Tag: evolution

Biodiversity Evolution

Biodiversity alters strategies of bacterial evolution

a paper published in Nature found that when a bacterial species resides in even a very simple ecological community — one that includes just a few other kinds of microbes — it evolves very different defense strategies against a predatory bacteriophage virus than it does when it’s left alone with the phage. The research is expanding these ideas into the context of the microbiome, where bacteria exist alongside loads of other species. The finding not only elevates the value of biodiversity as an evolutionary factor in its own right, but suggests that some earlier conclusions about the behaviors and capabilities of microorganisms, drawn from laboratory studies of species in isolation, may be seriously incomplete. It also sounds a note of caution about some contemplated strategies for beating drug resistance in bacteria.

Human Diversity

Nothing we are going to learn will diminish our common humanity. Nothing we learn will justify rank-ordering human groups from superior to inferior — the bundles of qualities that make us human are far too complicated for that. Nothing we learn will lend itself to genetic determinism. We live our lives with an abundance of unpredictability, both genetic and environmental

Steppingstone principle

The steppingstone principle goes beyond traditional evolutionary approaches. Instead of optimizing for a specific goal, it embraces creative exploration of all possible solutions. By doing so, it has paid off with groundbreaking results. 1 system based on the steppingstone principle mastered 2 video games that had stumped popular machine learning methods. DeepMind reported success in combining deep learning with the evolution of a diverse population of solutions. The steppingstone’s potential can be seen by analogy with biological evolution. In nature, the tree of life has no overarching goal, and features used for 1 function might find themselves enlisted for something completely different. Feathers likely evolved for insulation and only later became handy for flight. If we want algorithms that can navigate the physical and social world as easily as we can — or better! — we need to imitate nature’s tactics. Instead of hard-coding the rules of reasoning, or having computers learn to score highly on specific performance metrics, we must let a population of solutions blossom. Make them prioritize novelty or interestingness instead of the ability to walk or talk. They may discover an indirect path, a set of steppingstones, and wind up walking and talking better than if they’d sought those skills directly.

Out of Africa 2.5 ma ago?

The general consensus for decades has been that Homo erectus—an upright, long-legged species—was among the first hominins (or species closely related to modern humans) to leave Africa. Scientists presume members of this species traveled through the natural corridor of the Levant, a region along the eastern edge of the Mediterranean, around 2 ma ago. Scardia’s study suggests a far earlier exit. It proposes that hominins capable of tool creation may have been on the doorstep of Asia some 500 ka earlier.

Modeling Evolution

Barricelli programmed some of the earliest computer algorithms that resemble real-life processes: a subdivision of what we now call “artificial life,” which seeks to simulate living systems—evolution, adaptation, ecology—in computers. Barricelli presented a bold challenge to the standard Darwinian model of evolution by competition by demonstrating that organisms evolved by symbiosis and cooperation. Until his death in 1993, Barricelli floated between biological and mathematical sciences, questioning doctrine, not quite fitting in. “He was a brilliant, eccentric genius”

Lamarckism

Once a modern heresy, non-Darwinian inheritance, aka Lamarkism, increasing can be shown to sometimes happen in nature.

The traditional concept that heritability occurs exclusively from the transfer of germline-restricted genetics is being challenged by the increasing accumulation of evidence confirming the existence of experience-dependent transgenerational inheritance. Transgenerational inheritance is emerging as a powerful mechanism for robustly transmitting phenotypic adaptations to offspring. However, questions remain unanswered as to how this heritable information is passed from somatic cells. Previous studies have implicated the critical involvement of RNA in heritable transgenerational effects and the high degree of mobility and genomic impact of RNAs in all organisms is an attractive model for the efficient transfer of genetic information. Here we show, for the first time, robust transport of RNA from the brain of an adult male mouse to sperm, and subsequently to offspring. Our observation of heritable genetic information originating from a somatic tissue may reveal a mechanism for how transgenerational effects are transmitted to offspring.

change.org parody

A neural net trained on change.org tries to write its own petitions, eg “Help Bring Climate Change to the Philippines!” and “Donald Trump: Change the name of the National Anthem to be called the ‘Fiery Gator’”

stories about sexual selection (like “women are naturally attracted to dominant-looking men, because throughout evolution they were better able to provide”) are meaningless, because for most of human history women did not choose their own mates, and so women are unlikely to have strong biologically-ingrained mate preferences.

Dog eye evolution

dogs’ faces are structured for complex expression in a way that wolves’ aren’t, thanks to a special pair of muscles framing their eyes. These muscles are responsible for that “adopt me” look that dogs can pull by raising their inner eyebrows. It’s the first biological evidence scientists have found that domesticated dogs might have evolved a specialized ability used expressly to communicate better with humans

Cell Compartmentalization

When compartmentalization was thought of as a singular feature of eukaryotes, experts were often forced to speculate about how it came about, what the biophysical constraints were, and what selective advantages it might have. “That’s where these prokaryotes become really interesting. If they show some features that are even mildly similar to what we see in eukaryotes, it allows us to broaden the question and attack from a different angle: Under what conditions might compartmentation provide some benefit? Or is it just the case that there’s no benefit whatsoever?” The bacterial cases “suggest that there are multiple ways to do this, and that there could be a strong evolutionary advantage to doing so.” That certainly seems to have been the case with energy production: The independent evolution of anammoxosomes in some kinds of bacteria and mitochondria in eukaryotes signify that “the compartmentalization of energy metabolism is beneficial to the cell. You see a trend in both prokaryotes and eukaryotes to compartmentalize certain traits or certain functions in order to better control them.”

2021-01-10: Biomolecular condensates are an emerging type of membrane-less organelle, and adding a lot to our understanding of cell compartmentalization.

Inside cells, droplets of biomolecules called condensates merge, divide and dissolve. Their dance may regulate vital processes. Biomolecular Condensates may explain the speed of many cellular processes. “The key thing about a condensate — it’s not like a factory; it’s more like a flash mob. You turn on the radio, and everyone comes together, and then you turn it off and everyone disappears”


2022-11-02: Condensates are getting more refined experiments to figure out what’s going on

After an initial rush to document the phenomenon in every nook and cranny of the cell, scientists are beginning to ask more detailed questions. They want to know what these globules are doing, how they form and, importantly, how to prove that these biomolecular condensates are really as widespread and essential to the cell as many reports have claimed. Researchers are also responding to critics who have questioned the accuracy of some descriptions of phase separation in cells, arguing that other forces besides phase separation could have created droplets.
Inside the condensates, enzymatic reactions were 36x faster. Condensates gave the process extra structure: they helped to organize the enzymes spatially, providing a molecular ‘scaffold’ so that they could more easily partner with their reactants. “You get this combined effect of increasing efficiency and increasing concentration”
Some in the community have sought to inject precision into the field and guide researchers in finding out whether a blob forms through phase separation or in some other way. Despite the debates in academia, drug hunters are embracing the concept. Most companies interested in phase separation are prioritizing drug development for cancer and neurological disorders, 2 disease classes frequently linked to condensates that have gone awry.

Do Traditions still matter?

1 way to ensure survival is high-fidelity adherence to traditions + ensuring that the inherited ancestral environment/context is more or less maintained. Adhering to ancient traditions when the context is rapidly changing is a recipe for disaster. No point in mastering seal-hunting if there ain’t no more seals. No point in mastering the manners of being a courtier if there ain’t no more royal court. Etc. And the problem is that, in the modern world, we can’t simply all mutually agree to stop changing our context so that our traditions will continue to function as before because it is no longer under our control.