A Family Tree is a Diagram that Maps out Relationships

Usually when people talk about human evolution they focus on the part of the story that is about apes, and the stone age. We are going to zoom out and get a bigger picture of the family tree.

Scientists are using genetic information to put together a new vision of how all life is part of one big, extended family.

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DNA and the Tree of Life
DNA and the Tree of Life

Scientists are using genetic information to put together a new vision of how all life is part of one big, extended family.

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Family Tree
family tree

For most of human history only the rich and powerful had family trees.

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Ancestor
Ancestor

A family tree shows relationships between ancestors and descendants. The wolf is the ancestor of all dogs.

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Descendants
descendents

Dogs are the descendents of the wolf.

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Genetic Tests
genetic tests

How do we know that wolves and dogs are related? Through genetic testing. It is only very recently that we’ve developed methods of reading the DNA. It’s often called decoding. For example, you might have heard the phrase “Decoding the Genome.”

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Double Helix of the DNA
DNA.

Since DNA plays a big part in this story, let’s take a minute to learn some basics about DNA. 

DNA is a molecule. 
DNA is found inside living cells.
All living creatures have DNA. 
DNA is shaped like a double helix. 

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The Slinky is a single helix
The Slinky is a single helix

The helix is a spiral shape. The slinky toy is made from a single helix of metal or plastic. 

All DNA, whether it is from a dog, a human or a single-cell bacteria, shares this distinctive spiral structure. This unique pattern of the DNA is one of the many clues that all living creatures are related to each other. 

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Decoding the Genome
Decoding the Genome

Over the past decade scientists have decoded the genomes of thousands of different species. From comparing the DNA of animals, plants, bacteria and fungi they’ve discovered that ALL living creatures have some overlap in their genetic code. This is the genetic evidence that leads scientists to believe all life-forms are part of one, big, extended family.

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Tree of Life
tree of life

The branches on this chart, from Scientific American Magazine, represent all of the named species of plants, animals, fungi, and microbes on Earth. Humans are part of the circle of life. We are one species among many.

Read more at Scientific American:
https://www.scientificamerican.com/article/all-2-3-million-species-are-mapped-into-a-single-circle-of-life/

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All Roads Lead to LUCA
All Roads Lead to LUCA

Every single living creature has a genetic lineage that leads back to LUCA. The black line traces the Human line of descent that connects us to LUCA.

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All Living Creatures are Genetically Related
All Living Creatures are Genetically Related

In the human family tree we are looking at the human line of descent - this represents all the ancestors between LUCA and you. 

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Human Line of Descent
Human Line of Descent

A branch from a family tree and a timeline are two different ways of looking at the same sequence of events.

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DNA, LUCA & You
Human Line of Descent

DNA is the link that connects You to LUCA.

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One Big Crazy Family
DNA and the Tree of Life

Evolution is the story of how you are related to a very big, very vibrant family of life.