A new suggestion that complexity increases over time, not just in living organisms but in the nonliving world, promises to rewrite notions of time and evolution.
Category: evolution
In a recent study, researchers gained new insight into the lives of bacteria that survive by grouping together as if they were a multicellular organism. The organisms in the study are the only bacteria known to do this in this way, and studying them could help astrobiologists explain important steps in the evolution of life on Earth.
The work is published in the journal PLOS Biology.
The organisms in the study are known as multicellular magnetotactic bacteria (MMB). Being magnetotactic means that MMB are part of a select group of bacteria that orient their movement based on Earth’s magnetic field using tiny “compass needles” in their cells. As if that weren’t special enough, MMB also live bunched up in collections of cells that are considered by some scientists to exhibit “obligate” multicellularity, the trait on which the new study is focused.
Some stars in our galaxy pulse like musical instruments, and scientists have found a way to listen in. These rhythmic starquakes, like vibrations in a string or drum, reveal vital clues about a star’s age, composition, and life cycle.
By studying these “melodies” in a star cluster called M67—whose stars are like solar siblings—researchers uncovered a strange pause in stellar evolution called the “plateau.” This discovery helps pinpoint stellar ages with remarkable precision, bringing us closer to understanding how stars, and ultimately our galaxy, have evolved.
Celestial Music: Listening to Starquakes.
At the viral chatter stage of an outbreak, pathogens are just starting to infect people in sporadic bursts. It’s a sign that a pandemic may be on the horizon.
Millions of years before the asteroid impact that ended the reign of the dinosaurs, mammals were already beginning to shift from tree-dwelling to ground-based lifestyles.
A groundbreaking study uncovered this evolutionary trend by analyzing tiny limb bone fragments from marsupials and placental mammals in Western North America. These subtle fossil clues reveal that mammals may have been responding to a changing world, especially the spread of flowering plants that transformed habitats on the ground. Surprisingly, this terrestrial transition appears to have played a bigger role in mammalian evolution than direct interactions with dinosaurs.
Early Ground-Dwellers Before Dinosaurs’ Demise.
1999/ 2000 documentary 56 minutes. Primal Eye/ Median Vision Theory of the early evolution of self referential consciousness and dreaming. Dir…
Humans like to think that being multicellular (and bigger) is a definite advantage, even though 80% of life on Earth consists of single-celled organisms—some thriving in conditions lethal to any beast.
In fact, why and how multicellular life evolved has long puzzled biologists. The first known instance of multicellularity was about 2.5 billion years ago, when marine cells (cyanobacteria) hooked up to form filamentous colonies. How this transition occurred and the benefits it accrued to the cells, though, is less than clear.
A study originating from the Marine Biological Laboratory (MBL) presents a striking example of cooperative organization among cells as a potential force in the evolution of multicellular life. Based on the fluid dynamics of cooperative feeding by Stentor, a relatively giant unicellular organism, the report is published in Nature Physics.
Researchers from the Institute of Solid State Physics, the Hefei Institutes of Physical Science of the Chinese Academy of Sciences, in collaboration with Southwest Jiaotong University, have combined high-pressure electrical transport experiments, high-pressure Raman spectroscopy, and first-principles calculations to reveal the structural phase transition behavior of hafnium oxide (HfO2) under high pressure and its evolution mechanism in electrical properties.
The paper is published in the journal Physical Review B.
“This study resolves the previous controversies regarding the phase transitions of HfO2 in the low-pressure region,” said Pan Xiaomei, a member of the team.
Every time the temperature drops, a cloud passes overhead, or the sun sets, a plant makes a choice: Keep its microscopic pores, called stomata, open to absorb carbon dioxide and continue photosynthesizing or close them to protect its precious stores of water. That capacity to open and close pores requires the plant to respond to subtle environmental changes by adjusting the pressure within the cells of the stomata—a complex ability that plants evolved over hundreds of millions of years.
An interdisciplinary team of biologists, physicists, and engineers, led by researchers at the Yale School of the Environment, has developed a method to observe those pressure changes. The new approach, detailed in a study published in PNAS, vastly expands the rate at which—and the number of species from which—scientists can take measurements, opening up new possibilities for research on plant evolution and physiology with valuable applications for improving water efficiency, the researchers said.
“Almost every single land plant is using this principle of internal pressure in order to grow, reproduce, and do everything a plant does, but we previously had basically no access to this measurement,” said Craig Brodersen, the Howard and Maryam Newman Professor of Plant Physiological Ecology and the lead author of the study.
You may have heard of the fantastic-sounding “dark side of the genome.” This poorly studied fraction of DNA, known as heterochromatin, makes up around half of your genetic material, and scientists are now starting to unravel its role in your cells.
For more than 50 years, scientists have puzzled over the genetic material contained in this “dark DNA.” But there’s a growing body of evidence showing that its proper functioning is critical for maintaining cells in a healthy state. Heterochromatin contains tens of thousands of units of dangerous DNA, known as “transposable elements” (or TEs). TEs remain silently “buried” in heterochromatin in normal cells—but under many pathological conditions they can “wake up” and occasionally even “jump” into our regular genetic code.
And if that change benefits a cell? How wonderful! Transposable elements have been co-opted for new purposes through evolutionary history—for instance the RAG genes in immune cells and the genes required for driving the development of the placenta and mammalian evolution have been derived from TEs.