Entry Category: Science and Technology - Starting with G

Gars are a primitive group of euryhaline fishes dating back to the late Jurassic to early Cretaceous Period, about 150 million years ago. Gars are one of the most recognizable fishes because of their slender torpedo-shaped bodies, ganoid scales, and long snouts with numerous teeth. Dorsal and anal fins are set far back on the body, and the caudal fin is rounded, with a condition known as abbreviate-heterocercal. Gars are unusual among fishes in that their vascularized swim bladders can function as lungs; they must surface periodically to take a gulp of air. Arkansas hosts four gar species: the alligator gar (Atractosteus spatula), spotted gar (Lepisosteus oculatus), longnose gar (L. osseus), and shortnose gar (L. platostomous). Fossilized gar specimens have …

Neal Bryant Garver arrived in Little Rock (Pulaski County) in 1918 to help provide engineering services for the construction of a munitions plant during World War I. As the Arkansas State Highway Department’s first bridge engineer, Garver also led the design of more than 2,000 bridges from 1921 to 1950, helping to modernize the state’s roadways by adding river crossings. In 1919, Garver started what became the state’s largest engineering firm, which began by providing structural engineering services for Little Rock High School (later called Little Rock Central High), North Little Rock High School, the Pulaski County Jail, and many other structures. Neal Garver was born on February 17, 1877, in Lee County, Iowa, near the Mississippi River, to the …

The Phylum Gastrotricha (commonly called “hairybacks”) comprises about 800 species of marine, brackish, and freshwater microscopic invertebrates. Twelve genera and fewer than 100 species of freshwater gastrotrichs are known from North America. However, in North America, perhaps 75 to 90 percent of the probable diversity of freshwater gastrotrichs species are undescribed. Gastrotrichs are widely distributed cosmopolitan organisms that are divided into two orders: the Macrodasyida (with nine families), which, except for two freshwater species (Marinellina flagellata and Redudasys fornerise), are marine, and the Chaetonotida (seven families), some of which are marine, estuarine, and semi-terrestrial forms, while others are primarily found in freshwater. The Chaetonotida can be further broken down into two suborders: the Multitubulatina (Nesodasys) and the Paucitublatina (Chaetonotus, Dasydytes, …

Geckos are lizards that belong to the Class Reptilia, Order Squamata, Suborder Sauria (Lacertilia), and Infraorder Gekkota within seven families, including Carphodactylidae (seven genera, thirty species), Diplodactylidae (twenty-five genera, 137 species), Eublepharidae (six genera, thirty species), Gekkonidae (fifty-four genera, 1,264 species), Pygopodidae (eight genera, thirty-five species), Phyllodactylidae (nine genera, 100 species), and Sphaerodactylidae (twelve genera, 200 species). By far, the true geckos (Gekkonidae) are the largest family of lizards. Many common geckos are members of this family, including dtellas (Gehyra), house geckos (Hemidactylus), true geckos (Gekko), and day geckos (Phelsuma). Geckos are cosmopolitan in distribution and are particularly species-rich in the tropics. At least one type of gecko is found in Arkansas. Geckos probably evolved in the Lower Cretaceous, and …

William Lee Gerig was a civil engineer working on railroads and dams in both the United States and abroad, including his service as chief engineer for the construction of the Panama Canal. By the end of his career, he had consulted on every dam built in the United States from 1923 to 1938. William Gerig was born on March 25, 1866, in Boone County, Missouri, the son of Swiss immigrants Francis Joseph and Carolyn Degan Gerig. William Gerig’s grandfather Degen came to America in the early eighteenth century to practice civil engineering. His father, Francis Joseph, assisted in the construction of the Suez Canal before settling in Missouri. As a young boy, the instruments that surveyors used fascinated Gerig, and …

North American freshwater fishes of the family Hiodontidae (order Hiodontiformes or Osteoglossiformes) include the goldeye (Hiodon alosoides) and mooneye (H. tergisus). The goldeye ranges from James Bay (bordering the provinces of Ontario and Quebec) in Canada and the Mississippi River basins from the Northwest Territory to western Pennsylvania and Ohio south to Louisiana. In Arkansas, H. alosoides is found sporadically in lakes and the larger turbid rivers of the state, including the Arkansas and Mississippi, and the smaller Black River. The mooneye (also called the “freshwater tarpon”) ranges from the St. Lawrence–Great Lakes, Mississippi River, and Hudson Bay basins from Quebec and Alberta, Canada, east to western North Carolina and south to Louisiana. In Arkansas, H. tergisus occurs in large …

Mary Lowe Good was a renowned chemist, industrial innovator, professor, and government leader. Good was the first woman in Arkansas to earn a PhD in the so-called hard sciences such as chemistry or physics (fellow Arkansan Margaret Pittman was awarded a PhD in bacteriology in 1929). Good was the first woman elected to the board of the American Chemical Society, and she held important U.S. government positions under the administrations of four presidents. Mary Lowe was born in Grapevine, Texas, on June 20, 1931. Her parents were Winnie Lowe, who was a teacher and librarian, and John Lowe, a school principal; she had three siblings, including Betty Ann Lowe, who became a renowned hospital administrator. In 1942, the family moved …

Greers Ferry Dam on the Little Red River, approximately three miles north of Heber Springs (Cleburne County), is a concrete dam built between 1959 and 1962. The dam’s primary function is flood control, but it also serves as a hydroelectric power plant. Greers Ferry Lake, created as a result of the dam, is a popular recreational destination. The flow of the Little Red River was uncontrolled during the first half of the twentieth century, resulting in almost yearly flooding downstream; high water levels in the Little Red River could compound flooding problems further downstream along the White River. In 1938, Congress passed the Flood Control Act, which authorized the U.S. Army Corps of Engineers to build dams on most of …

The grotto salamander (Eurycea spelaea) is a species of lungless salamander in the Phylum Chordata, Subphylum Vertebrata, Class Amphibia, Order Caudata, and Family Plethodontidae. It was originally described as Typhlotriton spelaeus but is now considered a member of the genus Eurycea. It is endemic to wet caves, sinkholes, and karst regions beneath the Springfield and Salem Plateaus of the Ozark Mountains of 120 individual sites in northern Arkansas, 124 sites in southwestern Missouri, forty-three sites in northeastern Oklahoma, and one county (Cherokee) in extreme southeastern Kansas. Its natural habitats are freshwater springs, inland karsts, and caves. It is not listed by the federal government as endangered or threatened, but it is vulnerable to changes in groundwater quality and a reduction …