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[2] 1,2-dipolar compounds, such as ylides, are sometimes excluded from the definition. [3] Some zwitterions, such as amino acid zwitterions, are in chemical equilibrium with an uncharged "parent" molecule. Betaines are zwitterions that cannot isomerize to an all-neutral form, such as when the positive charge is located on a quaternary ammonium ...
A gastrolith, also called a stomach stone or gizzard stone, is a rock held inside a gastrointestinal tract. Gastroliths in some species are retained in the muscular gizzard and used to grind food in animals lacking suitable grinding teeth. In other species the rocks are ingested and pass through the digestive system and are frequently replaced.
Food chain in a Swedish lake. Osprey feed on northern pike, which in turn feed on perch which eat bleak which eat crustaceans.. A food chain is a linear network of links in a food web, often starting with an autotroph (such as grass or algae), also called a producer, and typically ending at an apex predator (such as grizzly bears or killer whales), detritivore (such as earthworms and woodlice ...
Also acid ionization constant or acidity constant. A quantitative measure of the strength of an acid in solution expressed as an equilibrium constant for a chemical dissociation reaction in the context of acid-base reactions. It is often given as its base-10 cologarithm, p K a. acid–base extraction A chemical reaction in which chemical species are separated from other acids and bases. acid ...
Zwitterions can be seen as dipolar compounds, unless dipolar not only means "with positive and negative charge", but also that the compound has only two charged centers (don't know if all dipolar compounds have only two charged centers). There are zwitterions with more than two; e.g. we have amino acids with multiple amino's.
The term "lithotroph" was created from the Greek terms 'lithos' (rock) and 'troph' (consumer), meaning "eaters of rock". Many but not all lithoautotrophs are extremophiles . The last universal common ancestor of life is thought to be a chemolithotroph (due to its presence in the prokaryotes). [ 2 ]
Mammals like Andrewsarchus were at the top of the food-chain. The Late Eocene saw the rebirth of seasons, which caused the expansion of savanna-like areas, along with the evolution of grasses. [15] [16] The end of the Eocene was marked by the Eocene–Oligocene extinction event, [17] [18] [19] the European face of which is known as the Grande ...
Definition (marine biology), context, extra terminology [ edit ] In marine biology , the neritic zone , also called coastal waters , the coastal ocean or the sublittoral zone , [ 3 ] refers to that zone of the ocean where sunlight reaches the ocean floor , that is, where the water is never so deep as to take it out of the photic zone .