Reference Terms
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Animal shell
A shell is a hard, rigid outer layer, which has evolved in a very wide variety of different animals, including mollusks, sea urchins, crustaceans, turtles and tortoises, armadillos, etc. Scientific names for this type of structure include exoskeleton, test, carapace, and peltidium.
The shells that are perhaps most familiar and most commonly encountered, both in the wild and for sale as decorative objects, are seashells, more precisely, the external shells of marine mollusks. These are usually primarily composed of calcium carbonate, in the form of calcite or aragonite crystallised out in an organic matrix. Calcium carbonate in mollusc shells can take different crystalline forms, one being nacre otherwise known as mother of pearl.
Other kinds of animal shells are made from chitin, bone and cartilage, or silica.
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Plants & Animals News
December 12, 2025
Dec. 12, 2025 New research shows that crops are far more vulnerable when too much rainfall originates from land rather than the ocean. Land-sourced moisture leads to weaker, less reliable rainfall, heightening drought risk. The U.S. Midwest and East Africa are ...
Dec. 12, 2025 A sudden, unexplained mass die-off is decimating sea urchins around the world, including catastrophic losses in the Canary Islands. Key reef-grazing species are reaching historic lows, and their ability to reproduce has nearly halted in some ...
Dec. 12, 2025 Fossils from Qatar have revealed a small, newly identified sea cow species that lived in the Arabian Gulf more than 20 million years ago. The site contains the densest known collection of fossil sea cow bones, showing that these animals once thrived ...
Dec. 11, 2025 Scientists tracking young Arizona Bald Eagles found that many migrate north during summer and fall, bucking the traditional southbound pattern of most birds. Their routes rely heavily on historic stopover lakes and rivers, and often extend deep into ...
Dec. 10, 2025 Researchers have uncovered surprising evidence that the deep ocean’s carbon-fixing engine works very differently than long assumed. While ammonia-oxidizing archaea were thought to dominate carbon fixation in the sunless depths, experiments show ...
Dec. 10, 2025 Researchers discovered that a long-misunderstood protein plays a key role in helping chromosomes latch onto the right “tracks” during cell division. Instead of acting like a motor, it works more like a stabilizer that sets everything up ...
Dec. 9, 2025 Microscopic fibers secretly shape how every organ in the body works, yet they’ve been notoriously hard to study—until now. A new imaging technique called ComSLI reveals hidden fiber orientations in stunning detail using only a rotating LED light ...
Dec. 9, 2025 Scientists discovered a small protein region that determines whether plants reject or welcome nitrogen-fixing bacteria. By tweaking only two amino acids, they converted a defensive receptor into one that supports symbiosis. Early success in barley ...
Dec. 8, 2025 Researchers revealed that the microbial metabolite TMA can directly block the immune protein IRAK4, reducing inflammation and improving insulin sensitivity. The molecule counteracts damage caused by high-fat diets and even protects mice from sepsis. ...
Dec. 8, 2025 Scientists found that kale’s prized nutrients are hard for the body to absorb unless they’re eaten with oil. Cooking doesn’t improve absorption, but adding oil-based dressings—or even more advanced nanoemulsion sauces—does. These ...
Dec. 7, 2025 Researchers successfully implanted a genetically modified pig liver into a human, proving that such an organ can function for an extended period. The graft supported essential liver processes before complications required its removal. Although the ...
Dec. 4, 2025 Scientists have captured a never-before-seen, high-resolution look at influenza’s stealthy invasion of human cells, revealing that the cells aren’t just helpless victims. Using a groundbreaking imaging technique, researchers discovered that our ...
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Dec. 11, 2025 A new economic modeling tool is helping Maine kelp farmers identify cost-saving strategies with remarkable precision. By analyzing farm design, weather, vessel types, and processing methods, it ...
Dec. 10, 2025 Humans don’t just recognize each other’s voices—our brains also light up for the calls of chimpanzees, hinting at ancient communication roots shared with our closest primate relatives. ...
Dec. 9, 2025 Ancient pterosaurs may have taken to the skies far earlier and more explosively than birds, evolving flight at their very origin despite having relatively small brains. Using advanced CT imaging, ...
Dec. 9, 2025 Scientists have confirmed that Nanotyrannus was a mature species, not a young T. rex. A microscopic look at its hyoid bone provided the key evidence, matching growth signals seen in known T. rex ...
Dec. 8, 2025 High-resolution imaging has revealed the internal layout of chromatin condensates, showing how DNA fibers fold and interact within these droplet-like structures. The findings connect molecular ...
Dec. 6, 2025 Scientists have discovered that complex life began evolving much earlier than traditional models suggested. Using an expanded molecular clock approach, the team showed that crucial cellular features ...
Dec. 5, 2025 Researchers have uncovered a new species of wolf snake on Great Nicobar Island and named it Lycodon irwini in tribute to Steve Irwin. The glossy black, non-venomous snake grows up to a meter and ...
Dec. 4, 2025 Experiments reveal that pond frogs can eat highly venomous hornets without suffering noticeable damage, even after repeated stings. Most frogs successfully consumed hornets, including the notorious ...
Dec. 4, 2025 Scientists have discovered a strange tubular structure inside Profftella, a symbiotic bacterium in the Asian citrus psyllid. These long, helical tubes, filled with ribosomes, show a complexity not ...
Dec. 3, 2025 Ancient anaconda fossils show that the snakes became giants soon after emerging in Miocene South America. Their size has stayed stable for over 12 million years, even though other huge reptiles went ...