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The Differences Between Asexual and Sexual Reproduction As you read over the material, use the provided words and phrases to compare and contrast asexual and sexual reproduction. Organisms need to make more organisms like themselves through reproduction. Reproduction is the production of offspring or new individuals through a sexual or asexual process. In a nutshell, reproduction is the creation of new individuals from previously existing organisms. Most organisms reproduce sexually which includes fertilization of an egg and sperm, but a few do reproduce asexually without fertilization of an egg and sperm. Asexual reproduction is the simplest form of reproduction, occurring in many simple plants, animals, bacteria, protest, fungi, and micro-organism. In asexual reproduction there is only one parent. The result of asexual reproduction is an offspring that is identical to the parent. It can be considered a clone of the parent because it has the exact same genetic information as the single parent. Example of asexual reproduction is binary fission in bacteria as seen to the right. In binary fission one cell divides to form two identical cells. A cell first duplicates its genetic material and then divides into two separate cells. Each new cell has its own complete copy of the parent’s genetic information. An advantage of asexual reproduction is that an organism can reproduce by itself and it can occur rapidly. Asexual reproduction can lead to rapid population growth of a species. Another example of an organism that reproduces asexually is the hydra as seen to the left. The hydra uses a form of asexual reproduction called budding. In budding part of the parent develops into a new organism. The new organism then pinches off from the parent and lives independently. The new organism is genetically identical to its parent. A disadvantage to asexual reproduction is that only clones are reproduced – there is no genetic variation. An organism would not be able to adapt and evolve to a changing environment. The flatworm Planaria can also reproduce asexually by fragmentation. In this form the body of the parent breaks into two distinct pieces, each which can produce and offspring. Majority of animals such as humans reproduce by sexual reproduction. In sexual reproduction, two parents combine their genetic material to produce offspring that are genetically different from both parents. Genetic material from the parents is transferred in a special cell called a sperm for the male and an egg for the female. When the egg and the sperm join together it is called fertilization. During fertilization, the egg and sperm combine their single sets of chromosomes to form a zygote containing two sets, or the diploid number, of chromosomes for a species (half from each parent). With sexual reproduction the offspring receives half of its genetic material from its father and half of its genetic material from its mother. However, the mitochondrion DNA is received solely from the mother. An advantage of sexual reproduction is genetic variation. With genetic variation an organism has a higher chance of adapting and evolving with a changing environment. A disadvantage of sexual reproduction is that two organisms are involved.
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