Core Insights - The Cambrian explosion represents a critical milestone in the evolutionary history of life on Earth, characterized by a rapid emergence of nearly all existing animal phyla [1] - The driving mechanisms behind the pulsed oxygenation during this period remain unclear, despite evidence linking it to periodic atmospheric and shallow marine oxygenation [1] Group 1: Research Findings - A research team from the Nanjing Institute of Geology and Palaeontology has revealed that long-term orbital changes may be the driving force behind the pulsed oxygenation process during the Cambrian period [2] - Previous studies indicated that marine animal diversity exhibited periodic changes over a timescale of approximately 2 to 3 million years, correlating with fluctuations in seawater carbon and sulfur isotopes [2] - The research suggests that global organic carbon and pyrite burial undergo periodic changes, affecting atmospheric and shallow marine oxygen levels, which in turn influence early marine animal evolution [2] Group 2: Methodology and Results - The study conducted spectral analysis on published carbon-sulfur isotope records from the early Cambrian, identifying long-period changes of 1.2 million, 2.6 million, and 4.5 million years that align with long-period orbital changes [3] - Numerical simulations using a deep-time Earth system box model (SCION) demonstrated that climate changes driven by orbital factors can replicate the synchronous periodic variations in seawater carbon-sulfur isotopes, supporting the hypothesis [3] - Sensitivity experiments indicated that low sulfate concentrations in the ocean may amplify the response of the carbon-sulfur-oxygen biogeochemical cycle to nutrient inputs driven by orbital changes, highlighting a critical shortcoming in the stability of the Cambrian Earth system [3]

中新网西安9月29日电 (记者 阿琳娜)从蜗牛的壳、螃蟹的甲，到人类的骨头——动物的"硬骨架"是怎么 来的？地球上的动物骨骼是如何长出来的？ 西北大学29日对外公布，该校张志飞教授指导博士研究生胡亚洲及团队成员，联合课题组外专Timothy Topper和Luke Strotz教授及中国科学院南京地质古生物研究所李国祥研究员与潘兵博士，对产自中国华 北板块寒武纪早期猴家山组的开腔骨骨片开展了系统研究，成果以亮点封面论文发表在美国地质学会著 名期刊——GEOLOGY。团队发现，5亿年前的化石里藏着动物最早由上皮组织控制骨骼生长的证据， 刷新了人类对早期动物的认知。 开腔骨骨片上多边形有机质框架结构包覆在磷酸盐化内核上，同时被磷灰石质外模包围，透射电镜能谱 分析揭示多边形结构以黏土矿物保存。西北大学供图 据介绍，动物是显生宙地球上的创新主角。珊瑚、腕足动物、软体动物和管栖环节动物(原口动物)等往 往具有防御用外骨骼，棘皮动物和各种脊椎动物等(后口动物)往往具有支撑身体的内骨骼。现代生物学 的研究认为原口动物和后口动物骨骼的矿化机制和生理过程可能不同，但均是在上皮组织或者结缔组织 控制下形成的矿化结构。那么，现如今 ...

Core Viewpoint - The research highlights the mitochondrial origins of sleep pressure, suggesting that sleep is not merely a resting state for the brain but a crucial maintenance process for the body's energy supply system [4][11]. Group 1: Research Findings - A study published in Nature reveals that sleep pressure arises from ATP surplus in specific brain cells, indicating a physical basis for sleep drive [4]. - The research team conducted a comparative analysis of the single-cell transcriptome characteristics of fruit flies under sufficient sleep and sleep deprivation, finding significant gene expression changes related to mitochondrial respiration and ATP synthesis in sleep-deprived flies [6][11]. - Mitochondrial fragmentation and increased mitochondrial-autophagy were observed in affected neurons, which could be reversed by restoring sleep [6][9]. Group 2: Mechanisms of Sleep Regulation - The study found that mitochondrial dynamics (fusion and fission) significantly influence the excitability of sleep-regulating neurons, thereby affecting sleep demand [9][11]. - During wakefulness, especially under sleep deprivation, the activity of these neurons is suppressed, leading to increased ATP concentration due to reduced consumption [9]. - Manipulating mitochondrial dynamics can either enhance or reduce sleep duration, indicating a direct link between mitochondrial function and sleep regulation [9][11]. Group 3: Implications and Future Directions - The findings provide insights into the relationship between metabolism, sleep, and lifespan, suggesting that sleep may be an unavoidable byproduct of aerobic metabolism, similar to aging [10][11]. - The research opens new avenues for understanding sleep disorders and their potential interventions by targeting mitochondrial function in specific neurons [11].

Core Viewpoint - The establishment of the "golden nail" in Guizhou, China, represents a significant advancement in global geological standards, providing a precise reference point for defining geological time scales and enhancing China's influence in earth sciences [3][4][12]. Group 1: Definition and Importance of "Golden Nails" - "Golden nails" are not literal nails but refer to globally recognized geological markers that define the boundaries of geological time units, serving as a standard for stratigraphic classification [4]. - The concept of "golden nails" addresses the historical lack of a unified standard for geological time scales, which has led to significant discrepancies in stratigraphic classification across different countries [4][6]. Group 2: The Significance of the Guizhou "Golden Nail" - The "golden nail" in Guizhou, set to be established in June 2025, is the 69th globally and the 11th in China, recognized for its exceptional geological and paleontological conditions [6][9]. - The site in Guizhou was selected due to its rich fossil record, accessibility, and long-term research conducted by local experts, meeting the stringent criteria set by the International Stratigraphic Commission [6][7]. Group 3: Geological Insights from the "Golden Nail" - The Guizhou "golden nail" will help define the Cambrian period's third system and fifth stage by identifying the first appearance of specific trilobite fossils, which are crucial for understanding geological events from 506 million years ago [9][10]. - The site provides vital evidence for the Cambrian explosion, a significant evolutionary event characterized by a rapid increase in biodiversity [10]. Group 4: Implications for China's Geological Research - The establishment of 11 "golden nails" in China underscores the country's growing capabilities in geological research and its enhanced standing in the global scientific community [12]. - Protecting these geological sites is essential, as they face threats from natural erosion, geological hazards, and human activities, necessitating a collaborative effort for their preservation [12].

Core Insights - The research team led by Professor Zhang Zhifei from Northwest University has successfully uncovered the mystery of Cambrian small shell fossil preservation after seven years of effort [1][2] - The study reveals that small shell fossils can be preserved through various methods, including phosphatization, dolomitization, and glauconitization, with phosphatization not being the dominant preservation method in the late Cambrian [1][2] Research Findings - The research involved the acid treatment of nearly 8 tons of Cambrian carbonate rock samples, resulting in the successful extraction of over 35,000 small shell fossils [2] - Advanced analytical techniques such as micro-X-ray fluorescence spectroscopy and scanning electron microscopy were employed to discover the diverse preservation methods of small shell fossils [2] - The study confirms that phosphatic deposition is not the primary factor controlling the production of high-quality small shell fossils, suggesting alternative preservation mechanisms [2] Implications - This research provides a new perspective for the search and interpretation of early life fossils, demonstrating that life evolution evidence can be preserved even under unfavorable conditions lacking phosphates [2] - The findings are expected to significantly advance the understanding of the mineralization mechanisms of animal skeletons and the early evolutionary processes [2]

Core Viewpoint - The article emphasizes the importance of biodiversity and the urgent need for its protection, highlighting the interconnectedness of human fate and the survival of diverse species on Earth [2][7]. Group 1: Evolution of Life's Colors - The early Earth was predominantly brown, gray, and green, but has evolved into a vibrant world filled with colors due to various evolutionary processes [2][5]. - The evolution of vision played a crucial role in this color explosion, with the development of trichromatic vision around 541 million years ago coinciding with the Cambrian explosion, allowing organisms to better navigate their environments [4][5]. Group 2: Color Revolution in Flora and Fauna - The first color revolution was led by plants, which evolved colorful fruits and flowers approximately 300 to 377 million years ago to attract animals for seed dispersal and pollination [5][6]. - Animal color evolution began around 140 million years ago, with bright colors serving as survival signals for mating, deterring predators, or establishing dominance [5][6]. Group 3: Genetic Diversity and Endangered Species - The loss of genetic diversity is accelerating globally, particularly among birds and mammals, due to habitat destruction, disease, and human activities [10][11]. - A study involving 57 scientists from 20 countries assessed genetic diversity changes in 622 species over 30 years, revealing alarming trends but also highlighting the potential for effective conservation strategies [10][11]. Group 4: Strategies for Conservation - Five key strategies to maintain or restore genetic diversity in endangered species include: 1. **Population Supplementation**: Introducing new individuals to existing populations has shown significant positive effects on genetic diversity, especially in birds [11]. 2. **Population Control**: Removing individuals can sometimes enhance population health by reducing resource competition [12]. 3. **Ecosystem Restoration**: Restoring habitats can help maintain and even increase genetic diversity over time [13]. 4. **Control of Invasive Species**: Managing invasive species can aid in the recovery of endangered populations by reducing competition [14]. 5. **Conservation Translocation**: Establishing populations in new areas or reintroducing them to former habitats can be effective if managed properly [15]. Group 5: Individual Actions for Biodiversity - Individuals can contribute to biodiversity conservation through simple actions such as creating diverse gardens, protecting traditional crop varieties, participating in community conservation efforts, and being responsible in nature [17][18].