Animation description
In this animation, a large genealogy appears showing the pattern of ancestors and descendants within one family over many generations. An arrow pointing down indicates that time progresses from top to bottom, with "today" at the bottom of the diagram. The topmost lineage of the diagram is labeled "family's common ancestor." Then the genealogy rotates 180 degrees, so that it now looks like a tree, with trunk at the bottom and branches at the top. The bottommost lineage on the tree is labeled "life's common ancestor." An arrow shows that time progresses in the upwards direction on the tree, with the bottom of the tree representing 3.5 billion years ago. The message is that evolutionary trees are much like family genealogies, but over longer periods of time.
Animation text
Panel 1:
This kind of branching diagram, or tree, is drawn the opposite of a genealogy, so that the oldest ancestors are at the bottom.
Panel 2:
Even though all life is related, resemblances fade over time, so those relationships are not always obvious.