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evolution

 [ev″o-lu´shun]
the process of development in which an organ or organism becomes more and more complex by the differentiation of its parts; a continuous and progressive change according to certain laws and by means of resident forces.
convergent evolution the development, in animals that are only distantly related, of similar structures or functions in adaptation to similar environments.

ev·o·lu·tion

(ev'ō-lū'shŭn),
1. A continuing process of change from one state, condition, or form to another.
2. A progressive distancing between the genotype and the phenotype in a line of descent.
3. The liberation of a gas or heat in the course of a chemical or enzymatic reaction.
[L. e-volvo, pp. -volutus, to roll out]

evolution

/evo·lu·tion/ (ev″ah-loo´shun) a developmental process in which an organ or organism becomes more and more complex by differentiation of its parts; a continuous and progressive change according to certain laws and by means of resident forces.
convergent evolution  the appearance of similar forms and/or functions in two or more lines not sufficiently related phylogenetically to account for the similarity.
organic evolution  the origin and development of species; the theory that existing organisms are the result of descent with modification from those of past times.

evolution

(ĕv′ə-lo͞o′shən, ē′və-)
n.
1. A continuing process of change from one state, condition, or form to another.
2. Change in the genetic composition of a population during successive generations, often resulting in the development of new species. The mechanisms of evolution include natural selection acting on the genetic variation among individuals, mutation, migration, and genetic drift.

evolution

[ev′əlo̅o̅′shən]
Etymology: L, evolvere, to roll forth
1 a gradual, orderly, and continuous process of change and development from one condition or state to another. It encompasses all aspects of life, including physical, psychological, sociological, cultural, and intellectual development, and involves a progressive advancement from a simple to a more complex form or state through the processes of modification, differentiation, and growth.
2 a change in the genetic composition of a population of organisms over time.
3 the appearance over long periods of time of new taxonomic groups of organisms from preexisting groups. Kinds of evolution are convergent evolution, determinant evolution, emergent evolution, organic evolution, orthogenic evolution, and saltatory evolution. evolutionist, n.

ev·o·lu·tion

(ev'ŏ-lū'shŭn)
1. A continuing process of change from one state, condition, or form to another.
2. A progressive distancing between the genotype and the phenotype in a line of descent.
[L. e-volvo, pp. -volutus, to roll out]

evolution

The theory that all living organisms have developed in complexity, from a simple life form. Evolution occurs by the natural selection of those who, by the fortune of spontaneous random changes (mutations), happen to be best suited to their contemporary environment, to survive and reproduce. It does not occur by the passing on to offspring of characteristics acquired during the lifetime of an individual. Characteristics are passed on by the transmission of DNA from parents to offspring and, unless mutation has occurred, this DNA is an identical copy of the DNA of preceding generations.

evolution

an explanation of the way in which present-day organisms have been produced, involving changes taking place in the genetic make-up of populations that have been passed on to successive generations. According to DARWINISM, evolutionary MUTATIONS have given rise to changes that have, through NATURAL SELECTION, either survived in better adapted organisms (see ADAPTATION, GENETIC), or died out. Evolution is now generally accepted as the means which gives rise to new species (as opposed to SPECIAL CREATION) but there is still debate about exactly how it has taken place and how rapidly changes can take place. See LAMARCKISM.

evolution

the process of development in which an organ or organism becomes more and more complex by the differentiation of its parts; a continuous and progressive change according to certain laws and by means of resident forces.

convergent evolution
the development, in animals that are only distantly related, of similar structures or functions in adaptation to similar environment.
divergent evolution
the development of different characteristics in animals that were closely related in response to being placed in different environments.

Patient discussion about evolution

Q. How the bacterias are produced?

A. The Bacteria are a large group of unicellular microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals. (The name comes from the Greek bakterion, meaning small staff.) Bacteria are ubiquitous in every habitat on Earth, growing in soil, acidic hot springs, radioactive waste,[2] water, and deep in the Earth's crust, as well as in organic matter and the live bodies of plants and animals. There are typically 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water; in all, there are approximately five nonillion (5×1030) bacteria on Earth,[3] forming much of the world's biomass.[4] Bacteria are vital in recycling nutrients, with many important steps in nutrient cycles depending on these organisms, such as the fixation of nitrogen from the atmosphere and putrefaction. http://en.wikipedia.org/wiki/Bacteria Hope this helps.

More discussions about evolution
References in periodicals archive ?
In the third section, the 4 chapters extensively discuss the evolution of selected groups of microbial pathogens: group A Streptococcus and Staphylococcus aureus; enteric pathogens such as Escherichia coli, Salmonella enterica, and Yersinia spp.
Second, although base substitutions, insertions and deletions, homologous recombination, and lateral gene transfer are discussed throughout the book, a generalized quantitative review of the relative contributions of these processes during the evolution of certain groups of microbial pathogens (e.
Of special note are 2 chapters that are often missing in traditional medical microbiology books: 1 describes how long-term experimental evolutionary studies in the laboratory can contribute to our understanding of microbial pathogen evolution in the environment and clinics, and the other describes how gene inactivation and gene loss can be creative forces during the evolution of many microorganisms, especially obligate intracellular pathogens.
Wireless Evolutions installed a variety of BelAir Networks wireless mesh nodes in the two residential complexes to create the powerful network.
I am very pleased with the wireless Internet that was installed by Wireless Evolutions," stated James Wheeler, NTC Property resident.
Wireless Solutions Sweden AB (WSS), part of the Allgon group, has signed a joint agreement with Link Evolution Corp of Japan.
Link Evolution delivers wireless communications solutions to Matsushita, Ricoh, Sony and other Japanese electronic hardware manufacturers.
In conjunction with this acquisition, Evolutions has also acquired a license from H.
Michael Nafash, president and chief executive officer of Evolutions said,"This acquisition substantially increases revenues to be derived from the apparel division of our company.
Michael Nafash, president and chief executive officer of Evolutions said, "The shareholder approval of the merger and reverse stock split places the Company in a position where it can embark on a course of long-term growth through acquisitions and internal expansion.
Changes in gene frequency brought about by random genetic drift, gene flow, and natural selection lead to the evolution of populations.
His neutral theory of molecular evolution accepts that, for any gene, a large proportion of all possible mutants are harmful to their carriers; these mutants are eliminated or kept at very low frequency by natural selection.