Reproductive Success
Asexual vs. Sexual Reproduction
The major difference between sexual reproduction and asexual reproduction is that sexual reproduction requires two parents while asexual reproduction only requires one parent. During sexual reproduction, one cell from each of the parents come together and form the first cell of the new organism that are genetically variable (look different than the parents). During asexual reproduction, one parent produces offspring that looks the same as the parent (is a clone).
There are multiple different forms of asexual reproduction. One of them is binary fission that occurs mostly in bacteria. During binary fission, the parent doubles its DNA and splits in two, resulting in an identical new organism. Another form of asexual reproduction is budding where the offspring branches off from the parent and grows. Fragmentation is another one that occurs in sponges and starfish arms during which a piece of the organism grows a new organism. The last form of asexual reproduction is vegetative propagation where a plant grows from a plant.
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Mitosis is the process by which a cell splits into two identical daughter cells that each have a full set of chromosomes (diploid cells). It has 5 different steps. The first step is interphase which is the non-dividing phase. The second phase is prophase during which the nucleus disappears, the chromosomes appear, and the spindle fibers form. Next comes metaphase where the chromosomes line up in the center of the cell. The fourth step is anaphase where the sister chromatids are pulled apart. The final step is telophase where two cells are formed.
During meiosis, instead of making two cells, four genetically variable sex cells (gametes) are made. They have a half set of chromosomes (haploid cells). Unlike mitosis, it isn't reproduction because the gametes produced need to be fertilized in order to make an offspring. The steps of meiosis are very similar to those of mitosis. However, it doesn't stop after two cells are formed and it repeats until four cells are formed. It happens in men in the testes during puberty and in women in the ovaries. In women, half of the gametes are produced before birth and the other half are produced each month. |
Scorpion Reproduction
Scorpions reproduce sexually. The males and females find and identify each other through vibrations and pheromone (a hormone excreted by the scorpions). After the two scorpions decide that they want to mate, they start to perform a dance. The male grabs ahold of the female's pedipalps and leads her around trying to find a spot to secrete his spermatophore. In addition to holding pedipalps, sometimes the scorpions "kiss" by grasping each other's chelicerae. Sometimes, the male even injects the female with a small amount of venom to make her calmer. Once he has found a place he is satisfied with, which may take between 1 to 25 hours, he secretes the spermatophore and shows the female where it is so that she can bring it into her body through her genital opercula. The sperm is then released once it enters the female and she is fertilized. Once they have finished mating, the male leaves very quickly because if he doesn't, the female may try to eat him.
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