importance of reproductive success
Reproducing successful is important! Now that's out of the way. Let's get to the why. What do you think would happen if you don't have no siblings and babies to carry on your family genes and names? Your family genes and names would be gone. In the animals, and those things that are not animals , they have cells, and need to reproduce in order for their line, their family to continue. The more you reproduce and have babies, the harder it is to be killed off and your family to be gone. Not all survive these reproduction stages though, because sexual reproduction is more complicated than asexual reproduction, but one thing they both have in common is that most of the time they both end up in another organism.
What cells go through to multiply
All cells go through something that are the same but they are called different things. Mitosis is the splitting of the cells, but only once. The phases are called prophase, metaphase, anaphase, and telophase, in that order exactly. Animals that goes through asexual reproduction cells goes through mitosis. While animals that goes through sexual reproduction and have complicated cells goes through meiosis. Meiosis is also the splitting of cells but twice instead of once. The phases of meiosis are called Prophase 1, Metaphase 1, Anaphase 1, and Telophase 1. That is only the first round of meiosis. In this round you would end up with 2 cells called haploid cells. The second round phases are called Prophase 2, Metaphase 2, Anaphase 2, and Telophase 2. At the end of this round you'll end up with 4 cells, called daughter cells.
Asexual Reproduction
In asexual reproduction there's only one parent. In asexual reproduction mitosis takes place. The reason mitosis takes place instead of mitosis is because when mitosis takes place, the cell is splitting to two, but it has the same amount of chromosomes has it's parent. The places we see asexual reproduction take place is in vegetative reproduction, fission,or budding. In vegetive reproduction, new plants grow without sexual reproductions taking place. This does not go for all plants because most plants reproduce sexually. Let's take strawberry plants for example, they reproduce sexually. Their roots just keeps spreading into the ground and comes back up. Some may think that it's a whole new strawberry, and in some ways they are right, but that strawberry is the daughter of the strawberry plant next to it, it is completely identical to it's mother plant. In binary fission reproduction, a new regeneration takes place because the cells were separated. We could see binary fission take place in star fish, when you cut off an arm, another one grows back and the piece that was cut off would grow into a whole new starfish it's self. In budding reproduction, a whole new organism is growing from it's parent organism. We see this taking place in yeast, where it's daughter is growing from it's parent. On thing to keep in mind is that in all of these asexual reproduction, there's always one parent. The gametes the parent has, the child would have to same amount for sure and would look exactly like the parent.
Sexual reproduction
In sexual reproduction there is two parents that are involved in making a child. Mammals go through sexual reproduction. Because there are two parents doing the reproduction together, meiosis takes place. In meiosis only half the number of chromosomes are needed from each parent to make a whole set. The egg, from the mother, has half of her chromosomes, and the sperm, from the father, has half the number of eggs. When an egg and sperm combines it's called fertilization. Fertilization could be external or internal. In external reproduction, it needs a medium such as water, which the sperm can use to swim towards the egg cell. In internals fertilization, it occurs within the female, that's what humans do. DNA is a huge and important problem in sexual reproduction Because there is more then one parent, mistakes are easier to occur than in asexual reproduction. Mistakes that could take place is mutations may occur. The different types of mutations are subtractions, deletions, and insertions. In insertion, a nitrogen base is inserted or added to the sequence. In deletion a nitrogen base is deleted or removed from the sequence. In Subtractions a single nitrogen base is subtracted for another in a codon. This is the least harmful of the three mutations because there is still the same amount of bases, even though it's completely different.
clams reproduction
Clams reproduce sexually. Hard to get your head around right? I bet your asking how, when they have a shell around them? Or do the to parts in them, male and female like plants do? Let me answer those questions for you. clams have these special tubes, called siphons and what they would do is that they would sprout their eggs out and the male would spurt their semen at they same time. They have this special sense that let them spurt both the egg and the semen at the same time, so that the egg could be come fertile. Clams don't come into contact much with each other so because of this they when they do end up in the presence of each other, female and male, they try to reproduce as much as they can together. Clams's sexual reproduction is external and so the fertilized egg might float away and land somewhere to grow. Some might survive to grow and grow the shell around themselves to protect them. The unlucky one won't survive and some get eaten by fish that are around.