Sweet

Sweetness is one of the five basic tastes and is almost universally regarded as a pleasurable experience. Foods rich in simple carbohydrates such as sugar are those most commonly associated with sweetness, although there are other natural and artificial compounds that are sweet at much lower concentrations, allowing their use as non-caloric sugar substitutes.

Examples of foods that may be used as non-sugar sweet substitutes include saccharin, aspartame, xylitol and acesulfame K. Other compounds may alter perception of sweetness itself. The chemosensory basis for detecting sweetness, which varies among both individuals and species, has only been teased apart in recent years. A recent theoretical model of sweetness is the multipoint attachment theory, which involves multiple binding sites between a sweetness receptor and a sweet substance.

Yak

Taxonomy

Yaks belong to the genus Bos, and are therefore related to cattle (Bos primigenius taurus, Bos primigenius indicus). Mitochondrial DNA analyses to determine the evolutionary history of yaks have been somewhat ambiguous.

The yak may have diverged from cattle at any point between one and five million years ago, and there is some suggestion that it may be more closely related to bison than to the other members of its designated genus. Apparent close fossil relatives of the yak, such as Bos baikalensis, have been found in eastern Russia, suggesting a possible route by which yak-like ancestors of the modern American bison could have entered the Americas.

The species was originally designated as Bos grunniens ("grunting ox") by Linnaeus in 1766, but this name is now generally only considered to refer to the domesticated form of the animal, with Bos mutus ("mute ox") being the preferred name for the wild species. Although some authors still consider the wild yak to be a subspecies, Bos grunniens mutus, the ICZN made an official ruling in 2003 permitting the use of the name Bos mutus for wild yaks, and this is now the more common usage.

Except where the wild yak is considered as a subspecies of Bos grunniens, there are no recognised subspecies of yak.

Baird's Sparrow

These birds have a large bill, a large flat head, and a short forked tail. They have brown upper parts and white underparts, with streaking on the back, breast, and flanks. The face, nape, and crown stripe are yellowish.
Their breeding habitat is tall grass prairie regions in southern central Canada and the northern mid-western United States. The nest is an open cup in a well-hidden grassy location on the ground.
These birds migrate to the southwestern United States and northern Mexico.
They forage on the ground, mainly eating insects in summer and seeds in winter.
These birds usually nest in small loose colonies. Males sing from perches within their nesting territory. The song consists of a short series of high notes followed by a trill. This bird is more often seen than heard.
This bird's numbers have decreased with the loss of suitable habitat.
This bird was named after Spencer Fullerton Baird, an American naturalist.