Importance of Reproduction
Reproduction is important because the survival of a species depends on its reproductive success. In order for reproduction to be successful, a group of organisms that interbreed must produce a fertile offspring. If it is sterile, the organism cannot reproduce, which doesn't allow genes to get passed on.
Asexual Vs. Sexual Reproduction
There are 2 types of reproduction, sexual and asexual. Asexual reproduction contains the exact same DNA, while sexual reproduction creates a variation in the physical and mental aspect of the offspring produced. In asexual reproduction only one parent is needed, while in sexual reproduction 2 parents are required. Sexual reproduction needs a sperm and an egg to create an offspring. Asexual reproduction, on the other hand, has different types of ways to produce an offspring. Binary fission being one of them. Binary fission is when the DNA in a cell doubles and is split in two; one example of this is a prokaryotic cell like bacteria. Another type of asexual reproduction is budding, which is when an offspring branches and grows from the parent. Also, fragmentation is another form. This is when and torn or broken piece of an organism forms a new organism of the same species. For example, a worm can recreate itself. Vegetative propagation is similar, this is when a plant grows roots that create its' own individual. An example of this is strawberry plants.
This shows vegetative propagation!
Meiosis and Mitosis
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Meiosis is the type of cell division that results in cells (gametes) with half the chromosomes. Meiosis results in 4 haploid daughter sex cells. The cells produced in mitosis are all identical to one another. The first part of meiosis consists of the steps of mitosis. Mitosis is used to make different cells for the body. For example, skin cells. First, interphase happens for 90% of the time. During interphase the chromatin "hangs out" in the nucleus. Next, the nucleus disappears and the spindle fibers spread out, prophase 1. Then, the chromosomes line up, metaphase 1. Next, anaphase 1 occurs, causing the chromatids to separate. Then the two cells form, caused by telephase 1. All of these first steps occur in mitosis. Meiosis picks up after telephase 1. But, after telephase 1, prophase 2 occurs causing the nucleus of the new 2 cells to disappear. Then, metaphase 2 occurs causing the chromosomes to line up in the middle. Next, anaphase 2 splits up the chromosomes. And at last, telephase 2 causes the 4 haploid daughter cells to form.
Clam Reproduction
<------ This is an image of broadcast spawning of a sponge underwater. Oysters reproduce in the same way. Clams reproductive system and ways are different than humans because clams can go through a cycle of sex change. Also they don't chose who to mate with like some species do. Did you know oysters have 20 chromosomes? Clams mate by releasing their sperm and eggs, after the temperature gets warm (spring and summer), this is called broadcast spawning. The gametes then spread out into the large ocean and combine to produce and develop an offspring. The clams release their gametes in many different eggs in order to spread and out the cells in a variety of places. Some eggs and sperm connect, some get eaten, some just lie around. [1] Female clams can let out millions and millions of eggs into the ocean in their life. The larva clam is born after the sperm and egg connect. The larva moves freely in the ocean looking nothing like their parents. It looks like little saucers covered with cillia, to help them move in the ocean. Also they have 2 valves that will soon turn into the 2 parts of the shell. [2] As the clam develops, it's shell grows and it takes on the lifestyle of an adult clam. The lifestyle of an adult clam is basically living under the sand in the ocean and being immobile. Furthermore, an increase in temperature of their habitat causes them to spawn less eggs and sperm.
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