Every organism must reproduce create offspring in order to pass a part of themselves on into future generations. Depending on the organism, it can either reproduce using sexual or asexual reproduction, which both involve cell division.
The parental traits of sexually reproducing organisms will also mix to form a unique combination in the offspring, and an asexually reproduced organism will inherit all of its genetic material from the parents.
Reproduction is the process by which organisms create offspring and therefore replicate themselves in future generations. Unless spontaneous changes during reproduction, referred to as mutations, occur, the organism will receive all of its traits from its parents. Sexual reproduction involves intercourse, a process in which one organism usually a male inserts their own genetic material into another organism usually a female.
As this offspring grows, their development in the womb is referred to as pregnancy. When two organisms reproduce through sexual reproduction, the offspring display traits from both parents.
This is because of inheritance, or the passing on of traits, which was discovered by Gregor Mendel in the s. In fact, Mendel worked with pea plants to come up with his laws of inheritance.
Mendel chose plants with differences in a trait such as stem length, pea shape, or flower color. He noticed that if he mixed two plants with opposite traits, such as wrinkled and round pea shape, then all of their offspring would be round.
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There exists both a dominant, or trait that is expressed visible regardless of the other trait, and a recessive trait, which is hidden unless present in both sets of genes. These traits are expressed in combinations of either homozygous both dominant, heterozygous otheror homozygous recessive.
Homozygous means that the traits are either both of the dominant variety, or both of the recessive variety. In either combination, that trait will be fully expressed as both copies are the same.
These reproductive strategies are examples...
Heterozygous means that the traits are different—for example, one dominant and one recessive, in which case the dominant will be expressed in the organism. Generally, the dominant trait is expressed whenever it is present in an organism it will show up whether the organism is homozygous dominant or heterozygous and the recessive trait is only displayed when the organism is homozygous recessive.
How about mitosis? Explain. Meiosis...
DNA is a hereditary material, being passed down from previous generations, and therefore a child will receive pieces of it from both parents. The DNA is twisted into a shape called a double helix, which looks similar to a ladder. The chromosome itself consists of DNA coiled around proteins known as histones. However, chromosomes are usually extremely loosely coiled and therefore are almost impossible to see until they condense, or wrap tightly around the histones.
This condensation in shape occurs during cell replication.
These reproductive strategies are examples...
Organisms are made up of small units called cells, which are able to create copies of themselves to allow the organism to do things such as grow or repair itself. Reproduction of an organism occurs through a process of cell replication that is either called mitosis or meiosis. Meiosis occurs for the purpose of sexual reproduction which requires input from two individualsand creates cells called gametes the egg and the sperm.
The egg is the female reproductive cell, and it combines with the sperm male reproductive cell to form a combination of the parent cells that will later become an organism. Each of these daughter cells contains half the chromosomes of the original cell. There are 9 stages of meiosis, which occurs in two sets of cell division being denoted by either a I or a II. Humans usually have 46 chromosomes in each cell, so those created through meiosis are unique in that they only have half a set.
This is because when parents reproduce to create offspring, those offspring receive half a set from each parent which combine with the other. A cell with 23 chromosomes is called haploid, while one containing 46 is called diploid.
The process of dividing a cell into 4 haploid sex cells through meiosis is called gametogenesis. This is because the cells created through meiosis are called gametes. These are both referred to as gametes, or haploid sex cells.
This fusion of gamete cells is called a zygote. Asexual reproduction does not involve meiosis, instead, it involves mitosis, the type of cell division that all non-gamete body cells go through.
Mitosis involves only one set of cell division, and produces diploid cells identical to the parent cell. Additionally, because there is no new genetic material that appears in the offspring, asexual reproduction essentially produces clones of the parent. This type of reproduction commonly occurs in plants and invertebrates.
It can reproduce an entirely new, unique individual, or work to help an organism grow. This process allows the parent to reproduce many times with little effort and greater speed. Because these offspring are genetically identical, these populations may have greater susceptibility to disease.
Skip to main content. The Biology of Reproduction. What are Genes Made of? Meiosis I is the first set of cell division that happens during the creation of sex cells. Then they pair up and swap genes with the other through a process called recombination.
Then the covering around the chromosomes disappears, and they are freed into the body of the cell. Metaphase I The released chromosomes line up in the middle of the cell, and fibers attach to each of them. Anaphase I The pairs of individual Xs are pulled apart by these fibers, but the individual X-shaped chromosome stays intact unlike in the second set of meiosis.
Telophase I and Cytokinesis The chromosomes are pulled to opposite ends of the cell, with one of each chromosome ending up on each half of the cell. Then each full set of chromosomes is enclosed by the cell. The cell is then split into two pieces in a process called cytokinesis, with one set of 23 chromosomes within each new cell.
Meiosis II is the second set of cell division that occurs in the creation of sex cells. Prophase II Both new cells only have 23 chromosomes, which are released into the body of the new cell. Metaphase II In each cell, the chromosomes line up through the middle of the cell, and fibers attach to each half of the X-shaped chromosome.
Anaphase II Each half of the X is pulled to one end of the cell, turning them into individual chromosomes. Telophase II and Cytokinesis The chromosomes move to opposite ends of the cell, and each set of 23 is then packaged. The cell then undergoes cytokinesis again, resulting in four cells with 23 chromosomes each. University of California Museum of Paleontology. US National Library of Medicine. Last Updated 8 May Was this article helpful to you? For Educators fertilization haploid diploid cytokinesis sperm egg mitosis meiosis chromosome heterozygous homozygous dominant recessive mendel traits dna genes offspring organism Sex biology sexual asexual reproduction.
These reproductive strategies are examples of asexual reproduction, which look at different types of sexual life cycles used by different organisms, from humans to ferns to What happens between these two events, however, can differ a lot between In this
In what type of human cells does meiosis occur in asexual reproduction of life cycle, the single-celled zygote is the only diploid cell. In humans the male gamete is called sperm, and the female gamete is called an egg. When the gametes The egg contains a large food store to support the developing zygote until it can get food via the placenta.
Meiosis is the type of cell division used in sexual reproduction. It occurs only in the testes and ovaries. Meiosis is a special kind of cell division that occurs in germ cells. If humans reproduced asexually, you would have only one parent and you.
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