Extinction of Species | Evolution | Biology | FuseSchool

When a plant or animal species that once lived stops existing entirely, we say that that species has become extinct. Why do certain species of plants and animals sometimes become extinct? According to the theory of evolution, individuals of the same species show a range of variations. Some individuals have characteristics that are better suited to their environment, making them more likely to survive and reproduce, whilst others are less well adapted. These less well adapted individuals may eventually fail to reproduce and eventually their genes are removed from the population. If an entire species fails to adapt to changes in its environment, or compete with other organisms for resources, and its birth rate is lower than its death rate, then it will become extinct. Over 99% of all the species that have ever lived are now extinct! Typically, most organisms become extinct within 10 million years of their first appearance, although some species have survived without much change for much longer than this. These long-surviving organisms are sometimes called “living fossils”. The African aardvark and the Himalayan red panda are two examples of such living fossils as both have remained genetically unchanged for millions of years. From time to time, an event takes place on Earth which causes a mass extinction. These mass extinctions are identified by a significant and often devastating change in the number and variety of organisms alive at one time. The most famous mass extinction, called the K-T extinction event, occurred about 65 million years ago and involved the extinction of the dinosaurs. The most devastating extinction event happened 251 million years ago, and completely eradicated 96% of all known species. This was probably due to a comet or asteroid impact. Today, many species are becoming extinct at an alarming rate. This is of great concern to biologists and ecologists. It is currently estimated that 50% of all living species will be extinct by the year 2100. What can we do to slow or halt this spiral of extinction? Stopping habitat destruction is a key starting point, as well as becoming greener, lowering our carbon footprint and using sustainable products we may be able to affect this, and it’s up to all of us to play our part. Our teachers and animators come together to make fun & easy-to-understand videos in Chemistry, Biology, Physics, Maths & ICT. VISIT us at www.fuseschool.org, 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: https://twitter.com/fuseSchool Access a deeper Learning Experience in the FuseSchool platform and app: www.fuseschool.org Friend us: http://www.facebook.com/fuseschool This Open Educational Resource is free of charge, under a Creative Commons License: Attribution-NonCommercial CC BY-NC ( View License Deed: http://creativecommons.org/licenses/by-nc/4.0/ ). You are allowed to download the video for nonprofit, educational use. If you would like to modify the video, please contact us: info@fuseschool.org Click here to see more videos: https://alugha.com/FuseSchool

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