Search results
Results from the WOW.Com Content Network
The Purple Earth Hypothesis (PEH) is an astrobiological hypothesis, first proposed by molecular biologist Shiladitya DasSarma in 2007, [1] that the earliest photosynthetic life forms of Early Earth were based on the simpler molecule retinal rather than the more complex porphyrin -based chlorophyll, making the surface biosphere appear purplish ...
Earth forms 3.4 billion years ago First photosynthetic bacteria appear 2.7 billion years ago Cyanobacteria become the first oxygen producers 2.4 – 2.3 billion years ago Earliest evidence (from rocks) that oxygen was in the atmosphere 1.2 billion years ago Red and brown algae become structurally more complex than bacteria 0.75 billion years ago
Photosynthesis (/ ˌfoʊtəˈsɪnθəsɪs / FOH-tə-SINTH-ə-sis) [ 1 ] is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabolism.
The Australasian shoveler (Spatula rhynchotis) is a species of dabbling duck in the family Anatidae. It is native to southwestern and southeastern Australia, including Tasmania, and New Zealand. It ranges in length from 46 to 53 centimetres (18 to 21 inches) and lives in heavily vegetated swamps. This male Australasian shoveler was photographed ...
In the 18th century, purple was a color worn by royalty, aristocrats and other wealthy people. Good-quality purple fabric was too expensive for ordinary people. The first cobalt violet, the intensely red-violet cobalt arsenate, was highly toxic. Although it persisted in some paint lines into the 20th century, it was displaced by less toxic ...
Lithotroph. Lithotrophs are a diverse group of organisms using an inorganic substrate (usually of mineral origin) to obtain reducing equivalents for use in biosynthesis (e.g., carbon dioxide fixation) or energy conservation (i.e., ATP production) via aerobic or anaerobic respiration. [1] While lithotrophs in the broader sense include ...
Purple has long been associated with royalty, originally because Tyrian purple dye—made from the secretions of sea snails—was extremely expensive in antiquity. [1] Purple was the color worn by Roman magistrates; it became the imperial color worn by the rulers of the Byzantine Empire and the Holy Roman Empire, and later by Roman Catholic ...
Water covers about 71% of Earth's surface. [1] The origin of water on Earth is the subject of a body of research in the fields of planetary science, astronomy, and astrobiology. Earth is unique among the rocky planets in the Solar System in having oceans of liquid water on its surface. [2] Liquid water, which is necessary for all known forms of ...