Have you ever wondered why every living thing in the world is different? There are over 6 billion humans in this world and every single one of us is unique. Some of our characteristics are inherited from our parents, but others are affected by external influences like upbringing and environment. Biological variation has played an essential part in the evolution of life on this planet, and ensures the continued existence of healthy populations. This video looks at variation in living things, at the level of whole organisms (plants, animals and humans). It begins with the pioneering observations of Charles Darwin and his theory of the "survival of the fittest." The distinction between genetic variation and environmental variation is clearly explained, as is the difference between continuous and discontinuous variation. Taking a group of school children as an example, we see how variation can be observed and quantified. The practical consequences of natural selection are evident all around us, but the video also discusses artificial selection in plant and animal breeding. The video is careful to point out that, when it comes to breeding, there is no "best" solution, and indeed variation is the key strategy to fighting challenges to the survival of any species. 20 minutes. © 2003.
Part of the Biology Basics Video Series.
