Portal:Evolutionary biology

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https://en.wikipedia.org/wiki/Portal:Evolutionary_biology
The Evolutionary Biology Portal

Introduction

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Evolutionary biology is the subfield of biology that studies the evolutionary processes ( natural selection, common descent, speciation) that produced the diversity of life on Earth. In the 1930s, the discipline of evolutionary biology emerged through what Julian Huxley called the modern synthesis of understanding, from previously unrelated fields of biological research, such as genetics and ecology, systematics and paleontology.

The investigational range of current research widened to encompass the genetic architecture of adaptation, molecular evolution, and the different forces that contribute to evolution, such as sexual selection, genetic drift, and biogeography. Moreover, the newer field of evolutionary developmental biology ("evo-devo") investigates how embryogenesis, the development of the embryo, is controlled, thus yielding a wider synthesis that integrates developmental biology with the fields of study covered by the earlier evolutionary synthesis. ( Full article...)

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Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes that are passed on from parent to offspring during reproduction. Different characteristics tend to exist within any given population as a result of mutation, genetic recombination and other sources of genetic variation. Evolution occurs when evolutionary processes such as natural selection (including sexual selection) and genetic drift act on this variation, resulting in certain characteristics becoming more common or rare within a population. It is this process of evolution that has given rise to biodiversity at every level of biological organisation, including the levels of species, individual organisms and molecules.

The scientific theory of evolution by natural selection was conceived independently by Charles Darwin and Alfred Russel Wallace in the mid-19th century and was set out in detail in Darwin's book On the Origin of Species. Evolution by natural selection was first demonstrated by the observation that more offspring are often produced than can possibly survive. This is followed by three observable facts about living organisms: (1) traits vary among individuals with respect to their morphology, physiology and behaviour ( phenotypic variation), (2) different traits confer different rates of survival and reproduction (differential fitness) and (3) traits can be passed from generation to generation ( heritability of fitness). Thus, in successive generations members of a population are more likely to be replaced by the progenies of parents with favourable characteristics that have enabled them to survive and reproduce in their respective environments. In the early 20th century, other competing ideas of evolution such as mutationism and orthogenesis were refuted as the modern synthesis reconciled Darwinian evolution with classical genetics, which established adaptive evolution as being caused by natural selection acting on Mendelian genetic variation. ( Full article...)

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Gene-duplication
Credit: User:TimVickers

The image depicts the duplication of part of a chromosome.

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  • ...that adaptations enable living organisms to cope with environmental stresses and pressures?
  • ...that maintained gene flow between two populations can also lead to a combination of the two gene pools, reducing the genetic variation between the two groups?
  • ...that all forms of natural speciation have taken place over the course of evolution, though it still remains a subject of debate as to the relative importance of each mechanism in driving biodiversity?
  • ...that despite the relative rarity of suitable conditions for fossilization, approximately 250,000 fossil species are known?
  • ...that genetic sequence evidence thus allows inference and quantification of genetic relatedness between humans and other apes?

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