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Meiosis generates genetic variation in the diploid cell, in part by the exchange of genetic information between the pairs of chromosomes after they align (recombination). Thus, on this view, [28] an advantage of meiosis is that it facilitates the generation of genomic diversity among progeny, allowing adaptation to adverse changes in the ...
This is an accepted version of this page This is the latest accepted revision, reviewed on 16 February 2025. Cell division producing haploid gametes For the figure of speech, see Meiosis (figure of speech). For the process whereby cell nuclei divide to produce two copies of themselves, see Mitosis. For excessive constriction of the pupils, see Miosis. For the parasitic infestation, see Myiasis ...
The discovery of mitosis, meiosis and chromosomes is regarded as one of the 100 most important scientific discoveries of all times, [9] and one of the 10 most important discoveries in cell biology. [10] Meiosis was discovered and described for the first time in sea urchin eggs in 1876, by Oscar Hertwig.
Evolution is the change in the heritable characteristics of biological populations over successive generations. [1] [2] It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, resulting in certain characteristics becoming more or less common within a population over successive generations. [3]
In 1874, Eduard Strasburger discovered the alternation between diploid and haploid nuclear phases, [11] also called cytological alternation of nuclear phases. [15] Although most often coinciding, morphological alternation and nuclear phases alternation are sometimes independent of one another, e.g., in many red algae , the same nuclear phase ...
There are two popular and overlapping theories that explain the origins of crossing-over, coming from the different theories on the origin of meiosis.The first theory rests upon the idea that meiosis evolved as another method of DNA repair, and thus crossing-over is a novel way to replace possibly damaged sections of DNA. [9]
By studying sea urchins he proved that fertilization occurs due to the fusion of a sperm and egg cell. [ 2 ] [ 3 ] He recognized the role of the cell nucleus during inheritance and chromosome reduction during meiosis : in 1876, he published his findings that fertilization includes the penetration of a spermatozoon into an egg cell.
In biology, evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organization , from kingdoms to species , and individual organisms and molecules , such as DNA and proteins .