Jump to content

Portal:Biology

From Wikipedia, the free encyclopedia
  • Darlingtonia californica — California pitcher plant This patch of Darligtonias is the northernmost natural patch.
    Darlingtonia californica — California pitcher plant This patch of Darligtonias is the northernmost natural patch.
  • Harvestman (Opilio canestrinii), male, on a geranium flower. He is cleaning his leg by drawing it through his jaws.
    Harvestman (Opilio canestrinii), male, on a geranium flower. He is cleaning his leg by drawing it through his jaws.

Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are composed of at least one cell that processes hereditary information encoded in genes, which can be transmitted to future generations. Another major theme is evolution, which explains the unity and diversity of life. Energy processing is also important to life as it allows organisms to move, grow, and reproduce. Finally, all organisms can regulate their own internal environments. (Full article...)

Featured article

The Cretaceous–Paleogene (K–Pg) extinction event, also known as the K–T extinction, was the mass extinction of three-quarters of the plant and animal species on Earth approximately 66 million years ago. The event caused the extinction of all non-avian dinosaurs. Most other tetrapods weighing more than 25 kg (55 lb) also became extinct, with the exception of some ectothermic species such as sea turtles and crocodilians. It marked the end of the Cretaceous period, and with it the Mesozoic era, while heralding the beginning of the current era, the Cenozoic. In the geologic record, the K–Pg event is marked by a thin layer of sediment called the K–Pg boundary, Fatkito boundary or K–T boundary, which can be found throughout the world in marine and terrestrial rocks. The boundary clay shows unusually high levels of the metal iridium, which is more common in asteroids than in the Earth's crust.

As originally proposed in 1980 by a team of scientists led by Luis Alvarez and his son Walter, it is now generally thought that the K–Pg extinction was caused by the impact of a massive asteroid 10 to 15 km (6 to 9 mi) wide, 66 million years ago causing the Chicxulub crater, which devastated the global environment, mainly through a lingering impact winter which halted photosynthesis in plants and plankton. The impact hypothesis, also known as the Alvarez hypothesis, was bolstered by the discovery of the 180 km (112 mi) Chicxulub crater in the Gulf of Mexico's Yucatán Peninsula in the early 1990s, which provided conclusive evidence that the K–Pg boundary clay represented debris from an asteroid impact. The fact that the extinctions occurred simultaneously provides strong evidence that they were caused by the asteroid. A 2016 drilling project into the Chicxulub peak ring confirmed that the peak ring comprised granite ejected within minutes from deep in the earth, but contained hardly any gypsum, the usual sulfate-containing sea floor rock in the region: the gypsum would have vaporized and dispersed as an aerosol into the atmosphere, causing longer-term effects on the climate and food chain. In October 2019, researchers asserted that the event rapidly acidified the oceans and produced long-lasting effects on the climate, detailing the mechanisms of the mass extinction. (Full article...)

Featured pictures

Get involved

For editor resources and to collaborate with other editors on improving Wikipedia's Biology-related articles, see WikiProject Biology.


Categories

» Categories: Category:Biology, Category:Biology books

Topics

» Outline of biology, History of biology, Timeline of biology and organic chemistry, Index of biology articles

Vital articles

» subpages:Biological and health sciences, Biology, biochemistry, anatomy, and physiology, Animals, Plants, fungi, and other organisms, Health, medicine, and disease


Discover Wikipedia using portals
Retrieved from "https://en.wikipedia.org/w/index.php?title=Portal:Biology&oldid=1269911304"