Just as the seasons change, bringing rain with them, so too does scientific learning fall upon us. This week‘s scientific highlights include new insights into European Neanderthal populations, assumptions on one of Leonardo da Vinci‘s hypotheses proving false and a new phase for the Curiosity Rover.
NASA’s Curiosity Rover enters new phase of exploration
Three billion years ago, during Mars’ last wet phase, debris flows severely eroded Mount Sharp. It is believed that the muddy landslides that formed the Gediz Vallis River show evidence of liquid water on Mars.
Not only is this feat significant because of the arduous journey Curiosity endured to climb over Mount Sharp, but researchers discovered that the rocks around the ridge likely came from higher up the mountain and were washed down in the debris flow.
Curiosity is part of NASA’s Mars Science Laboratory mission and was launched on Nov. 26, 2011, landing nearly a year later on Aug. 6, 2012. The main purpose of the rover was to determine whether Mars ever had the right circumstances and environment to support microbe life. Curiosity is well-traveled, having seen several monumental Martian landmarks, such as the Gale Crater, and has provided further evidence of water on Mars.
Last month marked the rover’s 11th year on Mars. Now, Curiosity will embark on a new mission to find a path up a channel at the top of the ridge to aid experts in understanding water flow patterns on Mount Sharp.
New understandings of Iberian Neanderthal bones
A multidisciplinary team of experts has found new insights into Iberian Neanderthal populations. They investigated a box of Neanderthal bones and artifacts that was initially donated by amateur paleontologist Miguel Aznar to the Archaeology Museum of Catalonia in 1986.
The box contained fifty-three Neanderthal bones, likely belonging to three individuals, an adult woman and two children. The experts utilized radiocarbon dating experiments to mark these bones as roughly fifty thousand years old.
To learn more about the bones, the experts visited Cova Simanya, the excavation site where Aznar first retrieved the remains. In their own investigation, they found a tooth that matched one of the individuals in the box. These triumphs will aid experts’ understanding of the evolution of Neanderthals, especially as it pertains to their development on the Iberian Peninsula. These developments are significant as Neanderthals are the first known extinct relative to modern humans and provide us with a point of reference to describe our own evolution.
Unfortunately, the team failed to extract DNA from the bones, which limits the find’s utility in understanding Neanderthal genetic diversity. However, it remains a valuable addition to our understanding of evolutionary history.
Long-Standing assumptions on Da Vinci’s “Rule of Trees” overturned by new insights
The “Rule of Trees”, proposed by Leonardo da Vinci, was recently disproven by scientists at the Bangor University in the UK and the Swedish University of Agricultural Sciences (SLU).
Da Vinci theorized that a tree grows such that the combined cross-sectional area of all the branches of a tree is preserved across the entire height of the plant. While Da Vinci used this theory as a helpful metric for artistic purposes, it was presumed to be true for tree vascular systems, stating that the individual sizes of channels that transport water and nutrients decrease the same way the branches narrow.
However, on a microscopic level, the researchers learned that vascular channels widen as branches thin towards the very tops of trees. The team used a model called Metabolic scaling theory to analyze a tree's vascular architecture, focusing on the hydraulic resistance — resistance to liquid flow along a given path — to locate a point in the vascular system that required a vascular width greater than that predicted by the “Rule of Trees.” The vascular channels need to maintain some amount of volume to maintain hydraulic resistance. A plant reduces in volume as it reaches extremities, so to maintain that pressure, capillaries take up more space.
Stuart Sopp, one of the scientists involved in the project, mentions that their new research could be used to estimate carbon volume in large forest areas to provide a metric for accurately measuring carbon concentration captured by trees on a global scale.
Silkworms offer a sustainable alternative to synthetic fibers
Nylon and Kevlar have become staples of the synthetic fiber industry, yet have been heavily criticized by sustainable materials movements across the past two decades. Researchers from Southwest University and Donghua University in China reported that CRISPR-modified silkworms may provide a more carbon-neutral alternative to these materials.
Though several efforts have been made to develop high-tensile fibers that parallel Kevlar’s toughness and Nylon’s strength, none have come as close to providing a solution as spider silk. The current issue with spider silk, however, is the lack of knowledge regarding its production and thus its inability to be commercialized on a large scale.
This CRISPR silkworm project aimed to provide a microscopic model for spider silk extraction. After noting the critical characteristics of spider silk and the key differences between silkworm silk and spider silk, the university experts employed CRISPR techniques to create silkworms that could produce spider silk. The modified silk is six times tougher than Kevlar and has higher natural tensile strength than nylon. The experts hope that with further efforts, silkworm-produced spider silk can be a low-cost, large-scale alternative to synthetic fibers on the market.