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
September 9, 2026
Sep. 9, 2026 Insects quietly hold much of the natural world together, yet conservation efforts are overlooking the tropical regions where more than 80 percent of insect species live. Monash University researchers ...
Sep. 7, 2026 Scientists have found evidence that some gut bacterial populations can spread rapidly between people and across continents, suggesting the microbiome may be more transmissible than previously thought. The research also revealed hidden bacterial ...
Sep. 5, 2026 Researchers at UC San Diego have demonstrated that a key cellular enzyme can accurately read an eight-letter genetic alphabet, doubling the four letters used by all known life on Earth. Detailed imaging revealed that RNA polymerase handles synthetic ...
Sep. 4, 2026 A substance found in edible sea squirts appeared to reverse several signs of aging in older mice. Plasmalogen supplements improved memory and learning, strengthened connections between brain cells, reduced inflammation, and even helped the mice grow ...
Sep. 4, 2026 Puerto Rico’s normally rainy season has instead brought a severe and fast-growing drought. By August 25, three-quarters of the territory was in at least moderate drought, with extreme drought covering 44 percent and some areas receiving less than ...
Sep. 4, 2026 MIT researchers have created bacterial “transistors” that can be wired together into living circuits capable of performing calculations and directing chemical signals. One day, these biological computers could coat plant roots or leaves, ...
Sep. 3, 2026 Morning glories may be getting caught in an evolutionary tug-of-war between surviving climate change and attracting increasingly scarce pollinators. Over just nine years, researchers found that the plants’ rate of adaptation plunged by 96%, even ...
Sep. 3, 2026 Scientists discovered that more than 500 species of vesper bats possess two separate sets of antibody genes, an immune arrangement never before found in mammals. The surprising system could help explain how bats tolerate so many viruses without ...
Aug. 30, 2026 Researchers have produced a form of Spirulina containing biologically active vitamin B12 at levels comparable to beef. By carefully controlling the light used to grow the algae, they overcame a major problem with conventional Spirulina, which mainly ...
Aug. 29, 2026 Dogs and humans may have more in common when it comes to aging than scientists realized. Researchers with the Dog Aging Project found that patterns of small molecules in dogs’ blood were linked to longer or shorter lifespans in remarkably similar ...
Aug. 28, 2026 Every one of 212 plant-based meat alternatives and drinks tested in the UK contained at least one naturally occurring fungal toxin, though concentrations remained below recommended EU guideline ...
Aug. 26, 2026 DNA from a nearly 190-year-old museum specimen has helped scientists confirm a distinct Himalayan pangolin species hiding in plain sight in Nepal and northern India. The discovery could give conservationists a powerful new way to trace illegally ...
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Sep. 9, 2026 Two major alien-life announcements in 2025 generated enormous excitement, but most astrobiologists remained unconvinced. Only 6.6% of surveyed experts thought possible biological molecules on K2-18b ...
Sep. 8, 2026 Researchers discovered that combinations of toxin-blocking proteins naturally found in rattlesnake blood can powerfully neutralize venom from several dangerous snake species. In lab tests, the ...
Sep. 8, 2026 Scientists have identified a giant new dinosaur from Brazil that reached about 20 meters long and lived 120 million years ago. Its surprising evolutionary ties to a Spanish dinosaur suggest its ...
Sep. 8, 2026 The extinct “American cheetah” was not really a cheetah at all, but a puma relative with an unexpectedly flexible lifestyle. Fossils from the Yukon suggest northern populations survived partly by ...
Sep. 7, 2026 A critically endangered roloway monkey has given birth just months after surgeons performed an unusual operation that saved her foot from amputation. ...
Sep. 5, 2026 A common frog found across Ecuador and Colombia has finally been recognized as its own species after more than a century of mistaken identity. Museum specimens from the 1800s helped scientists reveal ...
Sep. 4, 2026 Scientists have overturned a leading explanation for why male and female bonnethead sharks have differently shaped heads. Instead of males developing a pointed snout at maturity, both sexes actually ...
Sep. 3, 2026 Scientists have discovered a strange black “devil flower” in Thailand that lives mostly underground, steals nutrients from fungi, and looks strikingly unlike a typical plant. The newly named ...
Sep. 3, 2026 A newly discovered microbe living inside ancient stromatolite communities may offer a rare look at how complex life first emerged. Researchers captured the first direct images of an Asgard archaeon ...
Sep. 2, 2026 A meter-long scorpion with massive pincers stalked ancient Britain 415 million years ago, long before forests and the better-known age of giant insects. Its surprising size and possible semi-aquatic ...