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Hello, everyone.
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Today we're going to be talking about how evolution accounts for the similarities between organisms.
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So let's put this into context and talk about how the human body needs 25 elements in order to survive.
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These elements exist in the same relative abundance or percentages.
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So we have 65 % oxygen, 18 .5 % carbon, 9 .5 % hydrogen, 3 .3 % nitrogen, and the other 3 .3 % nitrogen.
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Is made above the other 21 elements that we need to survive.
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And the thing about these elemental compositions that really fuel us is that it's really similar between organisms, even ones that are really different.
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There is variation, so like plants, they only need 17 elements to survive because they're less complex than us.
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And there's also going to be variation in the exact percentages of each of these.
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But all living organisms need these four main elements to survive.
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Survive.
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And evolution can explain these similarities, but first let's talk about what evolution is.
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Evolution is the process of how organisms developed and diversified from other forms of life.
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So i think millions of years ago, this implies that there must have been one form of life.
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And over time, as it reproduced, the life was modified to be better fit for its environment.
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So the reason that our elemental compositions are so similar to other organisms is because we came from the same ancestor a long time ago.
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This ancestor would be like a very simple single -celled organism.
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But since all organisms need these elements, we know that that cell, long ago, needed all these elements to do all of its functions to survive.
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But let's talk about evolution a little bit more fine -grained to understand how we can really do.
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Account for similarities and determine how similar different organisms are.
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So the first thing i want to talk about is an evolutionary process called speciation.
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For this example, we're going to switch to something a little different.
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We have a population of birds here.
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So there's natural variation in this population.
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So they have traits that, you know, make them look a little different or behave a little different.
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In this case, the variation is on their beak size.
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So some of the birds have really large beaks, some of mediums, some of the birds, size beaks and some have really small beaks.
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And let's say that these birds live in an environment where it is super forested and the way that they get their food is by pecking into the tree to get insects...