The number of cells increases by mitosis, and as the embryo develops, the cells begin to differentiate or specialise. As half of the genetic make-up of the offspring is from one organism and half from another, it is genetically different from its parents. In other words, it shows variation. Reproduction and variation Asexual reproduction Only one parent is needed in asexual reproduction. Related questions How does asexual reproduction affect adaptability? How can asexual reproduction produce variation in a population?
How can asexual reproduction be an advantage to an organism? What are some examples of asexual reproduction? What does asexual reproduction of an organism normally result in? Spindle fibers cause the cell to elongate. In telophase a nuclear envelope forms around the chromosomes at each pole, and the tightly wound chromosomes start to unravel. The mitotic spindle starts to dissolve. Cytoplasm and organelles are divvied up and a cleavage furrow or cell plate in plants splits the two cells during cytokinesis.
Mitosis is a form of asexual reproduction in simple living organisms. The outcome of each cell cycle is two identical cells.
Mitotic checkpoints happen at certain stages of mitosis to ensure that each cell receives the same amount of DNA. Errors must be corrected or division halted because too many or too few chromosomes can harm the new cells.
Sexual reproduction happens through meiosis. In the first phase of meiosis, matching chromosomes pair up and swap gene snippets. That's why children with the same parents may or may not look alike. Errors in meiosis can result in chromosomal abnormalities and disease when gene functioning is impaired. Sexual reproduction is the production of offspring through the combination of sex cells or gametes. Meiosis is the process of producing gametes, each of which has half of the genetic material needed to create a new organism Fig.
In summary, mitosis produces two identical cells, each with the full amount of DNA. Meiosis produces four genetically unique cells, each with half the amount of DNA. See Table 2. Many species of algae have complex life histories and can reproduce through both sexual and asexual means. It is common for algae to have an alternation of generation, where one generation is made through mitotic cell division and the other is made from cells created through meiotic cell division.
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Growth, Development, and Reproduction. NGSS Performance Expectations: MS-LS Develop and use a model to describe why asexual reproduction results in offspring with identical genetic information and sexual reproduction results in offspring with genetic variation.
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