Darwin and vestigial structures | Mediateca de EducaMadrid

Hi everyone, this week's video is about Charles Darwin and vestigial structures. 00:00:00

Darwin was the scientist, who you probably already know, who formulated the theory of evolution that we still learn today. 00:00:07

His famous book, On the Origin of Species, was published in 1859. 00:00:16

In this book, Darwin had two main ideas. 00:00:23

First, that all the organisms on Earth are connected and related to one another. 00:00:27

And second, is the theory of natural selection, what some people call survival of the fittest. 00:00:33

Darwin's idea was that over time, the organisms that are best suited to their environment survive, 00:00:42

and pass on their genetic traits to future generations. 00:00:49

At the same time, organisms that are less adapted die or reproduce at a lower rate 00:00:53

and might be eliminated from the ecosystem. Of course, this isn't happening in 10 years 00:01:00

or even 100. Natural selection occurs over thousands or millions of years, 00:01:07

and usually the changes are very small. So what evidence can we find to support Darwin's theory? 00:01:14

You can find lots of evidence in vestigial structures. 00:01:23

These are little leftovers, parts that used to have a purpose but not anymore. 00:01:27

Here are three examples of vestigial structures in our own bodies. 00:01:34

First, the appendix. 00:01:39

The appendix is a small organ between your large intestine and small intestine. 00:01:41

Darwin thought that this was a leftover caesium, which is an organ in other animals that helps to 00:01:47

digest plants. One in every 20 people have to get their appendix removed because it can burst 00:01:53

and cause a lot of pain. Second is the tailbone or coccyx, which is the bone at the end of your spine. 00:02:00

As you can see in the name, this is a leftover from when humans evolved from primates with tails. 00:02:10

The third example is wisdom teeth, or third molars. 00:02:16

These are leftovers from the first humans, who mostly ate plants and needed more teeth 00:02:22

to chew. 00:02:28

But when agriculture developed and our diet changed, our mouths and jaws slowly got smaller. 00:02:30

So now, when wisdom teeth grow in, a lot of people need to have them surgically removed 00:02:37

to prevent pain. 00:02:43

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