Variation | Genetics | Biology | FuseSchool

Click here to see more videos: CREDITS Animation & Design: Waldi Apollis Narration: Dale Bennett Script: Lucy Billings Look at these baby animals. You will have immediately observed how cute and fluffy they are but you will also have noticed that they are different - they vary. Yes - some are puppies and some are kittens. There is a great deal of variation between species but also there is variation within a species. One puppy is fluffier than the other, they have different colour fur and the kittens have different coloured eyes. Variation is the differences in the characteristics of individuals in a population. It can be due to genetics, the environment or a combination of both. Let’s start with genetics. Different members of a population have different DNA, unless they are identical twins. This means they have different versions of genes, called alleles, and these alleles give rise to different characteristics. For example, on the eye colour gene this kitten has an allele for blue eye colour whereas this kitten has an allele for brown eye colour. If the species reproduces by sexual reproduction, the random mixing of alleles from both parents results in extensive genetic variation within a population of a species. This means that some individuals are better adapted to their environment than others, allowing natural selection to take place. For example, in a population of rats, some will have better eyesight than others. These will be able to avoid being eaten by predators so are more likely to survive to reproduce and pass on this advantage to their offspring. Some examples of variation in humans that are controlled only by genes include eye colour and blood group. If you have blood group A it is because you have the alleles for this characteristic. This is genetic variation, and it is something that you were born with, and nothing can change it. Some variation is due to the environment, or lifestyle of the organisms. Examples in humans are hair length (it depends on how short you decide to cut it), your accent, as this is linked to where you live and if you have any piercings, tattoos or scars. These are characteristics that you acquire throughout your life. Many characteristics are due to a combination of both genetics and the environment. For example, the height a person can grow to is determined by genetics - tall parents tend to produce tall children. However, a person will not grow to their potential height unless they eat a healthy, balanced diet. Also, there is some debate on how much intelligence is due to genetics or the quality of education a person receives - is intelligence more due to nature or nurture? To answer these questions scientists can do experiments using identical twins. If the characteristic in both twins is the same then it is most likely due to genetics. If it is different, then the environment has played an important role. For example, identical twins will have the same eye colour as this is only due to genetics but they will have different personalities, talents, likes and dislikes and this shows that these are also influenced by the environment. So, in this video we learnt about variation, and how it can be controlled by genetics, the environment or sometimes both. Our teachers and animators come together to make fun & easy-to-understand videos in Chemistry, Biology, Physics, Maths & ICT. VISIT us at, where all of our videos are carefully organised into topics and specific orders, and to see what else we have on offer. Comment, like and share with other learners. You can both ask and answer questions, and teachers will get back to you. These videos can be used in a flipped classroom model or as a revision aid. Twitter: This Open Educational Resource is free of charge, under a Creative Commons License: Attribution-NonCommercial CC BY-NC ( View License Deed: ). You are allowed to download the video for nonprofit, educational use. If you would like to modify the video, please contact us:

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