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Hi everyone, this week's video is about Charles Darwin and vestigial structures.

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Darwin was the scientist, who you probably already know, who formulated the theory of evolution that we still learn today.

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His famous book, On the Origin of Species, was published in 1859.

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In this book, Darwin had two main ideas.

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First, that all the organisms on Earth are connected and related to one another.

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And second, is the theory of natural selection, what some people call survival of the fittest.

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Darwin's idea was that over time, the organisms that are best suited to their environment survive,

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and pass on their genetic traits to future generations.

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At the same time, organisms that are less adapted die or reproduce at a lower rate

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and might be eliminated from the ecosystem. Of course, this isn't happening in 10 years

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or even 100. Natural selection occurs over thousands or millions of years,

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and usually the changes are very small. So what evidence can we find to support Darwin's theory?

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You can find lots of evidence in vestigial structures.

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These are little leftovers, parts that used to have a purpose but not anymore.

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Here are three examples of vestigial structures in our own bodies.

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First, the appendix.

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The appendix is a small organ between your large intestine and small intestine.

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Darwin thought that this was a leftover caesium, which is an organ in other animals that helps to

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digest plants. One in every 20 people have to get their appendix removed because it can burst

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and cause a lot of pain. Second is the tailbone or coccyx, which is the bone at the end of your spine.

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As you can see in the name, this is a leftover from when humans evolved from primates with tails.

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The third example is wisdom teeth, or third molars.

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These are leftovers from the first humans, who mostly ate plants and needed more teeth

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to chew.

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But when agriculture developed and our diet changed, our mouths and jaws slowly got smaller.

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So now, when wisdom teeth grow in, a lot of people need to have them surgically removed

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to prevent pain.