evolution

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Related to Darwin's theory: Darwin's theory of evolution

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

(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.

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.

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 ?
"Darwin's theory challenged the notion of human exceptionalism," says Eugenie Scott, executive director of the National Center for Science Education, "and brought to light this idea that humans are a result of natural processes, meaning we were not as special as we once thought."
The first, The search for answers sets up the problem that Darwin's theory addressed.
are just two examples of religious voices who have no problem with Darwin's theory.
Gliboff, too, thinks that Haeckel took much of Darwin's theory on board, but he argues that Richards has consistently overestimated the German morphological tradition's commitment to the theory that both embryological development and evolution follow a step-by-step progressive sequence.
A CENTURY AND A HALF after the publication of Charles Darwin's On the Origin of Species, the Vatican has come out in support of Darwin's theory, long thought to be incompatible with Catholic teachings.
I AGREE with John Marchant (March, 6) that Darwin's theory is flawed and it's ironic that the general public are embracing the theory at a time when many scientists, especially microbiologists, are casting doubt on its validity.
"Religious teachings put pressure on Darwin's theory," she said, "saying Adam was created as the first human being and mankind originated from Adam.
There is a strong relationship between education and belief in Darwin's theory, as might be expected, ranging from 21% of those with high-school educations or less to 74% of those with postgraduate degrees.
One-off documentary, in which David Attenborough, left, shares his views on Darwin's theory and why he believes it is now more important than ever.
David Attenborough shares his views on Darwin's theory of evolution.
Darwin's Mistake postulates radical hypotheses--that Darwin's theory of evolution was ultimately false; dinosaurs and humans once co-existed; and the Earth's crust is relatively young.
"If a small church-based operation such as The Observer doesn't fear a backlash from those who oppose Darwin's theory of evolution, then secular corporate entities with much greater resources shouldn't fear it either."