As the continents broke apart over time, life forms diverged and became different from each other. Fossils found in South America, Africa, Australia, India and Antarctica have similarities because those continents were once joined together as one landmass. Sometimes these populations are isolated by geographic events, such as earthquakes or floods.Ĭontinents move due to plate tectonics, which causes populations of a species to become separated. Populations of living species can become separated because of natural disasters. This is because their gene pools will be separate from each other and evolve over time. When people are separated, they can develop different characteristics. If you go far enough back in time, all the animals will be connected to one another. There are many different species of animals on Earth, and each one is related to every other. The most famous example is how we’ve bred dogs, which are now very different from their original wild wolf ancestors.īig Idea #1: The wide spectrum of life today is the result of populations being separated and hence evolving separately. This can result in a new species with characteristics that differ from those of its ancestors. In this way, each individual is a unique combination of genes that were not present in any previous generation.Īrtificial selection is the process of breeding animals or plants to select for certain characteristics. Genes are passed on from one generation to the next. Genes determine what an organism will look like during its embryonic stage because they provide instructions to the body on how it should grow. The characteristics that are being selected for in evolution aren’t really the traits, but rather the genes that cause those traits.

The same process has been applied to other things as well, like creating tastier cabbages. They breed certain characteristics, like short legs, into the dog by selecting and mating dogs with similar physical features.

They’re all descended from wolves.īreeders have been breeding dogs for thousands of years to create various kinds of dogs. Think about all the different kinds of dogs, from big Great Danes to little Chihuahuas or short-legged Dachshunds. 1-Page Summary of The Greatest Show On Earth Overview

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