributions of (faint but numerous) galaxies and (bright but rare) quasars is unknown.
(New research from UCL cosmologists published last week shows how we should be able to find out soon.)
However, astronomers know that on the largest scales, the universe is structured as a vast web made up of filaments and clusters of galaxies, gas and dark matter separated by huge, dark voids. Observational astronomy is making strides forward in mapping out these structures in gas and light, but the smallest galaxies – less than a pixel across in the image above – might never be seen directly because they are simply too faint.
A Hubble image of a nearby faint dwarf galaxy (bottom image) shows the challenge involved in observing these objects even when they are in our galaxy’s vicinity.
These computer models are one way of trying to extrapolate from what we know to what is really there. New research from UCL now shows how we can also use future observations of gas to find out more about this elusive population of tiny galaxies.
This simulated image shows the distribution of light in an area of space over 50 million light-years across. The simulation was created by Andrew Pontzen of UCL and Fabio Governato of the University of Washington.
An animated chart of 42 butterflies
by Eleanor Lutz