Search results
Results from the WOW.Com Content Network
Homochirality is an obvious characteristic of life on Earth, yet extraterrestrial samples contain largely racemic compounds. [7] It is not known whether homochirality existed before life, whether the building blocks of life must have this particular chirality, or whether life must be homochiral at all.
Thomas began writing a monthly essay “Notes of a Biology Watcher” in the New England Journal of Medicine in 1971 while he was at Yale. In 1973 he became the president of the Sloan-Kettering Institute in New York. Lewis Thomas published multiple books throughout his career, the first being The Lives of a Cell: Notes of a Biology Watcher.
Direct reciprocity was proposed by Robert Trivers as a mechanism for the evolution of cooperation. [1] If there are repeated encounters between the same two players in an evolutionary game in which each of them can choose either to "cooperate" or "defect", then a strategy of mutual cooperation may be favoured even if it pays each player, in the short term, to defect when the other cooperates.
Parasitism is a relationship between species, where one organism, the parasite, lives on or in another organism, the host, causing it some harm, and is adapted structurally to this way of life. [20] The parasite either feeds on the host, or, in the case of intestinal parasites, consumes some of its food.
The evolution of biological complexity is one important outcome of the process of evolution. [1] Evolution has produced some remarkably complex organisms – although the actual level of complexity is very hard to define or measure accurately in biology, with properties such as gene content, the number of cell types or morphology all proposed as possible metrics.
A mathematical example of "survival of the fittest" is given by Haldane in his paper "The Cost of Natural Selection". [62] Haldane called this process "substitution" or more commonly in biology, this is called "fixation". This is correctly described by the differential survival and reproduction of individuals due to differences in phenotype.
Another example are the most well-characterised endocannabinoids like anandamide (N-arachidonoylethanolamide; AEA) and 2-arachidonoylglycerol (2-AG), whose synthesis occurs through the action of a series of intracellular enzymes activated in response to a rise in intracellular calcium levels to introduce homeostasis and prevention of tumor ...
Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. [1] [2] All living organisms are made of cells. A cell is the basic unit of life that is responsible for the living and functioning of organisms. [3] Cell biology is the study of the structural and functional ...