HeLa Cell during Anaphase. Credit: Matthew Daniels/Wellcome Images
Because #Meiosis.
The following video deals with the question: “Why kids don’t look like their parents”. I assure you, it will be answered. Basically, it is a matter of possible combinations, the nature of meiotic events. Which include what happens in metaphase, a.k.a. ‘independent assortment’, synapse formation, and crossing over.
The Hypertextual Lounge 
Kids don’t look exactly like their parents because when cells undergo Meiosis, the chromosomes recombine and assort traits. Also that there are many possibilities (gametes) made in the process so the possibilities that there will be identical brothers or identical kids amd parents are very little but they will have some traits of the father and the mother mixed. http://en.wikipedia.org/wiki/Mendelian_inheritance
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Could you imagine the biodiversity in the Amazon jungle without sexual reproduction?
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The reason why children do not look exactly like their parents is due to the process of meiosis. Each sperm cell is composed of a random mix of the father’s parents genes and the same thing happens between the egg and the mother’s parents genes; making each and every kid that a couple has a completely different and random combination of genes. http://science.howstuffworks.com/life/genetic/question92.htm
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We can look at this from another perspective. If everyone were to look the same that means everyone has the same phenotypes, which would mean that the amount of different genotypes would be extremely limited. That would mean that evolution wouldn’t even take place or it would be way slower than what it already is.
Not looking the same inherently means different genotypes, which can then mix and create new ones, eventually fueling the process of evolution. That being said, crossing-over is natures way to avoid making every offspring the same, so that more genetic diversity is achieved.
Furthermore, if this randomized selection of genes didn’t occur, then reproduction would only be like making a copy-paste of a file. This applies to all living organisms. If every organism in a specie were the same, then would evolution be relevant? If that were the case, only a mutation could change the species doomed fate to remain the same forever leaving it prone to all of its weaknesses.
That being said, I believe meiosis is just one of many of nature’s failsafe measures to avoid what I just described from happening. Even if meiosis didn’t produce visually different organism, enzymes would surely mess up along the way, creating a mutation that could be relatively significant. Thus, avoiding the offspring to look exactly like its parents, and allowing its offspring to look and be different than him/her.
The point I’m trying to get across is that nature needs ways to fuel evolution, or change over time, and it has plenty of ways to do so. Such ways might include making errors while copying DNA, resulting in mutations, or simply by the crossing-over and genetic recombination that occurs during Meiosis.
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Meiosis—a.k.a. “sex”—is a huge deal in nature. Probably nature’s greatest invention. Great comment, Eduardo. It is pretty evident that you know your stuff.
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In addition to the genes each parent expresses in their looks, they carry within them genetic traits from their respective families that aren’t seen in their physical appearance. This can also account for why their kids don’t look exactly like them.
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I find really impressive how this process undergoes. The fact that genes passed from our parents undergo series of changes and translations in order to form a single trait of ours is simply amazing. Each of the cell processes is very complex but being able to study them was really useful and entertaining.
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Meiosis is a type of cell division that, in humans, occurs only in male testes and female ovary tissue, and, together with fertilization, it is the process that is characteristic of sexual reproduction. Kids dont look like their parents because meiosis serves two important purposes: it keeps the number of chromosomes from doubling each generation, and it provides genetic diversity in offspring. This diversity is caused by the mixing of alleles, therefore a kid will never look identically to its parent. Here’s a video that really helped me understand the process of meiosis.
https://m.youtube.com/watch?v=ijLc52LmFQg
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Meiosis is a specialized type of cell division that reduces the chromosome number by half. Cells normally have two copies of each chromosome, one donated from each parent. This is the diploid condition. Meiosis transforms a diploid cell into four haploid granddaughter cells , each of this cells contain a single copy of each chromosome. This process helps ensure genetic diversity and for this reason kids do not look exactly like their parents.
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As I’ve said in previous comments, Meiosis is a huge deal in the evolution of life on Earth. In other words, a big update. The following link gives us information on how meiosis originated. There are two competing theories: meiosis evolving from mitosis, and meiosis evolving from bacterial transformation: http://en.m.wikipedia.org/wiki/Origin_and_function_of_meiosis
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All humans look different (maybe save for identical twins) due to meiosis and the shuffling genes undergo in this process. It is beneficial for all species that this takes place in order for there to be genetic variation which is advantageous when it comes to the survival of a species. Because of genetic variation, natural selection can run its course and bring forth adaptations that will suit a species and set evolution in motion.
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Even if children can’t look exactly like their parents, theoretically, isn’t it possible that there be siblings, who share the same parents and have the exact same DNA but aren’t identical twins? The chances for it ever happening would be almost 0 (still depends on how similar the parents are genetically) being that the gametes from both the male and female have to be exactly identical after meiosis. As long as their parents are the same, there should be the most minimal chance of it occurring. Maybe it has happened once and went undocumented, maybe it will happen in the next years, maybe it has appeared in a species that isn’t human, or perhaps it’ll never in the future of our earth happen, but I think it’s an interesting possibility.
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Kids don’t look exactly like their parents because they’re carrying both sets of genes and because in sexual reproduction, an offspring only gets 23 pairs of chromosomes from both parents, as in meiosis cell division. Therefore this leads to a difference in the genetic material through which humans were made.
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In meiosis, the selection of gametes in fertilization is random, which contributes to genetic diversity. If the gametes would always be the same, the offspring would look exactly like its parents. This would result in the great majority of organisms to look alike, which would be a disadvantage for evolution by slowing down its process.
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It’s amazing how each offspring is similar to their parents but, at the same time they are different. Each human cell contains two sets of 23 chromosomes, which are responsible for the characteristics of an individual. When a female and a male undergo sexual reproduction, a random choosing of 23 chromosomes, from each parent is made, resulting in the union of two gametes, each of 23 chromosomes. The resulting cell, of 46 chromosomes, is called the zygote. The zygote then undergoes mitotic divisions and differentiation to form an adult. Why don’t kids look like their parents? Because sexual reproduction involves the union of two different gametes, one from each parent, it is impossible to create an organism identical to one of them. By contrast asexual reproduction gives rise to an individual that is identical to the parent.
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By all practical purposes, asexual reproduction is like cloning.
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This video is great! It helps me understand the process of meiosis and the differences it has between mitosis. Also, it answers a question I’ve been asking myself for years (Why children don’t look like their parents or siblings). Although I don’t know if this is directly linked with meiosis, I find it interesting how a child can inherit a trait not seen in the parent, but seen in an earlier generation of the family. It’s interesting how the trait could be manifested in the grandparent and child, skipping a generation.
Along with this video, I’ve been studying from this picture: http://www.ib.bioninja.com.au/_Media/meiosis_med.jpeg
I thought that I should share it just in case someone else would want to study from it. The video explains the process of meiosis more detailed, and the picture only accounts for meiosis I, but both of these sources have helped me a lot.
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Great link, Laura. Thanks for sharing.
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A person has a set of chromosomes. They contain two halves that join in the middle to look like an X. Half of the chromosomes come from the mother and the other half from the father. Each half contains a complete set of genes, so each chromosome has two copies of every gene, the dominant gene is the one mostly shown. I think children look different from their parents because of different combinations of chromosome from their mother and father. Also when those genes and chromosome go through different processes they undergo changes and change the traits and genes.
http://science.howstuffworks.com/life/genetic/question92.htm
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Even where children’s genes look identical to their parents, their bodies and minds could well differ, influenced by many other factors, including the portions of the parents’ DNA that don’t code for genes, their environment, and their behavior. When it comes to repoduction nature is absolutely amazing. In this link it explains to us how kids from same parents look so different. http://science.howstuffworks.com/life/genetic/question92.htm
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The process of meiosis is something so wonderful and fascinating how it explains most of our questions involving genetic traits. This shows exactly how no parent could be exactly like their child neither physically nor their behavior because you din’t get all 46 chromosomes from just one parent. After this I still had some doubts as to why siblings don’t look the same if they have the same chromosomes from the same parents. The link below helped me understand that at then end of the day when genes are passed down the one that gets to you is really is random there is no logical explanation as to why one sibling got that specific trait. This is just an another example of how wonderful it is to know these different processes like meiosis and mitosis and how DNA helps us in understanding how a person is how they are. http://genetics.thetech.org/ask/ask394
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I think it’s very cool how we don’t look exactly like our parents, but we share certain traits with them. But in hindsight, we also share chromosomes from our four grandparents, which makes things even more amazing. We all have different combinations of genes. We have 23 chromosomes from the sperm and 23 chromosomes from the ovule. The greatest thing about this is that you don’t know which of the 46 chromosomes from your parents divided during meiosis so you can never know how the offspring is going to look. Sexual reproduction is nature’s grandest lottery.
http://science.howstuffworks.com/life/genetic/question92.htm
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